Gain-loss effect refers to the finding that we like people the most if we feel we have gained in their estimation of us (i.e., if they initially disliked us but now like us) and that we dislike people the most if we feel we have lost their favor (i.e., if they initially liked us but now dislike us).
The gain-loss effect is a psychological phenomenon that refers to the tendency for people to be more influenced by changes in evaluation or status than by the evaluation or status itself. Specifically, people tend to feel more positive about a person or thing when there has been a gain in evaluation or status than when there has been no change or a loss.
One classic example of the gain-loss effect is a study conducted by Aronson and Linder in 1965. In this study, male participants were asked to rate the attractiveness of a female confederate. The participants were randomly assigned to one of three conditions: a constant condition, in which the confederate's attractiveness was consistently rated as average; a gain condition, in which the confederate's attractiveness was initially rated as below average but improved over time; and a loss condition, in which the confederate's attractiveness was initially rated as above average but declined over time. The results showed that participants in the gain condition rated the confederate as more attractive than those in the constant condition, while participants in the loss condition rated her as less attractive.
Another example of the gain-loss effect can be seen in the context of social comparison. For instance, if someone receives positive feedback from someone who they view as superior or successful, they may feel a greater sense of validation and self-worth than if they receive the same feedback from someone they view as inferior or unsuccessful.
Similar to the gain-loss effect are the contrast effect and the assimilation effect. The contrast effect occurs when a person's evaluation of a stimulus is influenced by the presence of another, contrasting stimulus. For example, if someone sees a very attractive person immediately before seeing a moderately attractive person, the moderately attractive person may appear less attractive in comparison. The assimilation effect, on the other hand, occurs when a person's evaluation of a stimulus is influenced by the similarity of the stimulus to other stimuli they have recently encountered. For example, if someone sees a series of moderately attractive people before seeing a very attractive person, the very attractive person may appear even more attractive by comparison.
In summary, the gain-loss effect is a psychological phenomenon where people tend to be more influenced by changes in evaluation or status than by the evaluation or status itself. This effect can be observed in a variety of contexts, from interpersonal relationships to social comparison. Similar concepts include the contrast effect and the assimilation effect, which also explore the ways in which evaluations of stimuli can be influenced by surrounding stimuli. Understanding these concepts can help us better understand how people form impressions and make judgments about the world around them.