magazine issue 4 2009 / Issue 9

Embodied Persuasion: How the Body Can Change our Mind

• written by Pablo Briñol
• edited by Selin Kesebir

Bodily Responses Influence Thought-Confidence

So far, we have seen how the body can influence attitudes by serving as a simple cue and by affecting either the amount or direction of thinking. Recently, Richard Petty and I have proposed that behavior can not only influence what people think about things, but can also impact what people think about their thoughts (i.e., meta-cognition). This idea is referred to as the self-validation hypothesis (Petty, Briñol & Tormala, 2002). The key notion is that generating thoughts is not sufficient for these thoughts to have an impact on judgments. Rather, one must also have confidence in one’s thoughts. Our self-validation view argues that the confidence that emerges from behavior can magnify the effect of anything that is currently available in people’s minds, including not only their thoughts about a persuasive message, but also other cognitions, emotions, goals, and so forth. That is, confidence applies to whatever mental contents are salient and available at the time (see Briñol & Petty, 2009, for a review).

Consider the research on head nodding described earlier, which had assumed that nodding one’s head in a vertical (versus horizontal) manner produced more positive attitudes either because vertical head nodding biased thinking in a favorable direction or because head nodding served as a relatively simple affective cue. The self-validation hypothesis suggests another possibility. Specifically, this hypothesis suggests that just as vertical head movements from others give us confidence in what we are saying, our own vertical head movements could give us confidence in what we are thinking. In a series of studies, we (Briñol & Petty, 2003) found that head movements affected the confidence people had in their thoughts and thereby had an impact on attitudes. Thus, when people listened through head phones to strong arguments advocating that students be required to carry personal identification cards on campus, vertical movements led to more favorable attitudes than horizontal movements, as would be expected if vertical movements increased confidence in one’s favorable thoughts. However, when people listened to weak arguments in favor of the identification cards, vertical movements led to less favorable attitudes than horizontal movements, as would be expected if vertical movements increased confidence in one’s negative thoughts.

In a different exploration of this possibility (Briñol & Petty, 2003, Experiment 4), we asked participants, as part of a presumed graphology study, to think about and write down their best or worse qualities (i.e., thought-direction manipulation) using their dominant or non-dominant hands (i.e., overt behavior manipulation). Then, participants rated the confidence in the thoughts they listed and reported their self-esteem. Since writing with the non-dominant hand happens infrequently and is very difficult, and because whatever is written with the non-dominant may appear "shaky," we expected and found that using the non-dominant hand decreased the confidence with which people held the thoughts they had listed. As a consequence, the effect of the direction of thoughts (i.e., positive vs. negative) on state self-esteem was significantly greater when participants wrote their thoughts with their dominant hand than with their non-dominant hand. That is, writing positive thoughts about oneself with the dominant hand increased self-esteem relative to writing positive thoughts with the non-dominant hand, but writing negative thoughts with the dominant hand resulted in the reverse pattern. When writing about the things we do not like about ourselves, we feel better if we use the non-dominant (vs. dominant) hand. This is interesting because it reveals that people do not feel too badly about themselves, even though they have just listed negative self-relevant thoughts in objectively unattractive handwriting. More recently, Briñol, Petty, and Wagner (2009) found similar results when participants had to write their qualities while they were sitting with their back erect, pushing their chest out (confident posture) or slouched forward with their back curved (doubt posture). For body actions to influence thought confidence, people have to have thoughts to begin with, and also think about them.