Author Topic: The Cognitive Tradeoff Hypothesis  (Read 498 times)

Offline Vetus Ordo

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The Cognitive Tradeoff Hypothesis
« on: May 12, 2019, 11:04:01 AM »
The Cognitive Tradeoff Hypothesis

Itís clear that animal species have different skills and talents that are appropriate for their niche in the environment. Every animal has a limited amount of brain power and size, so every skill and talent has an opportunity cost. This is not controversial or particularly questioned.

The Cognitive Tradeoff hypothesis is about tradeoffs apparent between chimpanzees and human, because it speaks directly to who we are as a species. The evidence suggests that chimps have a much superior short term memory relative to humans. I wonít try to explain the magnitude of the difference, but the video reference shows it well.

The CT hypothesis suggests that losing short term memory is one of the costs of our entering a new environment, the savanna, with different challenges than were faced by chimpanzees, who stayed in the forest. The hypothesis is that our language facility was developed at the cost of short term memory, and that language (and the symbolic thinking that accompanies it) were more valuable to us than memory. Dr. Matsuzawa gives excellent reasons why that might be so.

While there is a lot of truth and insight in the hypothesis, there are some problems with it, and Iíll introduce you to them.

  • We have three times as many neurons as the chimp, so there wasnít necessarily a need to lose anything to get our new facilities. That doesnít preclude an evolutionary bottleneck that did.
  • What the video evidence shows is short term memory, which in humans is mediated by the limbic system, not the cortex. Only with consolidation does memory migrate to the cortex. The limited resources there might be the source of the tradeoff, but again, our larger number of neurons might have mitigated the tradeoff.
  • The recent evolution of chimps and humans have been in completely different environments, with different survival needs, so the difference might be adaptive rather than a tradeoff.

The last item is what I want to say more about. One of the biggest differences between chimps and humans is their level of socialization. Chimps live in small clans with rigid hierarchical social networks. In such a social environment, tiny details can be major factors in maintaining social survival of the individual and even the group.

Humans have a much more open social structure, and we have successfully(?) proven our ability to live in crowded cities of tens and hundreds of thousands. I propose that doing so requires weaker short term memory. Another tradeoff that wasnít discussed is that we dedicate enough memory in the Fusiform Face Area in the right hemisphere to differentiate and remember hundreds of human faces, something a chimp has never needed. Carefully remembering all the slights and injustices each of them perpetrated on us would not encourage social cohesion.

I like the Cognitive Tradeoff hypothesis, but we donít have to adopt every hypothesis that we like. Scientists tend to hold marginal hypotheses in reserve rather than accept/reject them. They may prove useful in the future.
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Offline Kreuzritter

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Re: The Cognitive Tradeoff Hypothesis
« Reply #1 on: May 14, 2019, 05:25:08 AM »
When people telling untestable just-so stories pretend they are conducting science ...