When we see one good point in a person, we often think the person is good in other ways, too. This is called the halo effect.

For example, people often think that good-looking people are kind and smart. In a 1972 study, students looked at photos of strangers. They thought the attractive people had better personalities and better futures. But a later review of many studies found that looks changed ideas about honesty very little.

The halo effect is our tendency to let one good quality shape our whole judgment of a person. The psychologist Edward Thorndike named it in 1920 after noticing that army officers gave soldiers similar scores for very different traits, such as physique and intelligence.

Later, a 1972 study found that people judged attractive strangers as having nicer personalities and better futures. In a small 1974 experiment, essays received higher grades when they came with a photo of an attractive writer. What makes the halo effect powerful is that people often do not notice it. However, a review of many studies showed that good looks strongly affect judgments of sociability but have only a small effect on judgments of honesty.

The halo effect describes how a single salient positive trait can color our evaluation of a person's other, unrelated qualities. Edward Thorndike introduced the term in 1920 after finding that officers' ratings of soldiers' physique, intelligence and character were suspiciously highly correlated. In 1972, a study titled "What is beautiful is good" reported that attractive faces were associated with better personalities and brighter prospects, and a 1974 experiment suggested that essays were graded more favorably when paired with a photo of an attractive author, particularly when the essay was weak.

A 1977 study went further and showed that students who watched a lecturer behave warmly rated even his appearance and accent as appealing, yet denied that his manner had influenced them. The evidence, however, deserves careful reading. The essay study was a single, small experiment involving a few dozen male students, and the 1977 study had a modest sample too. A 1991 meta-analysis concluded that attractiveness strongly affects perceived social competence but has little effect on judgments of integrity or concern for others. The halo illuminates some traits far more than others.