1:36pm Post your STAT questions here.
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2:14pm Psyc 112 -- The Evolution of Cognition
I think my attempt at explaining the evolution of cogntion was a bit foggy yesterday in class. Evidently sinus medications also reduce cognitive capacity.

Anyway, the capacity of our brain evolves and changes as our current environment changes. For example, the first hominids (those early upright walking apes) began to walk upright because the rain forests in Africa 5 million years ago began to dry up, so these apes that were used to foraging in trees (with no need to walk upright) now faced new challenges, and so walking on 2 feet became an advantage as these apes could travel greater distances to look for food. Being able to navigate across greater distances would also place greater demands on information processing and navigation. Combine this with a greater need for creativity in finding food with tools, and nature has placed greater pressure having advanced cognitive capabilities, and the brain grows.

Later in time, those early humans that could construct complex tools (spears) could more easily kill without injury to themselves. This gave them and their kin a fitness and reproductive advantage. Tool-making is a very cognitively demanding exercise, and so only those with slightly larger brains had this ability, and they were more likely to survive and attract mates, and pass on their genes. Thus, we developed larger and larger brains because those bigger brains gave us bigger survival and reproductive advantages.

Now this is the interesting part: Why can humans now remember 7 items in short-term memory on average?

Potential reason #1: the demands of our environment have put evolutionary pressure on brain size to be able to remember more information. So, the number of items capable of being remembered has been increasing in our evolutionary history and now we can remember 7 items on average. 7 is a good number for a short-term memory span. As the amount of information in our society increases, so too will our memory span. In fact, intelligence scores have risen significantly just in the past few decades.

Potential reason #2: the environment doesn't put direct pressure on having a higher memory span, but rather higher memory span is a by-product of other cognitive abilities. For example, some people believe that we have complex reasoning skills in order to detect deception in complex arguments (e.g., detecting "spin" in a political argument). Those who could detect deception would be better off because they wouldn't easily be duped. Such complex reasoning skills would require a highly developed frontal lobe capable of processing all this information. A by-product of this development might be that we're now able to remember more. That may not have been the direct consequence of evolutionary pressures, but as long as it's not disadvantageous, it will stay (like our appendix).

Hope this is more clear. Your Thoughts?

1:41pm Random thoughts go here
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1:38pm Psyc 112 Cognition comments
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11:13pm Visual Search in the News
So it turns out that this visual search research we're doing really does have real world implications. Jeremy Wolfe has a new article out in Nature this week modeling error rates in Airport Security screeners. I heard of this on NPR -- Jeremy Wolfe sounds exactly like Steven Pinker.