Have you ever wondered why the first 60° F (16° C) day after a bitterly cold winter seems quite warm, but the first 60° F day after an intensely hot summer seems rather cool? Clearly, how we judge something depends upon what we are comparing it to. Our evaluations of social objects are also affected by our comparison points, and the theme of this chapter is that all evaluative judgments (including belief and attitude judgments) are relative. In other words, how positive or negative something feels or how it is rated on some attitude scale depends upon what our frame of reference is. For example, when college men were asked to judge the physical attractiveness of a potential date, the date was rated as significantly less attractive if the men had just finished watching a television program starring three very attractive women ("Charlie's Angels") than if they had watched a control program ( Kenrick & Gutierres, 1980). 1 All of the approaches to attitudes and persuasion that we will consider in this chapter share the same view: the psychophysical principles of human judgment that are used to explain why one light is rated as brighter than another, and why one line is rated as longer than another, can be used to understand why one person is more influenced than another, why one message is more persuasive than another, and why one object is rated more favorably than another.
The underlying postulate of judgmental theories, including adaptation level theory as elaborated by Helson ( 1959; 1964), is that all stimuli can be arranged in some meaningful order. Thus, weights can be arranged from the lightest to the heaviest, and attitudes toward some object or issue can be arranged from the most negative (unfavorable) to the most positive (favorable). The theory gets its name from that point on the dimension of judgment that corresponds to the psychological neutral point, called the adaptation level. For example, if you were to put your hand in a bucket of very cold water, eventually your hand would adapt to the water temperature so that the cold water would feel neutral or normal. Subsequent judgments of how cold or warm another bucket of water felt