Saturday, 2 January 2016

7b. MacLean, E.L et al (2011) How does cognition evolve?

7b. MacLean, E.L., Matthews, L.J., Hare, B.A., Nunn, C.L., Anderson, R.C., Aureli, F., Brannon, E.M., Call, J., Drea, C.M., Emery, N.J. and Haun, D.B. (2012) How does cognition evolve?Phylogenetic comparative psychology. Animal Cognition, 15(2): 223-238.

Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.


  1. Pt. 1:
    “Increases in social complexity drove the evolution of cognitive flexibility in primates. This hypothesis leads to the prediction that changes in social complexity on different evolutionary lineages should be coupled with changes in the cognitive abilities required to live in increasingly complex social groups.”
    - I think this is quite true, considering cognitive capacity probably has evolved over time, but this suggests that cognitive capacity only grows as a result of adaptation to the social environment. I doubt that social complexity is the only causal mechanism behind cognitive growth, but I see it more like cognitive capacity is shaped by our social environment but the social environment that we’re in comes from our cognitive capacities. Also, predictions only tells us the “how”, not the “why”.

    “A third question that comparative psychologists address concerns the ancestral state for cognitive abilities.”
    “New phylogenetic methods allow researchers to reconstruct values at the ancestral nodes in a phylogeny and to place statistical measures of confidence on these reconstructions… the ancestral state gives us a baseline by which to judge how divergent any extant species is from an ancestral state when further testing evolutionary hypotheses.”
    - How does considering ancestral state for cognitive abilities explain why cognitive abilities have to be evolved? Comparing the extant species with the baseline, the ancestral state, only gives us an idea of how cognitive capacity has evolved, meaning how learning has occurred throughout generations, but not why.
    - Also, as a reductionist cruncher argument, our ancestors may have different cognitive abilities that were far more developed than ours, and as that knowledge gets passed on over time, it becomes less important and less needed to adapt to the environment and thus, degrades or becomes lost. This shows that we need to focus on the present rather than just the past.

    “Anatomical traits (e.g., body mass) tended to exhibit more phylogenetic signal than behavioral traits (e.g., daily path length), corroborating the long-held notion that behavior is more evolutionarily labile than morphology.”
    - What does behavioral traits imply? That individuals born are predisposed to different behavioral traits among their species that is in turn, shaped by the environment differently among individuals? Does this mean learned behavioral traits get passed on as innate traits in upcoming generations?

    1. Pt. 2:
      “Because closely related species share much of their evolutionary history, we typically expect that they resemble one another morphologically more so than distantly related species. This resemblance due to shared evolutionary history is termed phylogenetic signal. Many behavioral phenotypes also exhibit phylogenetic signal, and the same principle is likely true for cognition.”
      - In the case that cognition between similar species will likely resemble each other, would it be due to a social factor or a purely genetic factor?

      “Many phylogenetic comparative methods address patterns of trait evolution, or the relationship between a set of traits. Thus, one major challenge is for comparative psychologists to develop dependent measures that can meaningfully be interpreted as traits... in many cases, it is domains of cognition rather than performance on single tasks that is most interesting for comparative analysis. One potential solution to this challenge is the use of composite measures, derived from multiple tasks designed to measure cognitive abilities in a given domain.”
      “One major advantage of these collaborative papers is that the raw data for many species can be presented, analyzed, and discussed comparatively and comprehensively in a single article. This process helps us escape the disadvantages of only publishing (or not publishing!) data from species separately, in different journals, where the comparative significance of such work is often lost. For example, convincing null results (i.e., a species fails to solve a problem that is related to problems it is successful with and is motivated to solve) frequently remain unpublished and are often considered uninteresting or difficult to interpret when considered in isolation. However, the same results provide valuable information about inter-specific cognitive variation when considered in parallel with data from other species that performed better on the same task.”
      - I think the idea of collaborative papers is great but very unlikely… but I love the idea they point out about publishing null results because failures also provide really important information such as why it failed, which can be used for reference by other papers in the future. The idea of having standardized testing methods is also a great idea, but seems slightly limiting because it focuses on domain specific cognitive capacities rather than viewing cognitive capacity as domain general.

      “Because time and access to animals are limiting resources in comparative psychology, these collaborative endeavors should not impose undue burdens on participating research groups. For this reason, we suspect that the first generation of broad comparative studies will be most successful if they employ testing procedures that (1) minimize or eliminate the need for training, (2) require few trials/sessions per subject, and (3) are easily implemented with few methodological modifications across species.”
      - This seems to impose a lot of limits in areas of research, especially minimizing the need for training, considering evolution never ends, thus a lot of capacities are growing due to learning. However, I really do think they make an important point that access to animals are limiting resources and they’re probably trying to use easier ways and faster ways to test the animals so it’s not an ongoing thing for the animals’ lives.

    2. Some kinds of evolutionary data and analyses (but not this kind) can tell you both how and why behavioral capacities evolved -- but not how they work: not their causal mechanisms; that requires cognitive science (T3) and perhaps also neuroscience (T4).

      The fact that a trait has a social function, or even that it evolved "for" a social function does not mean that it is just passed on by social learning. The capacity itself could be genetic. And that's what "evolved" usually mean. Ditto for (evolved) cognitive capacities.

      Behavioral traits can be inborn (genetic) or learned (or part of each). If learned, the capacity to learn them must be inborn,

      (Oliver, you're quoting too much. Just quote the gist of what you are responding to, not long passages. Or re-tell in your own words what they said that you are asking about or commenting on.)

    3. Hey Oliver,

      Regarding your first point, I have some doubts about the social intelligence hypothesis. While I do think it’s clear that social complexity and cognitive flexibility in primates are correlated, I’m not convinced that the former caused/causes the evolution of the latter. The whole idea immediately prompts a bit of a chicken-or-the-egg question in my mind. It could very well be that this is the case, but I take it with a grain of salt because who’s to say that other factors (e.g. something like food gathering vs spatial awareness) didn’t cause the inverse to be true, namely that increased cognitive ability increased social complexity? I didn’t see enough evidence in either direction to be sure either way.

  2. “New phylogenetic methods allow researchers to reconstruct values at the ancestral nodes in a phylogeny and to place statistical measures of confidence on these reconstructions… the ancestral state gives us a baseline by which to judge how divergent any extant species is from an ancestral state when further testing evolutionary hypotheses.”

    I agree with Oliver H. above, in that I agree that these studies merely show how cognitive capacities have evolved and not WHY they have evolved. That being said, while learning the "why" is important, I think that, in this case, learning the "why" will only get us so far as the present. Learning the "why" is interesting, and I am sure that there are definite trends in the reasons for the evolution of our cognitive capacities, but a large part of the evolution of our cognitive capacities is the current state in which we live and the dynamic social systems and perpetually changing surroundings which help shape our adaptation to environment. Therefore, as we are unable to predict the future state of our environment as well as future states of our "complex social systems", learning the "why", while interesting, may not be as important as learning the "how", which is exactly what this article aims to do and, in my opinion, does quite effectively. Learning the answer to the "how" our cognitive capacities evolve and have evolved can be mapped - because it is more concrete and measurable, even if merely by brain-imaging while performing certain tasks, we can harness that concreteness and perhaps predict how our cognitive capacities will keep changing... And that may inadvertently answer SOME (obviously not all) of the "why" question as to why our cognitive capacities have changed over time. It would, at the very least, provide insight. However, if we were to delve into and expend more effort into answering the "why" question, we would most likely be greeted by abstraction. Interesting abstraction, yes, but abstraction that would be very difficult to predict, and I think it would tell us far less about ourselves than if we were to continue with the "how" question.

