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Adaptations for Foraging & Spatial Cognition

Finding food is about as important and recurrent an adaptive problem as there is.  In the human case, our ancestors made much of their living by gathering and processing a wide variety of stationary, mostly plant-based resources.  To be successful gatherers would have required many systems of specialized neurocognitive adaptations: a visual system capable of perceiving a wide array of potentially gatherable objects, a gatherable object categorization system, a system of knowledge about gatherable objects, a motor system capable of implementing the physical processing required to extract the value from gatherable objects, etc.  In this research line we focus on the suite of mechanisms that enables learning the location and characteristics of gatherable items, remembering these details, and later deploying them for the purpose of efficient navigation back to the items’ locations.

What should an efficient mechanism for ancestral gathering look like?

From first principles, and from a basic assumed structure of our ancestral past, several first order hypotheses about the design of the gathering mechanism can be made.

  1. The gathering mechanism should be activated by (or receive input from) cues of gatherable resources in the environment
  2. The gathering mechanism should privilege high benefit/cost resources (due to differences in caloric density, handling requirements, etc.)
  3. The gathering mechanism should have a low level of chronic activation, which can be supplemented in motivated conditions
  4. The gathering mechanism should encode the location and characteristics of the items whose representations activated (or were input to) the mechanism.  The location should be encoded within a holistic spatial representation, such that from novel locations within the representation direct vectors can be inferred back to the location of the resource
  5. The gathering mechanism should be more active in human morphs (sex morphs or life-stage morphs) for whom gathering was a more important activity than it was for their counterparts.

Evidence so far:

Over a series of studies, we have started to validate many of these hypotheses.

One study documents a reversal of the usual male advantage at real world navigation when the content of the objects to be navigated to is gatherable plant resources.  This finding provides evidence for hypotheses 1, 4 and 5 above.  Additionally, both men and women in this study demonstrated more accurate navigational memory for higher caloric density foods, providing evidence for hypothesis 2.  These findings were observed even when controlling individual differences in general spatial ability, experience with the particular environment, liking of the food items, etc.

This study was published in the Proceedings of the Royal Society, Biological Sciences, and can be accessed here: PDF

Press coverage of this study includes pieces by Science, The Economist, and The Daily Telegraph

The Science coverage prompted a letter from Brumfiel, Di Leonardo, Hoffman, Kuzawa, McDade, Schwartzman and Seligman (Northwestern University, Anthropology Department) that was critical of our paper. 

Our response to Brumfiel et al. was published by Science along with their letter: PDF

Unfortunately, several unapproved changes were made to our letter after we approved the proofs and were published in the print edition of Science.  Our intended letter of response can be accessed here: PDF.

One issue in specific we feel most especially needs to be addressed.  In our actual response we made the argument that the human sexes differ in a number of ways, and that any attempt at egalitarian policy must be mindful and informed of these differences to be effective.  We characterize Brumfiel et al.’s claims of biological identity as a weak commitment to egalitarianism in name only that is in fact counterproductive.  Unfortunately, the letter as published makes it sound as if we are not committed to egalitarianism, which is absolutely not the case.