Drawing attention to previous studies can reduce confidence in a new research finding, even when confidence should increase.

People often learn of new scientific findings from brief news reports, and may discount or ignore prior research, potentially contributing to misunderstanding of findings. In this preregistered study, we investigated how people interpret a brief news report on a new drug for weight loss. Participants read an article that either highlighted the importance of prior research when judging the drug's effectiveness, or made no mention of this issue. For articles describing no prior research, mean confidence in the drug was 62%. For articles that noted prior research was conducted, confidence increased as the proportion of studies with positive findings increased. When prior research was highlighted, confidence decreased by a small amount, even when it should have increased (i.e., even when most of the evidence supported the drug's effectiveness). Thus, people's judgements were more sceptical, but not necessarily more accurate. Judgements were not affected by education level, statistics experience, or personal relevance of the research topic.

Acceptance of anomalous research findings: explaining treatment implausibility reduces belief in far-fetched results.

Research findings are best understood by considering contextual factors such as treatment plausibility: how likely it is that a studied treatment or manipulation is effective, based on theory and data. If a treatment is implausible, then more evidence should be required before believing it has an effect. The current study assessed the extent to which the interpretation of a research finding is affected by treatment plausibility. Participant age varied from 18 to 82 (M = 27.4, SD = 9.4), and about half of the participants (53%) were college students. A total of 600 participants read a brief news article about an experiment with a new type of psychotherapy for weight loss. The current study used a 2 (treatment plausibility) × 3 (results type) between-subjects factorial design. Treatment plausibility had two levels: (1) a plausible cognitive behavioral therapy and (2) an implausible "psychic reinforcement therapy" that was described as employing psychic messages to promote weight loss. The three levels of the results type factor varied how the study results were presented in the article: (1) standard results with no mention of treatment plausibility, (2) standard results followed by interpretive statements focused on treatment plausibility, and (3) no results-the study was described as still in progress. Participants rated their belief in the effectiveness of the therapy on a scale of 0 to 100% in 10% increments. When treatment plausibility was not discussed in the article, average ratings for the implausible therapy were relatively high (M = 63.1%, SD = 25.0, 95% CI% [58.2-68.1]) and similar to those for the plausible therapy (M = 69.2%, SD = 21.5, 95% CI% [65.0-73.5]). Ratings for the implausible treatment were moderately lower when the article explained why the results supporting it were questionable (M = 48.5%, SD = 26.6, 95% CI% [43.2-53.8]). The findings of the current study suggest that students and other members of the public may draw incorrect inferences from research partly because they do not appreciate the importance of treatment plausibility. This could be remedied, though not completely, by explicitly discussing the plausibility of the treatment based on theory and prior data.

Biased lineup instructions and face identification from video images.

Previous eyewitness memory research has shown that biased lineup instructions reduce identification accuracy, primarily by increasing false-positive identifications in target-absent lineups. Because some attempts at identification do not rely on a witness's memory of the perpetrator but instead involve matching photos to images on surveillance video, the authors investigated the effects of biased instructions on identification accuracy in a matching task. In Experiment 1, biased instructions did not affect the overall accuracy of participants who used video images as an identification aid, but nearly all correct decisions occurred with target-present photo spreads. Both biased and unbiased instructions resulted in high false-positive rates. In Experiment 2, which focused on video-photo matching accuracy with target-absent photo spreads, unbiased instructions led to more correct responses (i.e., fewer false positives). These findings suggest that investigators should not relax precautions against biased instructions when people attempt to match photos to an unfamiliar person recorded on video.

Perceived Honesty and Face Memory.

This research examined how perceived honesty affects face memory. Photographs of college men and women were rated for honesty, and then selected exemplars of honest and dishonest faces were shown singly for study as targets. In the test phase, four types of four-face arrays were shown: (a) honest targets with honest distracters, (b) dishonest targets with honest distracters, (c) honest targets with dishonest distracters, and (c) dishonest targets with dishonest distracters. In addition, half of the four-face arrays involved four new faces (target absent). The primary effect of honesty in the target-present arrays was on confidence judgments, with subjects being more confident of their decisions about dishonest targets. In the target-absent arrays, there were more false alarms when honest-looking alternatives were present, contrary to what would be expected if a criminal stereotype was operating. A second experiment using only target-present arrays found better recognition and greater confidence associated with dishonest faces. An examination of additional ratings on this set of faces for typicality, attractiveness, and likability, revealed that overlapping features may be more responsible for these effects than the operation of a criminal stereotype.