Does Our Paleolithic Past Shape Our Modern Survival Instinct?

The latest National Geographic Roundtable Question: Survivor-style television has grown increasingly popular over the years and done a great job of illustrating our brain's fascinating built-in survival instinct. What role do you think our ancestral instincts play today in helping us survive, thrive and accomplish our goals? How much of our ancestral survival instincts are innate verses learned?

First, the innate vs. learned part of the question. This is a false dichotomy. We have evolved to learn. We probably have "built in" mechanisms to learn new things. This means that when we have learned something new, that new skill or information is a product of something innate and something from our environment. (See: Culture Influences Brain Function and IQ Varies With Context.)

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National Geographic Channel's Brain Games: The Survivor Brain premieres Sunday, March 20, at 9/8c on National Geographic Channel

In this episode, host Jason Silva meets several people in Colorado Springs, Colorado, who personify the word “survivor,” and puts their brains to the test in a battery of challenges engineered to demonstrate what it takes to be a super survivor. The group gathers to deconstruct the brain science behind human survival: how we evolve to survive and what role our ancient instincts play today in keeping us alive … or getting in the way. Neuroscientist Dr. Bart Russell from Lockheed Martin tests one group’s cognitive performance under stress. Dr. John Huth of Harvard University, who wrote a book on how to find our way when we are lost, tests the brain’s ability to remember details. Dr. Alex Jordan of the University of Texas puts the survivors to the ultimate test, but they’ll have to accept that the key to surviving may be a collective effort. We learn common characteristics of survivors — whether hardy or fragile — and discover what can be done to tap into the brain’s built-in survival instinct.

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The degree to which this is important should not be underestimated. Humans pay a high evolutionary cost for this ability to learn. We have developed over evolutionary time a mostly novel stage of development that we call "childhood" during which we are vulnerable and demand a great deal of parental investment, far beyond our nearest primate relatives. Childbirth in humans is dangerous to both mother and child compared to other mammals, and this is in large part because of our large (but mostly "empty" brains at birth. Childhood involves the internal organization of that brain due to experiential learning aided by built in learning mechanisms. This takes years, and results in a young adult adapted not to our paleolithic past, but to our current cultural environment. (See: The Oystercatcher and the Clam)

In other words, we are adapted, by evolution, to be adaptable to the particular context in which we live. For this reason, our actual (in the sense of current, now) set of survival skills are adapted to the present because we are shaped by evolution to be able to do that.

Having said that it is still true, as demonstrated in the National Geographic special, that we are products of our past. We are endowed, for better or worse, with automatic reactions to the environment such as the stress reactions and the famous "four F's" of fighting, fleeing, feeding, and sex. Our learned abilities incorporate these basic limbic (brain and endocrine) functions, but these functions are powerful and often produce less than ideal results.

There is a debate in evolutonary psychology and related fields over the degree to which specific abilities, including survival abilities, are shaped mainly by our paleolithic past vs. our cultural and more immediate developmental past. An example that is sometimes used is the bartender vs. file clerk test. Here's how that goes, simplified.

Several subjects are given this problem. You are a file clerk and you go on vacation for a time, and a temp takes over your job while you are gone. On your return you have the sense that the temp messed up some of your files. You are faced with a set of labeled folders that may or may not have been filed incorrectly. Your job is to open the absolute minimum number of folders to test the hypothesis that they are correctly filed. there is in fact only one correct answer to this question. A majority of subjects fail to arrive at the correct answer.

Alternatively, several subjects are given this other problem. You are a bartender and a specified number of people (the same number as filed in the previous setting) are sitting at a table in your bar asking for various drinks. Some of the drinks contain alcohol, some don't. You suspect one or more of the individuals sitting at the table are lying about their age, so you need to ask for ID. Your job is to ask the absolute minimum number of people for their ID. There is exactly one answer to this problem, and the underlying logic (and answer) is identical to the file clerk problem. A majority of subjects arrive at the correct answer.

Those who put a lot of stock in our brains being shaped by our paleolithic past believe that this is because we evolved in a context where identifying liars is important, so we are innately good at that, while file clerking is a modern endeavor, so we are not evolved to be good at that. The alternative explanation is that we each grew up, as cultural beings, in an environment where learning to detect liars is important, so we got good at that, but very few of us grew up as file clerks, so most of us are bad at that.

I personally lean towards the latter, and I look at the costly trait of childhood as the mechanism by which this situation emerges.