Cognitive Heuristics

One rule of thumb that has particularly troublesome effects on attribution is the availability heuristic, a tendency to estimate the odds that an event will occur by how easily instances of it pop to mind. To demonstrate, Tversky and Kahneman asked research participants: Which is more common: words that start with the letter r or words that contain r as the third letter? In actuality, the English lan- guage has many more words with r as the third letter than as the first. Yet most people guessed that more words begin with r. Why? Because it’s easier to bring to mind words in which r appears first. Apparently, our estimates of likelihood are heavily influenced by events that are readily available in memory.

Research shows that the availability heuristic can lead us astray in two ways. First, it gives rise to the false-consensus effect, a tendency for people to overestimate the extent to which others share their opinions, attributes, and behaviors. This bias is pervasive. Regardless of whether people are asked to predict how others feel about military spending, abortion, gun control, Campbell’s soup, certain types of music, favorite celebrities, or norms for appropriate behavior, they exagger- ate the percentage of others who behave similarly or share their views.