    1. An important distinction in evolutionary biology is the one between the "EEA" (the "environment of evolutionary adaptedness" or the original/ancestral environment) and the present environment. This is especially important for human evolution, because today's environment is often radically different from the EEA in which (and for which) some of our behavioral (i.e., cognitive) capacities and tendencies have evolved.

      Another important distinction is the one between the proximal and the distal function of a behavioral trait. The distal cause is not the same as the proximal cause. Organisms eat food because of the taste (proximal) not in order to raise their blood sugar (distal). And they mate because of sexual attraction, not in order to reproduce (distal).

  3. I have to admit that the phylogenetic comparative methods lost me. Even if it is the core of this article, I preferred to focus my attention on another matter, barely mentioned, but which is at least of interest to me.
    “Despite their broad taxonomic focus, many of these early efforts focused on universal laws of learning and often interpreted species differences within the framework of scala naturae”.
    Scala naturae, also named great chain of being, is a ‘religious’ hierarchal way to divide species. The top of the chain is occupied by God, and as you go down (it is hierarchal in nature) you meet lower divinities, ‘kings’ or high graded men, men, animals, vegetation and finally rock and dust. So talking in term of evolution and adaption, tree would be lower in the hierarchal structure because they didn’t evolve the capacity to freely move. Also, human being would be placed on a higher ground because of our superior cognitive abilities (even if those imply destroying nature and exploiting the vulnerable). The question that I want to raise is whether or not, a specific way to categorize living being (and sometimes non-living being) has an influence on our perception of the human species per se. From my experience, most people tend to assume human beings are more complex, more valuable, and more vibrant than other species. I feel I attained a moment in my reflections where overestimating human being is just improper. I’m not arguing that a rock has a soul but that without rocks (so without earth) human species’ potential would be null. Also, you don’t know what it feels like to be a cat. Maybe cats experienced the world in a much deeper, much richer sensorial way. But let’s just assume they don’t, right? In the MacLean article, monkeys and their relatives were tested on inhibitory control task. Human are the best at those kinds of task, and we like to test our far relative primate friends to see if they can match a 2 years old human. What does that truly tells you? It tells you something which is inherent to human perspective. I do not believe this is the only reality there is. There are many others, and we tend to ignore this. We apply our power and ‘superiority’ on nature and on animals in a disrespectful and abusive way. By doing so, I think we have lost the thing that makes us a glorious species.
    Lets come back to the question I asked, as to whether or not our method of categorization has an influence on our own perception as a species. I think it doesn’t. It is inherent to human nature to overdo its aptitudes. Human are clearly more advanced on cognitive abilities, I’m not arguing against that. But, it apparently didn’t provide us with nature’s common sense. The moment we left nature, we decided it didn’t bother us to destroy it anymore. Scala naturae and phylogenetic methods of categorization have distinct properties, but both are intrinsic to human.

    1. Yup! I definitely didn't manage to fully internalize the phylogenetic mechanisms either.. though i think the details are pretty irrelevant to what we need to extrapolate from the article, which i think is the necessity to de-anthropocentralize (move the focus towards non-human animals) our questions on why 'we' do what 'we' do (so as to subsequently better understand both how and why we do it by widening our scope), which is nicely summarized in the following excerpt: "Without recourse to questions of phylogenetic history and function, we cannot understand how or when species evolved to differ cognitively. Moreover, we cannot test 'why' certain lineages-- including humans -- have evolved the cognitive availabilities they possess."

    2. understanding how diversely and widely certain cognitive features we (humans) possess may be expressed in the non human world will certainly help us understand why these features will have been selected for in our own species.

    3. RPB: The "scala naturae" was a precursor of modern biological taxonomy and cladistic. It was a linear classification based on superficial observations plus lots of human-centered assumptions (including their extensions into fictional entities like gods.

      Yes, how you categorize things influences how you perceive them and what you do with them (Week 6).

      Modern taxonomy is based on structure and function, including behavioral (cognitive) function -- not on how richly the species may feel, but what it can or cannot do. That said -- V alert! -- what's most important about organisms' feelings is the fact that they can suffer. And part of the superficiality in which most humans have treated other feeling species is that -- since because of the other-minds problem we cannot feel the feelings of other species (and they can't speak, like us, to tell us) -- treat them in indescribably cruel way, assuming it's our right, and besides, we can't even be sure they feel...

      We can map out distances and directions among species comparing their cognitive capacities but, as Jeremy Bentham pointed out: “The question is not, "Can they reason?" nor, "Can they talk?" but "Can they suffer?” ― Jeremy Bentham, The Principles of Morals and Legislation

      (We never "left nature.")

    4. Naima : I think you’re right and that you managed to rephrase my point in a more neutral and holistic way. Obviously, we cannot fully dissociate our perspective, but we can certainly manage to widen our scope when it comes to evolutionary psychology. For example, we could compare a variety of cognitive abilities between species instead of only testing them on what ‘we’ can do.

    5. Professor Harnad: I believe I was wrong on the hierarchal nature of the “scala naturae” and on its actual linearity. Maybe because these days I tend to perceived human nature as degrading, and that I myself became bias toward it!
      Suffering is indeed a crucial aspect when it comes to animals’ rights and treatment. And Jeremy Bentham certainly pointed this out elegantly (and in an innovating way for its time I guess). Maybe what is different about the people who cares compared to the one that doesn’t, it’s that to see animal suffer, makes them feel suffer in return? And what makes me sad now is Bentham statement: “The time will come when humanity will extend its mantle over everything which breathes... ". But it is not today... Why is humanity so selfish in this regard?
      (Now I really went off the topic!!)

    6. Roxanne, I definitely agree that widening the scope of what animals are being theorized about in terms of evolutionary psychology would provide more 'bite' to their theories, otherwise the line between 'evolutionary adaptation' and 'socialization' seems too fine to properly delineate!

      In terms of sexual jealousy for example, does anyone know of studies done on other animals? If it were indeed the case that male sexual jealousy would come out of a need to 'be sure' of his lineage than similar traits would be found in more than just humans (though perhaps in different forms than we would envision in our western monogamous society)

    7. Hey Roxanne,

      This is equally off-topic, of course, but as far as the way humans perceive non-human animals, there is a huge disconnect between what is true about other animals and what we believe is true about other animals. Indeed it would seem that our strict categorizations for that which is human behaviour and that which is not, lends itself to some strong categorical perception which leads to wide gaps between humans and everything else.

      I don't know if you attended the Frans de Waal lecture about primate cognition but I think it fits nicely with your question (even if its a little superfluous to bring up now). Frans de Waal discussed how species-appropriate testing (testing calibrated to the specific needs of a given species) has consistently shown that many aspects of what we would consider 'human cognition' are actually shared by many other species as homologous features (similar features with a shared evolutionary ancestry), and are more widespread than previously thought.

      It would appear that our deep prejudices about animals have until recently, resulted in biased tests which served only to confirm our beliefs about our superiority. But now it's clear that non-human primates can demonstrate problem solving without trial and error learning, empathic motor mimicry, and inequity aversion (a sense of fairness) -- traits which were stereotypically reserved for humans.

