A nuanced view of the extent to which samples from narrow populations are scientifically problematic.

Psychologists have a traditional concern with participant samples from narrow populations and deleterious effects on researchers' ability to generalize findings. Recently, both individuals and authoritative organizations, such as the American Psychological Association, have merged this external validity concern with diversity and inclusion concerns. The American Psychological Association directive for researchers to include diverse samples seems obviously well-taken as it purports to mitigate these problems at once; it simultaneously increases external validity and promotes diversity and inclusion. However, we show that there are complications. These include problems with internal and external validity conceptualizations; that sometimes generalization failures can support, rather than detract from, external validity; the crucial role auxiliary assumptions play in impacting internal and external validity; Lakatosian degenerative science and its problematic application; and distinguishing between merely including diverse groups in research samples versus analyzing for group differences. These complications imply a nuanced perspective of whether samples from narrow populations are undesirable. That a sample is from a narrow population might, or might not, preclude strong support or disconfirmation for the theory, including its ability to generalize. Our nuanced perspective militates against the current trend of journal directives to require diverse samples. Sample suitability for particular researcher goals should be judged on a case-by-case basis that takes into account that sometimes samples from narrow populations can nevertheless engender impressive scientific progress and sometimes not. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

No evidence of attentional prioritization for threatening targets in visual search.

Throughout human evolutionary history, snakes have been associated with danger and threat. Research has shown that snakes are prioritized by our attentional system, despite many of us rarely encountering them in our daily lives. We conducted two high-powered, pre-registered experiments (total N = 224) manipulating target prevalence to understand this heightened prioritization of threatening targets. Target prevalence refers to the proportion of trials wherein a target is presented; reductions in prevalence consistently reduce the likelihood that targets will be found. We reasoned that snake targets in visual search should experience weaker effects of low target prevalence compared to non-threatening targets (rabbits) because they should be prioritized by searchers despite appearing rarely. In both experiments, we found evidence of classic prevalence effects but (contrasting prior work) we also found that search for threatening targets was slower and less accurate than for nonthreatening targets. This surprising result is possibly due to methodological issues common in prior studies, including comparatively smaller sample sizes, fewer trials, and a tendency to exclusively examine conditions of relatively high prevalence. Our findings call into question accounts of threat prioritization and suggest that prior attention findings may be constrained to a narrow range of circumstances.

Can the processing of task-irrelevant threatening stimuli be inhibited? - The role of shape and valence in the saliency of threatening objects.

Numerous studies have demonstrated that attention is quickly oriented towards threatening stimuli, and that this attentional bias is difficult to inhibit. The root cause(s) of this bias may be attributable to the affective (e.g., valence) or visual features (e.g., shape) of threats. In two experiments (behavioral, eye-tracking), we tested which features play a bigger role in the salience of threats. In both experiments, participants looked for a neutral target (butterfly, lock) among other neutral objects. In half of the trials a threatening (snake, gun) or nonthreatening (but visually similar; worm, hairdryer) task-irrelevant distractor was also present at a near or far distance from the target. Behavioral results indicate that both distractor types interfered with task performance. Rejecting nonthreatening distractors as nontargets was easier when they were presented further from the target but distance had no effect when the distractor was threatening. Eye-tracking results showed that participants fixated less often (and for less time) on threatening compared to nonthreatening distractors. They also viewed targets for less time when a threatening distractor was present (compared to nonthreatening). Results suggest that visual features of threats are easier to suppress than affective features, and the latter may have a stronger role in eliciting attentional biases.