Tuesday, February 21, 2012

Why smart people behave stupidly

People are ruled by habits, good and bad. We are slaves to routine. We make knee-jerk assessments instead of thinking things through. We suck at probability and large numbers. We are easily manipulated by advertising. Small adjustments in the way things are framed can lead us into making completely different decisions. We persist in believing foolish things long after the weight of evidence makes their foolishness clear. We're complacent, ignoring serious problems until we can't avoid or deny them any longer.

This isn't just dumb people. People who are demonstrably smart do this too. And I figured out why.

Natural selection drove the human species to develop a big brain. The capacity to think is essential in outwitting bigger, faster, stronger competition. It allowed all kinds of things from social organization to tool use. There's a big but here, though. It's the capacity to think. The problem is that the brain is expensive. It accounts for some 20% of our energy consumption (at rest). Perhaps that was even higher back when we didn't get so many calories.

As a result, evolution favored humans who possessed big brains but avoided using them unless absolutely necessary. It favored big, lazy brains. Humans who were always thinking were always burning calories while rarely gaining by it. We evolved many cognitive shortcuts that resulted in inferior but good enough results at a much lower caloric cost. Smart people being stupid is basically millions of years of evolution. That's hard to fight. Maybe this will help me be more tolerant.

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5 Comments:

Blogger wins32767 said...

The caloric demands of the brain are fairly constant, it's not like muscle where there are dramatic shifts in resource consumption between fully engaged and at rest.

That said, attention fatigue is a real phenomenon, so there is a resource constraint at play. Several studies recently imply that willpower and focus are limited.

February 21, 2012 at 12:22 PM  
Blogger Ketan said...

Really? How do they measure that? Because MRIs and CT scans all operate on differential blood flow etc. to active parts of the brain. I find it hard to believe that this is constant.

February 21, 2012 at 2:32 PM  
Blogger wins32767 said...

Electrodes on the brain itself.

Money quote:
"The brain consumes a tremendous amount of the body's energy resources—it's only 2 percent of body weight, but it uses about 20 percent of the energy we take in," says Raichle. "When we started to ask where all those resources were being spent, we found that the goal-oriented tasks we had studied previously only accounted for a tiny portion of that energy budget. The rest appears to go into activities and processes that maintain a state of readiness in the brain."


Link: http://www.innovations-report.com/html/reports/medicine_health/brain_signal_persists_dreamless_sleep_119473.html

February 21, 2012 at 2:40 PM  
Blogger wins32767 said...

Hrm, the URL got truncated

Append this:

persists_dreamless_sleep_119473.html

February 21, 2012 at 2:41 PM  
Blogger Ketan said...

Quora discussion on the same topic says otherwise.

March 20, 2012 at 2:36 PM  

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