Embodied Persuasion: How the Body Can Change our Mind
Aside from using mere associations such as those described above, people can also rely on simple heuristics when forming or changing attitudes. For instance, people can draw direct inferences about their attitudes based on their body states (e.g., if my heart is beating fast, I must like this object; Valins, 1966). Moreover, in the domain of emotions, people induced to gaze into each others’ eyes reported feeling romantically attracted to one another (Kellerman, Lewis, & Laird, 1989), and when induced to slump in their chairs, people feel diminished pride in their task performance (Stepper & Strack, 1993).
Bodily Responses Influence the Amount of Thinking
Our body can also make us think about things to a greater or lesser degree. Our postures, facial expressions, and movements sometimes distract us from what is going on, but at other times those same actions can help us to think about things. That is, bodily responses affect the amount of thinking a person does. For example, because certain actions make people feel pleasant and secure, a person might think less about what is going on when smiling than when frowning, or when nodding than when shaking. The body affects the amount of thinking particularly when the person has not really decided whether think carefully about something (i.e., when deciding whether to think or not to think). In an early demonstration that body posture can affect susceptibility to a persuasive communication by affecting the extent of thinking, Petty, Wells, Heesacker, Brock, and Cacioppo(1983) asked undergraduate students to try new headphones to rate their qualities. Some participants were then told to stand while testing the headphones, whereas others were told to lie down while listening to a persuasive proposal. Consistent with the idea that posture can affect thinking, this study showed that while reclining participants were differentially persuaded by the strong and weak arguments (suggesting that they paid careful attention to the message), standing participants were not.
Important practical implications flow from the possibility that body manipulations can induce persuasion by affecting the amount of thinking the individual engages in. For example, the practice of brainwashing often involves a massive assault on the body, in which the victim is frequently starved, drugged, tortured, and emotionally agitated. In other domains, attempts at persuasion may involve the direct control of a person’s behavior, including alteration in appearance (e.g., clothing, posture, hairstyle), public behaviors (e.g., self-criticism), and escalation of commitment, in which a recruit is asked, over time, to engage in increasingly costly behaviors that are hard to undo (e.g., donating one’s personal possessions to the group, or recruiting new members). The combination of physical deprivation and behavior modification has been argued to reduce a person’s motivation and ability to think, thus rendering that person more susceptible to what would ordinarily have been weak arguments (e.g., faulty logic, incomplete verification, erroneous and stereotypical information; for a review, see, Baron, 2000). These simplistic, weak messages could presumably be easily counter-argued if people were not so physically depleted (e.g., Wheeler, Briñol, & Hermman, 2007).
Bodily Responses Influence the Direction of Thinking
Our bodies can influence persuasion not only by affecting the amount of thinking but also by affecting the direction of that thinking. Obviously, for the body to influence thoughts, people need to be thinking. One extensively explored idea is that bodily responses can shape attitudes by affecting the valence (i.e., positivity or negativity) of the thoughts that come to mind when thinking about an attitude object. For example, in the original research on head movements and persuasion, Wells and Petty(1980) speculated that previous experience had made nodding compatible with “approval” and favorable thinking, whereas head shaking was more compatible with “disapproval” and unfavorable thinking. In line with the Wells and Petty proposal about behavior biasing thinking, Neumann, Förster, and Strack (2000) argued that overt behavior can directly trigger compatible thoughts that facilitate encoding and processing of evaluatively congruent information.