There are 2 science-oriented podcasts that I really enjoy. One is The Naked Scientists(BBC) and the other is Quirks & Quarks(CBC). Both covered a study by a PhD-candidate at Duke, recently. The research concerned the influence of biology on risk-assessment.
Imagine this scenario: Monte Hall gives you $40. Then he tells you you can trade the $40 for a box. There's a 50% chance the box contains $70 (you gain $30). There's a 50% chance the box contains $10 (you lose $30). Risk is calculated as (probability of an outcome) x (value of the outcome). So, whatcha got he-yeh is:
1 x $40 vs [(.5 x $70) + (.5 x $10)]
$40 vs [$35 + $5]
$40 vs $40
in other words, the risk is equivalent. You can't make a rational choice between them.
So, this Duke researcher, Sarah Heilbronner, rounded-up some Chimpanzees and some Bonobos. Genetically, evolutionarily, taxonomically, whatever you call it, these are our closest relatives. She put her test-subjects into the scenario described above (1, 4, and 7 grapes, instead of 1, 4, and 7 10-dollar bills -- both species love grapes). She found that Bonobos choose the guaranteed 4 grapes, almost always (3 of 4 times). Chimps are almost as predictable, but in the opposite direction. Chimps prefer the gamble and big pay-off, Bonobos prefer the certain but lesser pay-off.
Of course, people try to understand from whence arises this difference. The best-received idea involves how each species obtains food. Bonobos have a very reliable food source. The fruit trees from which they eat occur regularly, both in space and time. Chimpanzees don't have that stability. For example, Chimps are hunters. Hunting, unless you have a shotgun, a bait-pile, and a deer population that isn't accustomed to predation, is a big risk. Chimps hunt Colobus monkeys in large packs. That means, if the pack doesn't find a monkey to kill, they all go hungry. They might go a long time without finding a monkey in a situation that allows them to kill & eat it. The thinking is that Chimps have a go-for-broke attitude. Having found a potential big meal, they'll go for it because their biology makes them suspect the small meal might not be enough to get them to the next meal. Bonobos' biology makes them think it's not worth risking a small meal to get a really big one -- after all, there'll be another decent-size meal along tomorrow.
Humans make the same choice as Bonobos, in almost exactly the same proportions -- almost 3/4 times. This is interesting. But, really, what it made me think about is Jared Diamond's work. (Guns, Germs, and Steel and Collapse).
One of his ideas is that humans didn't switch from hunting-and-gathering to farming because it was (as we tend to think) on obviously brilliant strategy for our species' survival. In fact, hunter-gatherers spent less effort acquiring food, ate a more diverse diet, and starved far less frequently than early farmers. But, according to the Duke research, we're less like the hunter-gather Chimps, than we are the Bonobos. This is strange, given that we're, bar none, the most successful hunter-gathers of all time. If you accept Jared Diamond's arguments, we only became farmers because we were so successful as hunters that we literally exterminated our large-mammal food sources. So how come we don't assess risks like Chimps do? Seems to me that risk assessment is fundamental to the switch from hunter-gatherer to farmer. It revolves around the question, "Do I eat what I can find today, or do I work for a lot of food next month?" That's purely risk assessment, if you ask me.
Chimps almost always choose the potential big pay-off. But that's just another way of saying that some Chimps choose the sure-thing. I suspect the answer to my question is that some humans were also more likely to take the sure-thing. Those humans became farmers. Evolution working how it does, their offspring were more likely to be accepting of the sure-thing than the general population. Eventually, as the number of farmers vastly exceeded the number of hunter-gatherers, accepting the sure-thing became normal.
So why am I writing about this? Well, if you accept this chain of suppositions (and I don't blame you if you don't) then you arrive at the idea that human biology (Sarah Heilbronner's research indicates that there is a biological component to risk assessment) was influenced by a choice. Humans evolved into Bonobo-like sure-thing-acceptors because some of us, the ones from whom we're mostly descended, chose a non-standard risk assessment. That's amazing. It's not self-directed evolution (no human chose to alter human risk assessment, just his own personal strategy for survival). But it is a case of a species' evolutionary path being influenced by the species, rather than a response to the surrounding environment.