      Luckily it seems that our renewed interest in species-appropriate testing will provide a clearer picture of the damage we're doing (by showing us our similarities to other animals), and help us mitigate it.

  4. My understanding of this paper is that its purpose is to outline a trajectory for how we can create an evolutionary tree for cognition. The authors introduce the concept of phylogenetic targeting as an interesting mechanism to show researchers which nearby related species would be best to compare a test subject to. This is done by finding important contrastive differences between similar species to maintain as few variables as possible when testing both species on certain cognitive (or other) tasks. This is part of their specific approach to help fine tune the testing process for biologists and psychologists so that their test results can be more compatible with other researchers and be used more effectively in comparative studies. This follows into their overarching goal of coordinating large groups of researchers to share their data and research to allow for a more cohesive field of study. In order for steps to be made in determining an evolutionary tree for cognition, and possibly finding mechanism for it, there must be a large degree of coordination between research groups in order to compare large amounts of species and to unite for a common goal.

    A question I have is why are we always looking the comparisons between humans and chimpanzees or monkeys? Clearly whatever research we have will be biased since we shall always know far more about ourselves than other species. Furthermore I would think most comparisons have already been discovered between humans and apes, so at this point what does it matter? We are looking to find the breaking point between having a certain cognitive capacity and not having it. At this point it seems that there is simply too large an evolutionary step between humans and other species today, so why aren’t we looking to find relationships between species that have smaller evolutionary steps. My ignorance in this field leads me to believe we likely have done such a thing, but my question then becomes why are we not exploring these smaller differences until we can understand them. Surely we should have a good understanding of how smaller cognitive evolutionary steps work before we tackle the big jump between apes using tools and full blown language. Lets study why some apes use tools and others don’t, or why some have object permanence and others lack it. Understanding these smaller gaps in cognitive evolution would hopefully shed light on our bigger gap’s problem that the field is trying to solve

    1. Hey Jordan!

      ... why aren’t we looking to find relationships between species that have smaller evolutionary steps… Lets study why some apes use tools and others don’t, or why some have object permanence and others lack it. Understanding these smaller gaps in cognitive evolution would hopefully shed light on our bigger gap’s problem that the field is trying to solve

      While I completely agree with the above, I don’t think the article is arguing against studying the smaller differences in cognition (i.e. monkeys who use tools vs. those who don’t) - I think what they’re proposing is simply a more effective way to do just that via phylogenetic targeting. The targeting process involves a variety of means, as you’ve described, to reduce confounds and increase statistical power, all of which would in fact give us a significantly greater ability to detect those more minor differences in cognitive abilities.

      A question I have is why are we always looking the comparisons between humans and chimpanzees or monkeys? Clearly whatever research we have will be biased since we shall always know far more about ourselves than other species. Furthermore I would think most comparisons have already been discovered between humans and apes, so at this point what does it matter? We are looking to find the breaking point between having a certain cognitive capacity and not having it

      I might be misunderstanding you, but I'm a bit unsure how this part fits together. You state (and I agree) that the ultimate goal of this research is to learn where in evolutionary history a cognitive capacity evolved, in addition to the function it serves and what exactly differentiates those species that do or do not have it (‘it’ being something like language capacity).

      That being said, I don’t see why you reject studying comparisons between humans and apes, since this is clearly the gap wherein the boundary for such a skill lies. I feel like the only possible way to answer the primary question above is through comparisons of humans and apes. Where else would we acquire the information concerning where on our phylogenetic tree a certain capacity evolved, without studying the differences between members of that phylogeny? In short, how else would we identify that proverbial “breaking point”?

    2. Jordan, you're surprised that people are most interested in the differences between themselves and their nearest relatives?

    3. Along with Stevan's comment, that's what I would have said. The theory of evolution believes that humans came from animals, so it would make most sense to study our nearest relative, rather than let's say a dog or a cat.
      Yes we have progressed and are more capable in many ways than an ape/monkey is, but there is a lot to be said from their cognition and sometimes you cannot always have humans as the subjects in the experiments, so we turn to our nearest relatives. So many questions can be answered from them about EVOLUTION since we supposedly EVOLVED from them

    4. Hi Jordana,
      I agree with what you said, but when you said 'since we supposedly EVOLVED from them' I just want to clarify that we (humans) did not evolve from 'them' (apes). Both apes and humans have their own evolutionary path, and we share a common ancestor.

  5. This paper was an interesting read as it focuses on a more multidisciplinary approach to study cognition (using phylogenetic methods) than the evolutionary psychology approach does. If I am to summarize the evolutionary psychology way of thinking correctly, it is to say that the human brain has many distinct modules that have been specialized by means of natural selection and evolutionary processes (ie. fearing dangerous animals, being protective of kin, mate selection, etc). I found it very informative to read about the statistical modelling techniques used for comparative analysis – how we are able to study the linkage of different traits and across species. The fact that cognition is so multi-faceted was accounted for in acknowledging the difficulty in trying to assess it as a trait in particular species. How can we design a task that is a direct measure of cognition? Well, surely there is not one single task that can show us this but rather different tasks and measures that can account for different “domains of cognition” as is stated in the paper.

    Going off topic.. I cannot help but wonder which aspects of human cognition are uniquely human? Since it has been proven that certain species of animals have human-like intelligence (problem-solving, forming attachment/bonds, using tools, different modes of communication, emotions, self-recognition, etc), what is it that makes our intelligence superior? Is it our collective intentionality and our language abilities? Intelligence seems like such an intangible thing to measure.

    1. Hi Linda,
      I agree, the concept of intelligence is so vague… But there are a few factors that seem to have be set in terms of what makes our intelligence “superior” (or at least, different than other animals). One of them is, as you say, or language ability. We are the only species thus far able to communicate to the extent we do and in such an accurate way. The system of communication we use is much more complex than anything else discovered to this day. Another one is our self awareness (I know that some animal species are self-aware, but I’ll get back to that). And another factor is our use of tools, not only using them as they are but also using them to make other tools, which themselves help make other tools… We’ve gone past the primary use of a tool, which is using it as it is for its intended purpose, and use tools as an intermediary to create other tools in order to achieve an end result. With regard to the self awareness, or even the language (and this is just my speculation/ opinion/ intuition), it’s not so much that those things individually make us superior, but rather their combination and co-occurrence that does. That is, we might discover a species with developed language skills. There are a few species that are self aware. But we are the only species that are able to combine those two things (and more) successfully, while still being able to function. There are many different types of (human) intelligence, but (unless there is some sort of impairment), these factors are common to every single human there is.

    2. Aren't the interesting questions about the differences, and when and how they got there, rather then the "superiority"? Some people are better at some things than others. So are some species. But it's not all a 1-D up/down scale.

      Yes, language is unique to our species. And it's made us able to do lots of things other species can't -- both good and bad things. It may eventually lead to our destroying the planet (we've already destroyed more species than any other species has ever done. And we certainly cause more suffering to more feeling beings than any other species has done. (Does that make us "superior"?)

      What do you mean by "self-aware" and what is it so important for?

      (My guess is that the "self" is just one of the infinite number of things you can be aware of if you are aware at all. And to be aware means nothing more nor less than to be able to feel -- irrespective of what you can or can't feel. -- Bats can feel sonar and we can't. So?)

