Event-Based Conformity Versus Regression to the Mean: A Comment on Kim and Hommel (2015)

Abstract

Kim and Hommel (2015) provided an intriguing alternative explanation for conformity effects. Building on the theory of event coding (TEC;Hommel, 2009;Hommel, Müsseler, Aschersleben, & Prinz, 2001), they assumed that one's own and others' actions are represented in comparable ways, so that people may fail to distinguish between those two action categories. As a consequence, "people's actions that have no social meaning should induce conformity effects" (p. 484).Building on a paradigm previously used to investigate social conformity (Klucharev, Hytönen, Rijpkema, Smidts, & Fernández, 2009;Shestakova et al., 2013), Kim and Hommel tested their hypothesis in three experiments involving facial-beauty ratings. In a first block, participants rated the beauty of 220 faces on a scale from 1 to 8 using a computer keyboard. After each rating, participants were presented with an intervening event. Participants saw either a static slide showing a number between 1 and 8 or a short movie in which another person pressed the respective number key (1-8) on a computer keyboard. These numbers were equal to, 2 to 3 points lower than, or 2 to 3 points higher than the rating given by the participant (equal, lower, and higher conditions, respectively). In a second block, all faces were again rated on the same scale from 1 to 8. The hypothesis was that numbers lower than the initial rating should lead to a negativity shift, whereas numbers higher than the initial rating should lead to a positivity shift. The authors present support for this across all three experiments.Critically, the paradigm confounded extremity of initial ratings and assignment of experimental condition (equal vs. lower vs. higher). Since the rating scale was restricted from 1 to 8, experimental condition could not be assigned independently of initial ratings. For example, it was not possible to assign an initial rating of 7 719082P SSXXX10.

Social Cognition 2.0: Toward Mechanistic Theorizing

“…We hasten to add that this observation must not be taken as unequivocal evidence for the validity of our theoretical background. As argued by Ihmels and Ache (2018) and partly confirmed by Kim and Hommel (2018), the paradigm used by Kim and Hommel (2015) and previous researchers is sensitive to regression-to-the-mean effects, which implies that the effect that Kim and Hommel (2015) were able to extend to non-social conditions was actually not a real conformity effect. What we do want to emphasize, however, is that we consider our approach the first truly mechanistic account of conformity behavior which allows for much more specific predictions than the previously suggested descriptive accounts.…”

Medical education and distrust modulate the response of insular-cingulate network and ventral striatum in pain diagnosis

“…This conjecture draws from a recent study employing a similar paradigm, in which participants' reappraisal was also influenced by feedbacks with no social meaning (Kim and Hommel, 2015, but see Klucharev et al, 2009). Third, scholars suggested a potential confound of the initial rating, which depends on the position of the feedback (Ihmels and Ache, 2018;Kim and Hommel, 2018). Indeed, trials with large deviance in one direction are by definition those in which the initial rating is sufficiently distant from the physical boundary of the scale to allow the presentation of the feedback (see methods).…”

An fMRI study on the neural correlates of social conformity to a sexual minority

“…It has been argued that results from studies on conformity may be undermined by the phenomenon known as regression to the mean (RTM) 34,45 , that occurs when an extreme measurement at time 1 is more likely to be followed by a less extreme value at time 2. This makes a natural variation in repeated measures to look like an experimentally-induced change 46 .…”

“…Furthermore, we found that the reliability of the ratings within the female group was fair, whereas the reliability of the ratings within the male group was poor, a result that further justifies our prior selection of the stimuli. It is also important to emphasize that this selection procedure was aimed at alleviating floor effects on the ratings that could have biased the results because of the RTM phenomenon 34,35,45,46 .…”