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Crows Outperform Pigeons and Primates in Learning a Basic Concept

24 Feb

A paper just published in Psychological Science:

Corvids (birds of the family Corvidae) display intelligent behavior previously ascribed only to primates, but such feats are not directly comparable across species. To make direct species comparisons, we used a same/different task in the laboratory to assess abstract-concept learning in black-billed magpies (Pica hudsonia). Concept learning was tested with novel pictures after training. Concept learning improved with training-set size, and test accuracy eventually matched training accuracy—full concept learning—with a 128-picture set; this magpie performance was equivalent to that of Clark’s nutcrackers (a species of corvid) and monkeys (rhesus, capuchin) and better than that of pigeons. Even with an initial 8-item picture set, both corvid species showed partial concept learning, outperforming both monkeys and pigeons. Similar corvid performance refutes the hypothesis that nutcrackers’ prolific cache-location memory accounts for their superior concept learning, because magpies rely less on caching. That corvids with “primitive” neural architectures evolved to equal primates in full concept learning and even to outperform them on the initial 8-item picture test is a testament to the shared (convergent) survival importance of abstract-concept learning.

The article’s conclusion contains this passage:

So, how did the apparently primitive bird brain that evolved from dinosaurs become competitive with, and even initially outperform, the abilities of what has been considered a more elaborate primate brain to perform abstract-concept learning, which involves thoughts and processes considered to be of the highest cognitive order? The answer most certainly lies in evolution itself, a multimillion-year process. Environmental pressures (social and otherwise) undoubtedly selected for and shaped these different neural architectures to successfully accomplish many of the same essential and intelligent behaviors for survival, an example of convergent evolution in which organisms not closely related (i.e., not monophyletic) independently evolved similar traits or functions as a result of having to adapt to similar environments or ecological niches. But the example of convergent evolution presented in the current study is comparatively novel and unique because its identification required special tests of the cognitive ability (trait) for the cognitive function of fully learning a same/different abstract concept to be revealed. Other examples of convergent evolution have been based on some obvious physical trait, such as wings, which typically can be identified from fossil records and have an obvious function of flying (some insects, birds, and bats).

“Does a taller husband make his wife happier?”

23 Dec

A paper published in Personality and Individual Differences. Here is the abstract:

“Although it has been known that women prefer tall men in mating for evolutionary reasons, no study has investigated whether a taller husband makes his wife happier. We analyzed two datasets (N = 7850) that are, together, representative of the Indonesian population to determine whether this is true. A greater height difference in a couple was positively related to the wife’s happiness. This relationship gradually weakened over time and entirely dissipated by 18 years of marital duration. The husband’s resourcefulness was a minor mediator in the relationship. We thus argue that the husband’s height and its correlates made his wife initially happy, but their influence waned over time. Nevertheless, the long period of the dissipation indicates a powerful impact of male height on women’s psychology, probably prepared by evolution.”


Gender equality and evolutionary psychology can co-exist

29 May

I was perplexed by this post in Slate: “Sorry, Evo Psych Fans. Our Caveman Ancestors Probably Practiced Gender Equality.” The first Paragraph reads:

“It’s a sad week for evolutionary psychology buffs. A new paper out in Science, by a group of scientists led by University College London anthropologist Mark Dyble, suggests that despite widespread claims to the contrary, early hunter-gatherer societies likely practiced equality between the sexes.”

Why does author Amanda Marcotte assume that evolutionary psychologists would be upset by these findings?

Evolutionary psychology is based on the assertion that human cognition is shaped by the same forces of natural selection that shapes our anatomy and physiology. This seems so obviously true to me.  A lot of attention is paid to the work of evolutionary psychologists on how human sexual behavior is shaped by selection, but this hardly exhausts the field. For example, as a developmental and educational psychologist I am very interested in why speaking a language comes easy to children, while learning to read is much more difficult. Or take the question of obesity, isn’t it plausible that there is a mismatch between our evolutionary propensity to seek high calorie foods and the food abundant environment that we now inhabit?

Moreover, there seems to be an epistemic-values confusion here. Gender equality is worthwhile goal and it should not be tied to any particular scientific finding. Suppose the findings Marcotte cites were overturned by later investigations? Would we then be required to abandon the struggle for gender equality? Of course not. We should strongly resist the is – ought fallacy.



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