      Don't confuse self-awareness with mirror self-recognition. And why is my being aware of my self special compared to (1) my being aware of being aware of my self, or (2) being aware of being aware of being aware of my self, or (3) my being aware of your self, or (4) being aware of my nose, or (5) being aware that it's dark outside, or (6) being aware of the meaning of "sentience"? Isn't the remarkable (and difficult to explain) thing the fact that we are aware of (i.e., feel) anything at all? But that capacity we share at least all the way "down" to the simplest invertebrates...

    3. I agree with you Professor Harnad, that it's more interesting to study the differences between animal and human-level intelligence. It's interesting to think of how we view our intelligence – in terms of our ability to use tools to make new tools to make new things (as Leah puts it) or our high-level language abilities. But the question is, why would another animal species need to master this/acquire this domain-specific intelligence? As you say Professor Harnad, bats can feel sonar and that is a trait beneficial to their particular species but one that is not for ours. So how are we to decide which traits signify the “highest intelligence”? Is it not all in relation to the respective species? A quote from the Hitchhiker’s Guide to the Galaxy comes to mind here…

      “For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much—the wheel, New York, wars and so on—whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man—for precisely the same reasons.” (Douglas Adams 1979)

      In a much more drastic sense, are we not allowing other species to reach their full intelligence potential in present day? What I mean is that in the past, us Homo sapiens killed off or “out-competed” the Neanderthals. We drove them to extinction just as we are driving many other species to extinction. Of course no other species has the same cognition as we do but if one ever did hundreds of thousands of years from now... well history would probably repeat itself and we would kill it off.

      Anyways, the question for now is,
      1) why is it that OUR brains have these intricate cognitive capacities that allow us to create all of these technologies and live in such a civilized society
      2) how did these capacities evolve the way they did?

      In answering these questions, I now see how phylogenetic comparative methods can help us to see the differences between and among species as well as to tackle to problem of how these things evolved in the first place. It is important to acknowledge that other species’ brains evolved in parallel, we just had different challenges to face in our respective environments that contributed to making us the way we are.

  6. Using phylogenetic methods to test hypotheses about the evolution of cognition across species seems like an interesting idea, yet I remain sceptical whether these animal studies can really give us an insight into the evolutionary processes or even the animals' cognitive ability.

    It is well-established proposal in psychology and biology that although genes and other 'innate' cognitive architectures are important, the individual's interaction with the environment is also key to their development and can influence how genes in an organism are 'expressed'. However, the animals used in studies like the ones described in the paper have often been brought up in labs or zoos in environments very different to the ones they were 'evolved' to live in. They are in confined spaces, they are provided with regular meals so they do not need to go hunt for food, they only interact with the other animals in their enclosure and rarely come across other species. Therefore, are animal studies not very limited in what they can tell us about their 'natural', evolved cognitive abilities? Merely comparing 'the magnitude of intra-specific-population differences with interspecific differences' does not solve the problem of how the environment affects an animal's cognitive development.

    Additionally, studies are often carried out in very artificial conditions on very artificial tasks. Even within the realm of human psychology it has been shown that people can act very differently in experimental conditions when compared with everyday life. Also, the problem of 'standardizing the essential components of each task while allowing for variation in other parameters required for a valid comparison between species', in my opinion, is extremely difficult to solve and it may be impossible to confirm whether the standardization has been successful. But without confirming this standardization, can any of the data collected by these studies be a useful indicator of evolved cognition across species? I don't think it can.

  7. "These reconstructions can then be considered in relation to fossilized proxies for cognition (e.g., endocast features, artifacts, or ancient DNA). As an example of character reconstruction with confidence intervals, we used maximum likelihood techniques to estimate how an extinct species at the root node of our phylogeny (Fig. 2) would have performed on the example inhibitory control task” (Maclean et al. 2014).

    I am not convinced that this is the correct way to measure divergence from the ancestral baseline. The researchers are assuming that these are indeed markers of cognition and that they can be correlated in 1 to 1 fashion with a cognitive task like inhibitor control task. However, the researcher does try to address this concern by discussing narrow confidence intervals for ancestors of different species and showing that the ancestors probably did have different cognitive capabilities. The use of this is that we could try to pinpoint new differences that allow some species to do better on a cognitive task than others. However, this would again look to brain localization. While I am emphatically for the study of brain localization, I understand in the context of this class it is hard to draw conclusions of brain functions from brain localization. Therefore, I’m not sure what this research yields in terms of the evolution of Cognition other than saying that the appearance of area X is correlated with increased accuracy on ability Y. I still think the narrow confidence intervals don’t tell me much as to the validity of using proxies of Cognitions because I have little understanding of how this statistical analysis is reliable or fruitful. Overall, this method seems to parallel brain localization studies in its lack of usefulness for understanding the “how we do what we do.” Interestingly, using phylogenetic evolution did point to one example of this: by showing that apes could do mirrored self recognition vs monkeys who could not, it can be reasonably inferred that this could be an important artifact for Cognition.

  8. An issue I struggled with throughout this article is the concept of quantifying cognition. At the start of the article, the authors point out the problems with the current methods of comparing general cognitive ability across different species:

    Although analyses of anatomical proxies for cognition (e.g., brain size) allow researchers to analyze large comparative datasets, they rely on the assumption that cognition is a onedimensional, general-purpose mechanism that varies only quantitatively (Healy and Rowe 2007). Empirical evidence suggests that there is no one-to-one relationship between cognitive flexibility and brain size (page 225)

    Here, they make sure to dismiss the idea that we can simply measure cognition by directly correlating it to brain size. Their suggested method attempts to quantify the cognitive ability of different species by evaluating their performance on a particular behavioral task. While this method is certainly more informative than the one involving anatomical correlation, it seems to have its own problems as well. For example, they describe a behavioral test of “inhibitory control,” which requires subjects to reach around a transparent barrier (instead of through it) to obtain their food (page 227). Their cognitive ability is quantified based on their percentage of correct choices. But again, this is assuming that cognitive ability can simply be quantified in this first place. Furthermore, it neglects to include all the other factors that could contribute to a particular animal's behavioral decision at a particular point in time, such as hunger, mood, and familiarity with the experimental environment.

    The authors even acknowledge how uncertain the data becomes when you use the cognitive values assigned to certain species to make inferences about the cognitive values of other species. For example, they use their inhibitory control example to demonstrate how widely “reconstruction scores” can vary based on their input:

    The reconstructed score at the root node of the phylogeny is 57% correct on the cognitive task with a 95% confidence interval from 28 to 86% correct. (page 230)

    The immense degree of uncertainty associated with this inferred cognitive value proves just how difficult it can be to quantify something like cognition, and how this difficulty creates a remarkable degree of potential error when using these quantities in logical deductions. Additionally, where does the other minds problem fit into all of this? Even if we developed a new method for quantifying cognitive ability that removes some of these experimental flaws, how can we ever be sure that our empirical data accurately reflects the animal's cognitive functionality? If we cannot know what the animal is thinking/feeling, or if it is even thinking/feeling to begin with, how can we know that the cognitive trait being examined is actually the trait implemented to complete the task? And how can we know that other cognitive traits and functions are not contributing to the overall behavioral output as well? For example, what if the monkey who was correct only 4% of the time actually does display inhibitory control in other contexts, it just cannot perceive transparent objects like the barrier, which is why it performs so poorly at this task? It seems quantifying something like cognition is going to be much more involved than simple behavioral assays across species like the one described above. Thoughts?

