WE ALL tend to rationalise our bad decisions and try to hide our mistakes, even from ourselves. Now it turns out that the psychological machinery to do this exists even in young children, and evolved a surprisingly long way back in our primate ancestry.
When things go wrong for us, we have a choice 鈥� give up on a cherished self-image (鈥淚鈥檓 irresistible to women,鈥� say), or keep it and play down the situation (鈥淚 didn鈥檛 really like her anyway鈥︹��). Over the past 50 years, hundreds of studies have revealed the many tools at our disposal which cope with this 鈥渃ognitive dissonance鈥� 鈥� from selective memory to the biased framing and retelling of events. These allow us to live with our choices and, ultimately, ourselves, yet their origins are poorly understood.
鈥淪elective memory and the biased framing and retelling of events allow us to live with our choices and, ultimately, ourselves鈥�
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To explore the evolutionary and developmental roots of cognitive dissonance, and how we resolve it, Louisa Egan and colleagues at Yale University designed tests to elicit conflicting thoughts in 4-year-old children and in capuchin monkeys. The children were initially asked how much they liked a variety of animal-shaped foam stickers. Each child was then shown three stickers which they had rated as equally desirable. Two of these were available for them to take home, while the third was not, and the child was asked to decide which one of the two to keep. Having made their choice, they were told they could also take either the unchosen sticker of the original pair, or the third sticker.
For the monkeys, stickers were replaced by 20 differently coloured M&M sweets 鈥� each monkey鈥檚 colour preferences having been determined by how quickly they retrieved the sweets from a testing chamber. Like the children, the monkeys were then offered a choice between two M&Ms out of a set of three of the same desirability, followed by another choice between the rejected and previously unoffered sweet.
These tasks generate cognitive dissonance in a subtle way. Ordinarily we choose according to our preferences, but being forced to choose arbitrarily between equally preferred options sets up a conflict with this approach. One way to resolve this dissonance is to update your preferences to accord with the choice you make by devaluing the rejected option, so that in retrospect it seems non-arbitrary. What鈥檚 more, the devalued option should, if the brain is stepping in to resolve internal conflict, subsequently seem less desirable than a previous equal.
This is exactly what Egan鈥檚 group found: both the children and the monkeys appeared to update their preferences. When presented with the second choice, they were more likely to reject what had previously been an equally preferred option in favour of the third sticker or sweet, revealing cognitive dissonance and its resolution in action. In control groups, where the first sticker or sweet was randomly allotted, there was no subsequent revaluing of options.
This, says Egan, is the first evidence for decision rationalisation in children and non-human primates (Psychological Science, vol 18, p 978).
The work challenges the popular notion of cognitive dissonance as a complex process requiring sophisticated self-awareness, says Eddie Harmon-Jones, a psychologist at Texas A&M University, College Station. 鈥淭his beautiful study conclusively demonstrates dissonance processes in 鈥榤inimal鈥� cognitive situations,鈥� he says.
The findings also contribute to a growing emphasis on the similarities between human, ape and monkey minds. 鈥淭hey鈥檙e part of a growing body of research demonstrating fundamental commonalities in the way human and non-human primates process, and even interpret and evaluate information from their physical and social worlds,鈥� says Michael Tomasello, an expert on primate cognition at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Egan and colleagues now intend to take their approach into more challenging domains. 鈥淲e鈥檙e planning to explore the development of moral hypocrisy and the rationalisation of moral behaviour in children and primates,鈥� she says.
The Human Brain 鈥� With one hundred billion nerve cells, the complexity is mind-boggling. Learn more in our cutting edge special report.
