What many today consider to be the “irrationalities” of adult human cognition may not be so unique to man, posited Yale professor Laurie Santos last Friday at a colloquium sponsored by the Department of Psychology and Brain Sciences.
Finding the “cognitive origin” has long been a quest of many scientists. It was once thought that this origin lay somewhere in the early stages of human life. Recently, it has been shown that babies in fact exhibit basic causal, numerical, and object knowledge – “babies are very smart,” said Santos.
Moreover, while humans are assumed to grow ‘smarter’ as they develop and gain experience, they nevertheless exhibit “very systematic ways of deviating” from what is thought to be rational. “Thus, it may be that these adult human biases transcend factors such as experience and culture, and first arise during early human development – or perhaps even before human evolution altogether,” said Santos.
To explore this hypothesis, Santos and her team conducted a series of experiments that tested whether certain human biases exist in such human ancestors as lemurs, capuchin monkeys, and macaque monkeys.
One experiment tested for the cognitive bias known as anchoring – a bias by which humans become fixed upon and make subsequent decisions based on an initial number that they are presented with. Santos and her team performed a study with macaque monkeys in which they tested the monkeys’ estimates of the sum of the numbers 1 through 5. Santos and her team found that when the revealed number of strawberries in the box was too high compared with the initial number of strawberries, the monkeys were more likely to stare at the opened box for a longer time.“ What the monkeys deemed as an unexpected result was based upon the first number that they saw – the monkeys, too, exhibit an anchoring bias,” said Santos.
In another experiment, Santos and her team explored whether young children and capuchin monkeys show signs of cognitive dissonance, a phenomenon evidenced among adult humans. Cognitive dissonance occurs when a person’s decisions are capable of molding his preferences. Santos and her team had children rank and choose stickers and the monkeys choose between different colored M&Ms and Skittles. “In both cases, the subjects disproportionately chose against the object that they rejected – results that are consistent with the theory of cognitive dissonance,” explained Santos.
Santos then tested whether capuchins show signs of three phenomena of prospect theory: reference-dependence (judging a situation based upon relative reference points), loss aversion (judging whether to take risks according to the subsequent perceived loss), and the endowment effect (feeling worse when they lose something they own than feeling happy when they gain something new). Prospect theory in general refers to humans’ tendency to “violate tenants of rational choice” in certain situations.
By training capuchin monkeys to use “capuchin fiat currency” (washers) in a market where they could purchase food, Santos and her team performed several experiments in which they observed that the monkeys do in fact behave very similarly to humans when presented with certain trading risks and options and act according to the human prospect theory.
These revealing experiments suggest that human “irrationalities” or biases may be evolutionary, opening a huge “question box”: Are there any biases that are unique to humans? Why do these biases even exist? “Perhaps, they are not irrationalities after all,” said Santos.
Interesting article.