  9. Another (kind of unrelated) thought I had on the issue of experimental design involves the method of phylogenetic targeting. Towards the end of their article, the authors discuss how such an approach can increase statistical significance and take into account limitations caused by real-world constraints:

    By expanding or narrowing the focus of the targeting process in this manner, pairs of species were identified that provide the strongest statistical comparisons and incorporate real-world limitations, such as species availability, whether two species can validly be compared on the same task, and the testing time needed for each comparison (see Table 2). (page 231)

    While I agree that restricting species choices and improving the relevance of the obtained data are important considerations when designing an experiment, I think the authors neglect to address a significant counterpoint: how such an approach can potentially skew that obtained data. They discuss how there are many factors scientists may wish to incorporate into their phylogenetic targeting algorithm, and as such, it is possible that scientists could accidentally include factors that exclude comparisons invalidating their hypotheses. If you start your experiment expecting to get a particular result, your chosen species can potentially skew this result and provide a false confirmation because of the biased you introduced when designing the experiment. Meanwhile, species that would provide more accurate evidence are excluded from the experiment because of constraints in the phylogenetic targeting algorithm.

    Ultimately, I'm not arguing against the use of techniques like phylogentic targeting. In fact, they provide powerful methods for narrowing experimental possibilities while also increasing the relevance of the collected data on both an intra- and inter-experiment level. However, these techniques are not simply the golden bullet comparative psychologists have been waiting for. They come with their own restrictions and complications, which must be accounted for to ensure the validity of the obtained data and all the conclusions that are drawn from it.

  10. “Although analyses of anatomical proxies for cognition (e.g., brain size) allow researchers to analyze large comparative datasets, they rely on the assumption that cognition is a one-dimensional, general-purpose mechanism that varies only quantitatively (Healy and Rowe 2007). Empirical evidence suggests that there is no one-to-one relationship between cognitive flexibility and brain size, while cognitive skills across different domains are not necessarily highly correlated with each other either within or across species.”

    I had a bit of a hard time with this assumption. Not to fully resign myself to strict modularity, but I think we can all agree that different species have behavioural and cognitive capacities that are specialized for what they need to do. To understand cognition meaningfully would be to understand that all different species have different things going on inside their heads so that they can do different things in order to survive. So the assumption that cognition is one-dimensional and varies only quantitatively is quite problematic for me. There’s a tremendous amount of qualitative variation between species (though how we can access this is another question). A bat doesn’t just have less cognition than a human does. The cognitive abilities of a bat are qualitatively different than ours.

  11. Pinpointing exactly when in a species’ ancestral history they gained a cognitive ability (I’m looking at the mirror test for great apes) would be exceptionally hard. I know nothing (apart from this paper) on phylogeny but could we know for sure whether the apes gained the trait after diverging from monkeys, or if monkeys too had that trait and lost it through later evolution if it wasn’t of use to them anymore? Cognitive flexibility doesn’t leave a fossil per se, (although the behaviour it facilitates might), and brain correlations in two species don’t necessarily equal similar cognitive flexibility.

    “A majority of cognitive traits likely evolve along more subtle dimensions and will not clearly map onto the main lineages of a phylogeny”

    Looking at the evolution of behaviour (which as the article points out, is way more malleable compared to physical evolution), mapping it is challenging but mapping the evolution of cognitive capacities is a separate and more formidable feat. When we say that we are studying the evolution of cognitive skills by observing our close relatives, are we really just studying the evolution of behaviour? If I can do Task X, and my closest phylogenetic relative can do Task X too, there’s still no way of seeing how similar our patterns of cognition are. Moreover, if our capacity for categorization is hardwired into our brain but what we categorize isn’t, and is instead shaped by learning, doesn’t that make behaviour an unreliable measure to a certain extent? The paper focuses mostly on problem solving skills that have a tangible output (Gorilla detours around glass to get a sandwich etc.) but we are still missing quite a few cognitive phenomena.

    However, the above grumbling is not to say that I’m throwing out phylogenetic measures to study cognitive evolution. Most of the paper I agreed with: I was impressed by their methodology, the fact that they recognized that a single task is not enough to measure a cognitive skill, and the problem of adapting cognitive tasks to make it fair for different species.

    1. Hey Riona, I had similar thoughts regarding the cognitive skill/behavior distinction.

      When we say that we are studying the evolution of cognitive skills by observing our close relatives, are we really just studying the evolution of behaviour?

      That's what it seems like to me. When the authors say “cognitive skill,” they are referring to a trait that produces a particular behavioral output to a particular set of conditions in a particular (albeit extremely contrived) setting. They suggest a direct correlation between this “tangible output” (Gorilla getting the sandwich) and the cognitive trait that can be inferred from this behavioral response (“inhibitory control”). So we are able to study the evolution of cognitive skills by studying the evolution of behavior.

      If I can do Task X, and my closest phylogenetic relative can do Task X too, there’s still no way of seeing how similar our patterns of cognition are.

      At first, I thought so too. But the more I think about it, the more the other minds problem pops into mind head. You're right, similarities in behavioral output to a particular set of conditions do not guarantee similarities in cognitive patterns. However, I can never know if the Gorilla is thinking/feeling, I can only infer it is doing so based on the way it behaves. And if it responds to certain conditions the same way I do, it would be reasonable to conclude that it thinks/feels just like I do. While there is indeed “no way of seeing how similar our patterns of cognition are,” there is reason to believe those similarities do exist. Maybe someday we will be able to elucidate these similarities, and comparative phylogenetics seems to be an excellent step in the right direction. You really hit the nail on the head in your last paragraph:

      However, the above grumbling is not to say that I’m throwing out phylogenetic measures to study cognitive evolution.

      While I had my issues with this article as well, and certainly don't think phylogenetic measures are the only tool we need to tackle the field of cognitive evolution, they do appear to be powerful techniques with impressive methodology that will be a key component of empirically testing hypotheses regarding the development of cognition.

    2. Hi Alex!

      Thanks for your response! I definitely agree with the other minds problem you mentioned. I think my argument maybe looked like I was unfairly picking on evolutionary psychology when of course all cognitive science/psychology are also faced with the other minds problem. For me, its just that evolutionary psychology has a nasty record of (as Professor Harnad said said) stepping way over the boundary into the ridiculous, dangerous, and harmful application. But you're totally right, just because we can't know for sure what the cognitions of any other living organism consist of, doesn't mean we should just drop all inference and abandon the field!

  12. This paper was interesting in its introduction of methods to understand the evolution of cognitive abilities in a phylogenetic framework, a topic I have never come across before. Differing from the previous paper, the authors dissect more simple behaviors that can date back to human’s ancestral past, attempting to distinguish a point in which humans diverged in their cognitive capacities from other similar species. The previous paper, instead, analyzed evolution within a single species. The MacLean paper was a refreshing read after the evolutionary psychology in 7a because the author’s analysis implicates that evolution is a slow process, one of which that can take up to a million years (or longer). Our species has only existed for an estimated 200 000 years (I don’t know how accurate this is) and as a result, when studying evolutionary psychology within humans, one has to be aware that the evolutionary process on cognitive behaviors can take hundreds of thousands to millions of years, as it does on any other attribute. This is something that the Confer paper doesn’t consider and fails to mention. By studying cognitive capacities of our ancestors in a phylogenetic framework, MacLean et al demonstrate the understanding that evolution is slow and if we are to discover distinct human cognitive capacities, we must identify divergence far back in time in our lineage just as evolution requires.

