Precise Answers to Vague Questions: Issues With Interactions

Abstract

Psychological theories often invoke interactions but remain vague regarding the details. As a consequence, researchers may not know how to properly test them, and potentially run analyses that reliably return the wrong answer to their research question. We discuss three major issues regarding the prediction and interpretation of interactions. First, interactions can be removable in the sense that they appear or disappear depending on scaling decisions, with consequences for a variety of situations (e.g., binary or categorical outcomes, bounded scales with floor- and ceiling-effects). Second, interactions may be conceptualized as changes in slope or changes in correlations, and since these two phenomena do not necessarily coincide, researchers might draw wrong conclusions. Third, interactions may or may not be causally identified, and this determines which interpretations are valid. We illustrate each of these issues with examples from psychology and issue recommendations for how to best address them in a productive manner.

Phasic pupillary responses reveal differential engagement of attentional control in bilingual spoken language processing

“…Critically, these findings would not be apparent had we simply examined differences in pupil responses without considering the joint effect of individual attentional skill and bilinguals’ habits of language use. Taken together, these data highlight the value of examining interactions over main effects 67 and overall provide a compelling case for the need for a rich characterization of the participant sample and their interactional context 11 , 58 coupled with ecologically valid measures of codeswitching 53 , 68 . Although the pattern of results is complex, it provides important insight into the flexibility and efficiency to which bilinguals draw on resources associated with language control as they selectively attend to and extract linguistic information on the fly.…”

Daily stress reactivity: The unique roles of personality and social support

“…To more specifically tackle the question of determinants of perceived benefits of social support, future studies may also consider assessing interactive effects of personality and social support on momentary stress processes. Because interaction effects require large sample sizes (e.g., Rohrer & Arslan, 2020) and thoughtful consideration of the strength and form of the effects, we suggest basing related analyses on carefully planned and (ideally) preregistered study protocols, thus reducing potential threats to reliability and preventing the introduction of false‐positives into the literature.…”

Daily Stress Reactivity: The Unique Roles of Personality and Social Support

“…To more specifically tackle the question of determinants of perceived benefits of social support, future studies may also consider assessing interactive effects of personality and social support on momentary stress processes. Because interaction effects require large sample sizes (e.g., Rohrer & Arslan, 2020) and thoughtful consideration of the strength and form of the effects, we suggest basing related analyses on carefully planned and (ideally) preregistered study protocols, thus reducing potential threats to reliability and preventing the introduction of falsepositives into the literature.…”