Satoshi Kanazawa

The Scientific Fundamentalist

All stereotypes are true, except... IV: “You can’t judge a book by its cover”

Can you judge a book by its cover?

Posted May 04, 2008

Both Tom Hanks and Ray Liotta are handsome white Hollywood actors roughly the same age. But I am willing to bet that these two actors have never auditioned for the same part in their careers. (Imagine Ray Liotta sitting on a park bench, uttering the line “My name is Forrest Gump. People call me Forrest Gump.”) Why is this? Why are actors typecast?

Tom Hanks usually plays the good guy in movies, whereas Ray Liotta usually plays the bad guy. This is because Tom Hanks looks like a good guy, whereas Ray Liotta looks like a bad guy. If you show pictures of these two men to people in Papua New Guinea, who have never seen any movies in their lives, let alone movies starring Hanks or Liotta, they can probably tell which is the good guy and which is the bad guy. This suggests that the third stereotype or aphorism about physical appearance “You can’t judge a book by its cover,” meaning that you cannot judge people’s characters by their physical appearance, may be false.

There is some experimental evidence to support this suspicion. When people view pictures of others who have been shown to be either a cooperator or a defector, there is some tendency for people to remember the faces of defectors better than the faces of cooperators, even when they don’t know who is a cooperator and who is a defector. Similarly, people appear to be able to distinguish between honest people and dishonest people simply by looking at their pictures.

If you think about it, this makes perfect evolutionary sense. It is important for our ancestors (and for us as well) to guard against the possibility of deception, because being deceived can only have negative consequences for our survival and reproductive success. As a result, the human brain consists of many evolved psychological mechanisms that protect us from being deceived in our social exchange and interpersonal relationships. The ability to tell potential defectors (bad guys) from potential cooperators (good guys) by their appearance would be tremendously helpful for our ancestors (and us) in guarding against possible fraud.

Of course, the nature of evolutionary arms race is such that defectors and other dishonest people will be selected not to betray their deceptive nature by looking honest and trustworthy, so that people won’t be able to tell that they are bad guys. At any rate, evidence against the third stereotype “You can’t judge a book by its cover” is not yet as convincing as the evidence against the first two stereotypes “Beauty is in the eye of the beholder” and “Beauty is only skin deep.” More research is necessary to make sure that the third stereotype is definitely false.

The only exception, in which we already have solid evidence, is where the judgment involves physical attractiveness. The evidence is overwhelming that people judge beautiful people to possess all kinds of positive attributes, from intelligence, to competence, to good character, to social skills, captured in another aphorism “What is beautiful is good.” And the evidence shows that this perception is largely true. For example, beautiful people are slightly though significantly more intelligent than ugly people. Nobody said life was fair.

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