    “Having made progress toward revealing the development and causal mechanisms of problem-solving skills in animals,”

    Lastly I just wanted to comment on this observation made in the conclusion. When the authors reference “animals” I hope they do not refer to humans. This is humorous in the context of this class as we have learned that we know very little about the causal mechanisms of how we do what we do, and this observation is suggesting that we have made enough progress towards this that we can now revert our attention elsewhere.

  13. “The first two questions concern the ontogeny and causal mechanisms of cognition and have been the focus of comparative psychology since its inception“

    “Having made progress toward revealing the development and causal mechanisms of problem-solving skills in animals, we are now in a position to quantitatively examine Tinbergen’s other two questions for biological analysis”

    Throughout the article the authors are eagerly discussing potential new methods in comparative biology that can be used to aid comparative psychology. But I’m not sure that (as per the second quote) the authors really have addressed the causal-mechanisms of problem solving skills. Although I can understand that tracking certain cognitive skills through phylogenetic history can be beneficial for understanding which species have certain traits, I don’t think this provides any insight into the mechanism of how these traits work. For example, understanding deceptive behaviour in chimpanzees may demonstrate that our closest living non-human primate relative also this social communication strategy for various reasons, but how does that shed any light on the mechanism? To me this is a poor attempt at answering the hard problem. The authors seem to suggest that if we find human “traits” or adaptations in animals we can understand the causal mechanism, but we can’t! As the authors frequently mention, the circumstances in which each species lives is unique and incomparable. Even if primates are using similar communication strategies to us behaviourally, there is no way to know if the actual mechanism is the same even if the behaviour is comparable.

    1. Hey Renuka,

      I definitely see what you're saying -- the authors seem to be extremely confident in these methods, but I have some ideas to share. When you say "For example, understanding deceptive behaviour in chimpanzees may demonstrate that our closest living non-human primate relative also this social communication strategy for various reasons, but how does that shed any light on the mechanism?" I think you mean that phylogenetic targeting doesn't tell us anything about the step-by-step neuronal process that ensues when the behavior takes place, correct? I agree with that, but maybe instead there is something worth examining for example in comparing the brains of chimpanzees and humans or imaging the brains of chimpanzees and humans as these behaviors are studied. I know it's easy to criticize something like this (believe me, I want to as well) but I think the point of this paper wasnt to prove the causal mechanisms of all behavior but it was to try to find clues that may help us get there -- or even just argue for trying to find clues. Maybe, the differences and similarities can shed some light on the mechanisms involved even if it doesn't give the clear picture at all. But that being said, I definitely agree that a lot of this paper was very eager to say that these are remarkably novel ways of understanding things, but it's clear that there are limitations and huge issues with drawing conclusions based on phylogeny. I do think the authors are right though in being confident in phylogenetic targeting because that allows for specificity in research, though again, this isn't telling us anything about what's really happening inside of our heads.

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  15. I wonder about the possibility of ‘convergent evolution’ of cognitive traits, where phylogenetically unrelated species come to develop similar traits at different points of time. Octopuses, crows and apes are all cognitively advanced in their own right, yet they are only very distantly related. In particular, what can the manner and order in which certain traits emerge within different evolutionary trees tell us about their nature? The question that interests me is really about the modularity or integration of different cognitive abilities. Say we find that a certain capacity B always emerges after some other capacity A when it develops in genetically independent species. This might be a hint that something about capacity A—or whatever underlies it—is required for or at least facilitates capacity B. If we can really map out a general trajectory that cognition tends to follow over time as it develops, it would give us a much better grasp of what it means to be ‘cognitively advanced.’ On the other hand, if there does not seem to be any necessary ordering or trajectory to the development of specific capacities, it might be a hint that they truly are modular and that intelligence is better viewed qualitatively than quantitatively.

    1. I think this is a lot of what Phylogenetic comparative psychology tries to do. For example, we know that there are simpler language systems and simpler muscle systems (ie old area M1 vs new area M1 for individual skilled movements) that are present in our closer relatives. Our own cognitive systems have built on these and so by finding simpler systems in our relatives that are similar to our more complex systems, we can attempt to understand where ours developed from (B from A). I think intelligence has to be viewed both quantitatively (because there are clearly varying degrees of it) as well as qualitatively (because there are many different types).
      What makes one type of intelligence qualitatively superior to another though? This reminds me of Einstein’s’ quote: “we’re all geniuses but if you judge a fish on its ability to climb a tree it will live its whole life believing it is stupid”. I think the way each animal think is tied to their environment and survival needs.

  16. “Here, we provide an example of phylogenetic targeting using the example from above, in which we detected a trend (P = 0.06) for species with relatively larger brains to exhibit better performance on the cognitive test of inhibitory control (incorporating variation in body mass and phylogeny).”

    While I am fascinated by the concept of using phylogeny to “prove” aspects of evolutionary psychology, I am finding difficulty understanding the purpose of Phylogenetic targeting, or at least this example of it. From what I understand, they are trying to find a relationship between the size of the brain and inhibitory control. I think that modern neuroscience has already answered this question, and that parts of the Prefrontal Cortex are involved in inhibition. What are we gaining by asking if it is the increase in cortical matter? We should be asking which parts of the cortex specifically are more active, and larger does not necessarily always mean more active. Shouldn’t we be more specific than just looking at brain size? Is this possible?

    “In contrast, phylogenetic targeting indicates that Callithrix jacchus—another species readily available for study—offers a far superior contrast in brain size as reflected by the much higher summed score (0.43). If the researcher wants to add a single New World primate for comparison to Cebus apella, then Callithrix jacchus provides more statistical power than Saimiri sciureus.”

    I understand that the statistical power of two species close in brain size is low, but if we are comparing species with a larger difference in brain size, couldn’t they have other differences in brain morphology and function that could account for behavioural differences?

    “Should these species be directly compared using the same task? If the researcher concludes not, the targeting process could be performed again with additional inclusion criteria to generate the pairs. For example, pairs could be restricted to species with the same activity pattern (i.e., diurnal or nocturnal) to avoid pairing species that likely differ greatly in their visual acuity (particular pairs can also be eliminated manually). Because phylogenetic targeting allows users to focus on the variable of interest, while simultaneously controlling for other potential confounds or testing constraints, it confers flexibility and statistical power for designing comparative tests.”

    One last misunderstanding of mine regarding phylogenetic targeting, involves the confounding variables. How exactly are users “focusing on a variable of interest”? How does this eliminate confounding variables like differences in the tasks?

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    1. Copying and pasting my skywritings for the mid-term and noticed this comment was published twice by mistake. Sorry!

  18. Firstly, I don’t think it is reasonable to compare cognition across a wide variety of species in order to conclude a general model of ‘cognition’. It seems to me like its comparing apple to oranges. Every species has their own neurochemistry and it seems like scientists are looking for observations to already conclude their pre-made assumptions, a term in psychology known as the self-fulfilling hypothesis. Especially comparing non-humans and humans, if we are looking into the cognition of humans from an evolutionary standpoint, wouldn’t it be best to focus on their evolution? As a result, I don’t think there is a way to come up with general process cognitive models to cover a range of species if they are all so unique with their differences.

    Secondary, although the article identifies some key terms, it fails to define some of the more important ones such as “Phylogenetic Comparative Approach” which is emphasized throughout the article.

    Thirdly, the article states that “increases in social complexity drove the evolution of cognitive flexibility in primates”. However, it fails to give a quantitative measure for ‘social complexity’ therefore isn’t it hard to compare it and conclude its correlation to cognitive flexibility? Social complexity seems like a large umbrella that can consist of a range of complexities; therefore doesn’t it seem too broad to draw any specific conclusions/assumptions/correlations?

