Affect heuristic

The affect heuristic is a heuristic in which current affect influences decisions. Simply put, it is a 'rule of thumb' instead of a deliberative decision. It is one of the ways in which human beings show bias in making a decision, which may cause them to take action that is contrary to logic or self-interest.

Concept
"Affect", in this context, is simply a feeling—fear, pleasure, humorousness, etc. It is shorter in duration than a mood, occurring rapidly and involuntarily in response to a stimulus. Reading the words "lung cancer" usually generates an affect of dread, while reading the words "mother's love" usually generates an affect of affection and comfort. For the purposes of the psychological heuristic, affect is often judged on a simple diametric scale of "good" or "bad".

The theory of affect heuristic is that a human being's affect can influence their decision-making. The affect heuristic got recent attention when it was used to explain the unexpected negative correlation between benefit and risk perception. Melissa Finucane and others theorised in 2000 that a good feeling towards a situation (i.e. positive affect) would lead to a lower risk perception and a higher benefit perception, even when this is logically not warranted for that situation. This implies that a strong emotional response to a word or other stimulus, might alter a person's judgment. (S)he might make different decisions based on the same set of facts and, might thus make an illogical decision. For example, in a blind taste test, a man might like Mirelli Beer better than Saddle Sweat Beer; however, if he has a strong gender identification, an advertisement touting Saddle Sweat as "a real man's brew" might cause him to prefer Saddle Sweat. Positive affect related to gender pride biases his decision sufficiently to overcome his cognitive judgment.

Another common situation involving affect heuristic is where a strong, emotional first impression can inform a decision, even if subsequent facts weigh cognitively against the decisions. Someone seeing a house from the street might decide to buy it immediately upon seeing it, based on the strength of her emotional response to its eye appeal. This can be true even if subsequent inspection shows that it is inferior to another house that is even more charming from the street, but which she first encountered by entering the back door into a rather shabby kitchen.

The affect heuristic is of influence in nearly every decision-making arena. Perhaps the most chilling is an anecdote told by attorneys: "Child molestation is a crime so heinous that innocence is no defense." A problem is that this kind of implication is hardly acknowledged in the professional practice.

Experimental findings
The study of affect heuristics by psychologists have yielded startling results. First, the phenomenon can be rapid. Winkielman, Zajonc, and Schwarz flashed one of three images in the view of test subjects: a smiling face, a frowning face, or a neutral geometric shape. The subject was then shown a Chinese ideograph and asked how he or she liked it. The test subjects preferred the ideographs they saw after the smiling face, even though the smiling face was shown only for 1/250 of a second, and the subject did not recall seeing it.

The same experiment demonstrated the persistence of initial affect. The testers showed the subjects the same ideographs, but preceded by a different face. The subjects significantly tended to prefer the ideographs based on the first association, even where the second exposure was preceded by a different affective stimulus. That is, if a subject liked an ideograph following exposure to a smiling face, he would continue to like the ideograph even when it was preceded by a frowning face. (The experimental outcome was statistically significant and adjusted for variables such as non-affective preference for certain ideographs.)

However, in spite of its intuitive appeal and a large number of indirect empirical findings supporting the affect heuristic (such as the experiment above), conclusive evidence proving the theoretical ideas posed in the affect heuristic has not been forthcoming as of yet.