Non-probative Photos Promote the Truth of Positive Claims

People’s judgments are prone to the influence of feelings, even cognitive feelings such as the ease with which related information comes to mind (Alter & Oppenheimer, 2009; Schwarz & Clore, 2007). In 14 experiments, we¹ found evidence that non-probative photos — ones that relate to what people are evaluating, but that provide no relevant information for their task — produce cognitive feelings that lead people to evaluate claims more positively.  In Part 1, we examined the extent to which photos promote the truth of positive and negative claims. People saw the names of several fictitious wines. Some wine names appeared with a photo that depicted the noun in the name; other wine names appeared without a photo. For each wine people decided whether a positive or a negative claim about it was true. Photos selectively promoted the truth of positive claims, did so most when they could help people comprehend wine names, and swayed people’s judgments about the taste of wines.  In Part 2, we showed that those findings translated to when people judged claims about their own (and other people’s) experiences. People “interacted” with several unfamiliar animals (on a computer). Later, people saw the animal names again, sometimes with a photo of the animal and sometimes alone, and decided whether it was true that they (or other people) had positive or negative experiences with the animals. Photos selectively led people to think positive claims were true, and exerted their strongest effects when they could most help people bring related thoughts and images to mind².  ¹ Although the research in this thesis is my own, I conducted it in a lab and supervised a team comprised of research assistants and honors students. I also received advice and direction from my supervisors. Therefore, I often use the word “we” in this thesis to reflect that fact. As you will also see, I use the word “we” in a different context to refer to what is known (or not known) in the wider scientific community.  ² Portions of this thesis were adapted from:  Cardwell, Newman, Garry, Mantonakis, & Beckett (manuscript under review). Photos that increase feelings of learning promote positive evaluations.  Cardwell, Henkel, & Garry (manuscript in preparation). Non-probative photos lead people to believe positive claims about their recent pasts.  But I have expanded on the introduction, results and discussion.