Optical illusions Attribute substitution explains the persistence of some illusions. For example, when subjects judge the size of two figures in a
perspective picture, their apparent sizes can be distorted by the 3D context, making a convincing optical illusion. The theory states that the three-dimensional size of the figure (which is accessible because it is automatically computed by the visual system) is substituted for its two-dimensional size on the page. Experienced painters and photographers are less susceptible to this illusion, because the two-dimensional size is more accessible to their perception.
Stereotypes Stereotypes can be a source of heuristic attributes. In a face-to-face conversation with a stranger, judging their intelligence is more computationally complex than judging the colour of their skin. So if the subject has a stereotype about the relative
intelligence of whites, blacks, and Asians, that racial attribute might substitute for the more intangible attribute of intelligence. The pre-conscious, intuitive nature of attribute substitution explains how subjects can be influenced by the stereotype while thinking that they have made an honest, unbiased evaluation of the other person's intelligence. Given a difficult, novel problem in these areas, people search for a more familiar, related problem (a "prototypical case") and apply its solution as the solution to the harder problem. According to Sunstein, the opinions of
trusted political or religious
authorities can serve as heuristic attributes when people are asked their own opinions on a matter. Another source of heuristic attributes is
emotion: people's moral opinions on sensitive subjects like
sexuality and
human cloning may be driven by reactions such as
disgust, rather than by reasoned principles. Critics demanded more evidence from Sunstein.
The beautiful-is-familiar effect Monin reports a series of experiments in which subjects, looking at photographs of faces, have to judge whether they have seen those faces before. It is repeatedly found that attractive faces are more likely to be mistakenly labeled as familiar. Monin interprets this result in terms of attribute substitution. The heuristic attribute in this case is a "warm glow"; a positive feeling towards someone that might either be due to their being familiar or being attractive. This interpretation has been criticised, because not all the
variance in the familiarity data is accounted for by attractiveness. ==Evidence==