    Next, the article compares evolutionary history to body mass. I don’t think this is a safe comparison at all; there are many other factors which can contribute to body mass such as genetics, disease, environmental issues and personal circumstances; which might divert from evolutionary circumstances.

    The article states that the field is focusing on a large number of hypothesis drawn from a small range of species. As a result, there isn to enough concrete evidence to form solid conclusions; it seems as if there is still a lot to be researched.

    1. Hi Rachel,

      1. While I do agree that a “general model of cognition” across species is unlikely to come to fruition, I believe that the authors were more focused on learning where in phylogeny and when in history cognitive capacities across species may have evolved. Thus, the phylogenic comparative perspective seems to be in contrast with the model species approach “from which they aimed to develop general process cognitive models” (3). In this regard, that is why most research focuses on our nearest relative i.e. apes/monkeys (as we evolved from them) to figure out the interspecific variation. I believe it is important to look into the phylogenic history and function in order to assess why certain lineages have evolved various cognitive capacities. However, I am still unconvinced about if this method can help us explain how cognition arises. Even more, I do not believe that the entirety of cognition is bound by evolutionary influences.

      2. Phylogenic comparative approach incorporates several methods in comparative psychology and evolutionary biology that they go over in the ‘Phylogenic comparative methods’ section. Also Figure 1 gives the overview of which method is used to answer relevant evolutionary questions.

  19. In this article, it is interesting how the process of evolution places humans as the most evolved species because they tend to perform better on tests that they designed themselves.
    One of the commonly given examples of cognitive evolution is to be able to recognize oneself in a mirror. However, with this example, it is worth questioning how much of it is being intelligent and determining that it is you in the mirror and how much of it is observation? Does having more exposure and therefore being more able to perform the task properly make a specie more intelligent. I am sure young children do not understand that it is them in a mirror before a decent amount of observation and explanations coming from adults. There have been no studies examining if they could figure it our totally on their own (I understand that these studies would be unethical). Despite this, animals (more precisely apes) in our discussion, are expected to understand this on their own without prior exposure or explanations.
    The example presented in this paper is the ability of apes to repress a prepotent motor response. The authors go on about how the laboratory setting can be controlled by analyzing apes of the same species in different laboratories in order to control for the laboratory settings these apes are brought up in. Nothing is mentioned, however, about the possibility of the apes experiencing a similar situation or a barrier in their natural settings. For example, if the apes were more likely to find a similar transparent barrier in their natural settings then they would find the situation more familiar and would know better how to react (know that their hand cannot cross the barrier) than animals who do not see similar obstacles in their everyday settings.
    In writing this, I think I am confused about the meaning of intelligence. I assume it means the ability to categorize things appropriately and come to conclusions and appropriate actions to respond to these things. However, I do not know if having prior exposure and instructions on how to react in certain situations and therefore responding appropriately without inferring your response on your own makes an individual intelligent. The concept of functional fixedness further supports that fact that this cannot be considered as intelligence as in its presence individuals are unable to respond appropriately to given situations because they tend to ‘’obey the rules’’ rather than reacting properly.

  20. I too had a difficult time integrating and understanding the concept of comparative phylogenetic psychology. The whole concept of analyzing the cognitive behavior patterns of species and integrating them in order to approximate the cognitive patterns of the node common ancestor seems to make sense. (If the concept is viable), it informs on the past and present states of cognition, and on the environment because it plays a strong role in shaping cognition (i.e. cognition evolves based on environmental stimulus). But it doesn’t give any information as to why the changes from ancient to current state occurred. Furthermore, cognition being so intricate, is it realistic to just say that environment is the only thing that shaped it? Couldn’t there be other important factors involved in the evolution of cognition? Especially because there are cross-species common cognitive traits, while the species themselves live in strikingly different environments. Therefore cognitive evolution might not just be the sum of environmental experiences…

  21. I think that the method of phylogenetic comparative psychology presented by the authors is interesting and an idea to understand the evolution of cognition. However, I agree with Alex in that the notion of quantifying cognition seems problematic, partially because of what Rachel said in the first paragraph of her comment (though I think I have a different take on the matter).

    The issue for me is that 'traits' like cognition are quite abstract, thus more difficult to arbitrarily measure. Furthermore, cognition is multifaceted and variable within our own species. No denying that our cognitive capacities are related to the cognitive capacities of other species however, it is much simpler to quantify and analyze distinct physiological changes with comparative evolutionary analysis (e.g. differences in visible traits like differences in skeletal shape or cortical structure). I feel that it would be more beneficial to look at correlations between morphological traits such as the structure of the cortex and connectivity of the brain to understand differences, rather than things like body mass and brain size, which the article appears to focus more upon.

    Also, though I know that the next section has to do with language, the fact that our species cognition is entrenched in language and, since language is unique to our species as well as a pervasive facet of our cognition, I find that there may be some limits to the extent to which we can accurately trace the evolution of our cognition. This review article talks about an interesting study by Laura Anne-Pettito, which looks at the gap between humans and chimpanzees due to language and lack there of. I feel that the study may tie back in with the topic of categorization:

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  23. "One of the main goals of comparative psychologists is to document variation in problem-solving abilities across species to reveal the processes by which cognition evolves."

    I can't imagine that phylogenetic comparative methods could ever actually document the way that cognition evolves/has evolved. It seems to me that in order to do that you would need to be able to look at the brain of species that immediately preceded us, i.e. the Neanderthals, but of course since they have become extinct this is not possible. Otherwise I think you would have too much or an evolutionary "jump" (i.e. in comparing human brains to chimpanzee brains). You have inevitable gaps when attempting to establish the evolution of cognition. I think if you could look at and compare human and Neanderthals brains you could note structural differences and infer functional differences. That being said, cognition is more complex than that, and problematically, much harder to quantify. Perhaps not knowing exactly what cognition is or how to measure it should impede us from making any concrete observations about its evolution.

  24. • “Thus, one major challenge is for comparative psychologists to develop dependent measures that can meaningfully be interpreted as traits. In some rare cases, it is possible that performance on a single task may meet this criterion. However, in many cases it is domains of cognition rather than performance on single tasks that is most interesting for comparative analysis (11).
    With this quote it really bothers me that there is no definition of domains of cognition. Isn’t all testing we do trying to generalize from a result to a potentially greater effect that we can then go on and study? I remember learning about ecological validity in my first psychology class and it made sense then and it makes sense to me now – in most cases you are trying to use a single behavior to indicate a greater effect, however subtle the ways that measuring and manipulating that one behavior might be. I also am not sure I agree with the fact that “domains of cognition” should be more interesting to a comparative psychologist than single task behaviors – to me it seems like the more fine-grained the difference the more it can tell us when you compile across all of those differences in whatever the tasks are (like Attention, or whatever they mean by domains of cognition). It seems to me that the argument they are making is essentially “cognition is greater than the sum of it’s parts.”

    “By adding phylogenetic techniques to our tool kit, comparative psychologists can build on past success by incorporating tests of correlated trait evolution, phylogenetic signal and ancestral state reconstruction into our research.”

