Communication Currents

To Adam Richards of Texas Christian University, it seemed natural to study the synthesis between the source characteristics that are known to affect persuasion and the characteristics that appear to be related to evolutionary success. A source’s similarity to message recipients has been shown to have a strong effect on a persuasive message’s influence.

Richards and his colleague Dale Hample of the University of Maryland used an evolutionary explanation to support their hypothesis that the persuasive effects of a source’s communicated bias (i.e., self-interest) would disappear when the source’s physical characteristics were similar to those of the message recipients. In other words, Richards and Hample predicted that people are less persuaded by a selfish source compared to selfless source only when the source lacks similar characteristics. When a source shares facial features with message targets, they are not affected negatively by the source’s self-interest.  Accordingly, Richards says, a biased source’s selfishness evokes empathy in people who are primed to think that the source of the persuasive message is genetically related to them. These message recipients believe that if the source benefits, they benefit as well.

The Study 

To test their hypothesis, the authors crafted an experiment that examined the facial similarity of a source to the source’s target (self-morph/other-morph) and the bias of the source (bias/unbias). Ninety-four students from a large Mid-Atlantic university volunteered to be part of the study. Participants were between 19 and 26 years old, and self-reported their race as white (68 percent), African-American (16 percent), Asian (9 percent), or other (7 percent).

To begin, the researchers told students that their participation would allegedly include involvement in two unrelated studies. The first would require participants to have their photo taken. Participants provided their email addresses so they could receive the second study at a later date. Using Psychomorph software, participant photos were then morphed with another face selected from the Karolinska Directed Emotional Faces image set.

Several weeks later, participants received an email with a link to a survey that had them read and answer questions about a student’s public speech that included the speaker’s photograph. The survey was allegedly administered as part of a departmental assessment of student learning in the basic course. Some participants were shown a photograph of the speaker’s face, which had been morphed with an unrecognizable percentage their own face, as the attributed source of the speech. Other participants were shown the morphed face of a different participant. Participants then read a version of a speech about parking policies on campus that was either biased or unbiased, which was manipulated in several ways as well. After viewing the “speaker’s” photograph and reading the speech, participants answered questions about their attitudes toward on-campus parking and their perceptions of the source.

Findings 

The researchers found support for their evolutionary explanation regarding persuasion and facial similarities. Persuasive sources lacking similarity cues elicited less favorable appraisals and attitudes from the message recipients when the sources emphasized their own well-being over that of the message targets. However, message sources that possessed kinship cues elicited no differences in the attitudes or the message appraisals, even when they emphasized their own well-being over that of the targets. In addition, the interaction between facial similarity and the source’s bias had significant direct effects on the target’s attitude toward the source after controlling for competing explanations.

Interestingly, even when participants could not detect the manipulation of facial similarities between themselves and the source’s photo that accompanied the persuasive message, the similarity still affected their attitudes. “This finding suggests that the psychological effect of kinship cues is deep-seated and can operate below one’s level of consciousness,” the authors write.

In their analysis, the authors found an interaction between similarity and bias that supported the concept of nepotistic altruism (the tendency to disadvantage oneself in order to benefit genetically related others). They also found that facial similarity affected positive attributions from the target toward the source, which is in line with other evolutionary communication research showing that familial relation increases prosocial feelings toward another. For example, different types of siblings engage in more positive relational maintenance behaviors as their genetic relatedness increases.

Implications 

An evolutionary explanation for social influence has implications for those who study this phenomenon in the fields of Communication, Marketing, and Psychology. This research provides evidence that perceptions of credibility and attitudinal responses to (dis)similar sources are at least in part intrinsic to message recipients.