My main question wasn’t about how evidence is biased via perception, etc. Rather, I was wondering how overloading of working memory is understood at the neural level, particularly in the context of decision-making. In other words, I’m wondering how information-loss functions at the neural level.

More generally, why is there a limit to short-term memory, even outside of decision-making tasks (e.g., Miller’s 7 +/- 2 result)? What happens to the information neurally, how does it just ‘disappear’?

Is it a lack of necessary pre-existing synapses, so that some firing patterns just hit dead-ends? Or some sort of signal attenuation when there are too many firing patterns competing for shared resources?

Maybe I should just read the book, huh?

Mathphysto – You are asking fascinating questions. Contrary to popular belief, emotions play an essential positive role in decision-making. As I have written in Welcome To Your Brain, emotions tell us when an event is important, positive or negative. When people have brain damage that impairs their ability to link emotion with higher processes, they become horrendously indecisive. It’s fairly well understood – read my book! Of course such a mechanism can be overactivated.

In regard to biases, there’s no such thing as unbiased integration of information. All information comes in against a backdrop of prior evidence. These “priors,” as they are called, guide us to accept some evidence more than others. This is essential for survival in the natural world.

In political decision-making, there’s no feedback that corresponds to survival. Voting for Democrats or Republicans doesn’t get you eaten, mostly. Even when you vote for a party that drives the economy into the ground (or allows the U.S.S. Cole to be attacked, or whatever your favorite bad event may be), it wasn’t your personal doing. So biases stick around.

What about errors in the decision-making process? Specifically, what is happening neurologically when a voter decides to support a candidate that they mistakenly believe agrees with their own views on several issues?

I’m thinking in particular of cases where cognitive overload leads a voter to forget a candidate’s platform/past record on some issues when integrating the evidence to make a decision. Many people make their decisions without writing down the evidence and organizing it in a systematic way, so there seems to be plenty of room for such errors. Who can easily juggle evidence on a few dozen major multi-faceted issues to make a decision that optimally represents their own intrinsic opinions? Seems like it would easily exceed the short-term memory abilities people have.

Do the neural patterns corresponding to certain pieces of evidence just ‘drop out’ from the decision-making process? Or maybe there is some sort of piece-wise evidence integration process that starts with a decision based on one ‘chunk’ of evidence (perhaps the most important), then adds another chunk and ‘recalculates’ the decision, and repeats this process until the evidence is accounted for? Essentially like a finite series starting from a zeroth approximation, then adding a first, second, etc, until you get the final result.

Relatedly, do you have any idea about the degree to which emotion can alter the decision-making process? My intuition says it would be able to cause evidence to be (a) re-weighted (a special-case of this being ignorance, i.e., zero weighting), and/or (b) altered in perception/interpretation. But I’m not sure how well the neural end of this is known.

If you see this elsewhere, it was posted in error, it is meant to be here.

More often than not, when I asked undecided voters what issues they would pay attention to as they made up their minds I was met with a blank stare, as if I’d just asked them to name their favorite prime number.

http://www.newyorker.com/humor/2008/10/27/081027sh_shouts_sedaris?printable=true