    I do think that phylogenetic techniques are really useful in trying to prove hypotheses. I remember taking a class in Evolution & Behavior in New Zealand with a professor named Russell Gray. He published a paper on a “Pulse Pause” model of the spread of language in the South Pacific.
    If anyone is interested in the evolution of languages this might be of interest:

    [THIS IS TANGENTIAL] He also talked a lot about the “hand to mouth” hypothesis of how humans developed language, which we touched on briefly in class once I believe… These center around gestural theories, which say that communication used to happen through gestures only and eventually turned into vocalization. Corballis thinks that our ancestors started to use tools and then because they couldn't use their hands to communicate effectively anymore they had to start vocalizing, also if you are occupied using a tool it is better to use audition rather than vision

    In any case, I do not know how I feel about evolutionary psychology now. I really hated the other article and the other things that Busson has done but I can see the value in using these methods as ways of figuring out the how we got to getting cognition , but I still think that there are often leaps of intuition that happen in evolutionary psych (paternity jealousy theory) that are troubling.

  25. Initially as I read through this article, I was very skeptical on how phylogenetic comparative analysis could be conducted at the species specific level in terms of cognition. However, the quote “In some rare cases, it is possible that performance on a single task may meet this criterion.
    However, in many cases, it is domains of cognition rather than performance on single tasks
    that is most interesting for comparative analysis” helped to clarify, when the article began discussing cognition as a trait, the importance of collaboration, and the necessary methodology that would need to be incorporated.

    I find articles that stress the value of collaboration in a meaningful and standardized way, such as this one, to be extremely important, as time and time again in various psychology and neuroscience classes, the subject of comparative ability is addressed. While we learn the importance of reliable and verifiable research, not enough stress is given for comparative ability to other studies. While this becomes exceptionally important in the field of comparative psychology and the evolution of cognition, the standardization ideas proposed hear would be beneficial to more than just this branch of psychological research. Meta-analyses often have to stretch to great lengths to great a valid comparison, or of a sample size of 500+ relevant studies, will be able to siphon out maybe 50 that are comparable in their data. This seems like a huge waste of time and effort, as well as resources. Especially in terms of animal testing and harm (which you will be pleased to know that this class has made me more and more conscious of), creating networks of standardized collaboration for scientists in a manner that it also doesn’t infringe on a researchers area of study would greatly improve the efficiency of the field at large.

    The other reason I liked the quote above is it dismantled much of my skepticism that I initially had regarding cognitive assessment of animals for evolutionary psychology. Using multiple tests to determine a trait and its meaningful interpretation as well as possible variation is a much more reliable way to establish what theorists should be looking for, since, as the article states: “Cognitive performance does not fossilize” and “one cannot directly measure the traits of extinct species”. The use of phylogenetic information for this type of study is well argued in this paper, and has left me feeling as though it is indispensable to the study of evolutionary psychology.

  26. “Without recourse to questions of phylogenetic history and function, we cannot understand how or when species evolved to differ cognitively. Moreover, we cannot test why certain lineages—including humans—have evolved the cognitive abilities they possess.”

    This brings up an important question I honestly have never full thought through. Humans claim to be separated from the humans for their ability to think, but why did we get to evolve this way? And I don’t think we can imagine we are the only one. What makes something evolve if it is not maladaptive? We have quantitative measures such as brain size (cc), which fall relatively flat in their explanatory abilities once we broach the complex field of cognitive function. Which field do we pick to follow in order to find an evolutionary tract of cognition, and that being said, is this even possible? We have so many threads to pull it seems overwhelming. This also brings out the importance of testing things today for looking into the future.

  27. Let’s talk about crows for a second. Crows are so cool. They can engage in analogical reasoning without training: They can spontaneously use tools… to retrieve other tools: They understand the dynamics of water displacement: I’m disappointed that MacLean didn’t talk about them because most people I talk to about the sheer awesomeness of crows are quite surprised. Counterintuitively, it may be more informative to study the evolutionary history of crows to discern the origins of their intelligence than it is to study our closest primate relatives. Because we have less in common with crows, the similarities should stand out in sharper contrast.

    1. Hi Brad!
      I agree with you that crows are intelligent and it could be interesting 'to study the evolutionary history of crows to discern the origins of their intelligence'. However, I think crows are just too different. Truthfully, I do not know very much about crows, but for a starter, if you look at a crow's brain, it doesn't seem to have sulci and gyri like human and primate brains do. As well as different brain regions exist in crows but not exist in humans and vice versa. So, I think humans and crows would just be too dissimilar. I think that the sharp similarities you mention would be sharp similarities that any mammal and human share.

  28. I found this paper to have a more comprehensive approach than the paper on evolutionary psychology (7a) on the connection between evolution and cognition. However, in Maclean's paper, I found there to be a lack of focus in human cognition. Granted, the phylogenetic approach compares phylogenetically related species, but in order to gain a "better understanding of the evolutionary processes that gave rise to the human mind," should we not look closer at the course of human evolution?

  29. I’m confused as to why the authors would examine whether phylogenetic methods can quantitatively test whether specific cognitive abilities are correlated with morphology/brain size when they refer to the dearth of scientific support for any such relationship? The authors write “Empirical evidence suggests that there is no one-to-one relationship between cognitive flexibility and brain size”. While I think phylogenetic distributions and comparisons can absolutely be a valuable tool in understanding the biological origins of human cognitive capacities, I do not think that studying brain size is going to yield valuable answers to psychology’s big questions about how cognition arises.

  30. My first question is about when the authors are talking about the social complexity experiments. They discussed it quickly and mentioned that social complexity drove changes in non-human cognition. I wonder if the authors are warranted in using the word drove, if it’s possible that we’re only talking about correlations. To me, it seems possible that either factor could “drive” the other factor. I know this is only the review part of the article, but I would appreciate clarification about when they use that word. I think it’s important to the point of the article if those experiments found causal mechanisms explaining the how or if they merely pointed to an association of factors.

    Secondly, I find the idea that cognitive flexibility animals could be related to brain size to be laughable. I think we’re dealing with a few assumptions in this claim, here. One is that it seems to point towards the domain-general approach, in that one particular cognitive variable would be so representative of all cognitive variables. The second assumption is that brain size has any kind of correlation with function, especially at the domain-general level. At a domain-specific level, I think we can point to examples (for instance: sensori-motor cortex). But, it’s not like smart people have bigger heads. Definitely can’t think of a meta-study showing a link between IQ (Spearman G) and overall brain size, weight, volume… whatever. That’s like phrenology territory.

  31. While this article is far more articulate than 7a) (evolutionary psychology) because it offers an exploration of a more or less method/framework of approaching evolutionary cognition, it nevertheless also appears rather premature, because there appear to be more uncertainties about phylogenetics than anything else when exploring its merits in the field of (evolutionary) cognition. The authors are very clear about the pragmatic limitations in using this framework, such that while it would be ideal to build "large datasets across a diverse range of species," (10) they must stick to" collecting data on fewer species that provide stronger tests of a particular hypothesis and better control of confounding variables and alternative hypotheses"(10) with the assumption that the authors will simply extrapolate their findings onto animals part of much larger groups of organisms (such as primates for example). This is all operating under the rationale that "we understand how cognition evolves in nonhumans, this knowledge may in turn inform our understanding of how our own species’ cognitive abilities have evolved" (3). Frankly, phylogenetics appears to be a framework in conceptualizing and exploring the 'big picture' of evolutionary cognition, because of the amount of 'guesswork' and extrapolation it relies on, and especially because the overwhelming majority of data that would provide context for present day findings are dead.