Imagine this scenario: Monte Hall gives you $40. Then he tells you you can trade the $40 for a box. There's a 50% chance the box contains $70 (you gain $30). There's a 50% chance the box contains $10 (you lose $30). Risk is calculated as (probability of an outcome) x (value of the outcome). So, whatcha got he-yeh is:
1 x $40 vs [(.5 x $70) + (.5 x $10)]
$40 vs [$35 + $5]
$40 vs $40
in other words, the risk is equivalent. You can't make a rational choice between them.
So, this Duke researcher, Sarah Heilbronner, rounded-up some Chimpanzees and some Bonobos. Genetically, evolutionarily, taxonomically, whatever you call it, these are our closest relatives. She put her test-subjects into the scenario described above (1, 4, and 7 grapes, instead of 1, 4, and 7 10-dollar bills -- both species love grapes). She found that Bonobos choose the guaranteed 4 grapes, almost always (3 of 4 times). Chimps are almost as predictable, but in the opposite direction. Chimps prefer the gamble and big pay-off, Bonobos prefer the certain but lesser pay-off.
Of course, people try to understand from whence arises this difference. The best-received idea involves how each species obtains food. Bonobos have a very reliable food source. The fruit trees from which they eat occur regularly, both in space and time. Chimpanzees don't have that stability. For example, Chimps are hunters. Hunting, unless you have a shotgun, a bait-pile, and a deer population that isn't accustomed to predation, is a big risk. Chimps hunt Colobus monkeys in large packs. That means, if the pack doesn't find a monkey to kill, they all go hungry. They might go a long time without finding a monkey in a situation that allows them to kill & eat it. The thinking is that Chimps have a go-for-broke attitude. Having found a potential big meal, they'll go for it because their biology makes them suspect the small meal might not be enough to get them to the next meal. Bonobos' biology makes them think it's not worth risking a small meal to get a really big one -- after all, there'll be another decent-size meal along tomorrow.
Humans make the same choice as Bonobos, in almost exactly the same proportions -- almost 3/4 times. This is interesting. But, really, what it made me think about is Jared Diamond's work. (Guns, Germs, and Steel and Collapse).
One of his ideas is that humans didn't switch from hunting-and-gathering to farming because it was (as we tend to think) on obviously brilliant strategy for our species' survival. In fact, hunter-gatherers spent less effort acquiring food, ate a more diverse diet, and starved far less frequently than early farmers. But, according to the Duke research, we're less like the hunter-gather Chimps, than we are the Bonobos. This is strange, given that we're, bar none, the most successful hunter-gathers of all time. If you accept Jared Diamond's arguments, we only became farmers because we were so successful as hunters that we literally exterminated our large-mammal food sources. So how come we don't assess risks like Chimps do? Seems to me that risk assessment is fundamental to the switch from hunter-gatherer to farmer. It revolves around the question, "Do I eat what I can find today, or do I work for a lot of food next month?" That's purely risk assessment, if you ask me.
Chimps almost always choose the potential big pay-off. But that's just another way of saying that some Chimps choose the sure-thing. I suspect the answer to my question is that some humans were also more likely to take the sure-thing. Those humans became farmers. Evolution working how it does, their offspring were more likely to be accepting of the sure-thing than the general population. Eventually, as the number of farmers vastly exceeded the number of hunter-gatherers, accepting the sure-thing became normal.
So why am I writing about this? Well, if you accept this chain of suppositions (and I don't blame you if you don't) then you arrive at the idea that human biology (Sarah Heilbronner's research indicates that there is a biological component to risk assessment) was influenced by a choice. Humans evolved into Bonobo-like sure-thing-acceptors because some of us, the ones from whom we're mostly descended, chose a non-standard risk assessment. That's amazing. It's not self-directed evolution (no human chose to alter human risk assessment, just his own personal strategy for survival). But it is a case of a species' evolutionary path being influenced by the species, rather than a response to the surrounding environment.
