Two-condition within-participant statistical mediation analysis: A path-analytic framework.

Abstract

Researchers interested in testing mediation often use designs where participants are measured on a dependent variable Y and a mediator M in both of 2 different circumstances. The dominant approach to assessing mediation in such a design, proposed by Judd, Kenny, and McClelland (2001), relies on a series of hypothesis tests about components of the mediation model and is not based on an estimate of or formal inference about the indirect effect. In this article we recast Judd et al.'s approach in the path-analytic framework that is now commonly used in between-participant mediation analysis. By so doing, it is apparent how to estimate the indirect effect of a within-participant manipulation on some outcome through a mediator as the product of paths of influence. This path-analytic approach eliminates the need for discrete hypothesis tests about components of the model to support a claim of mediation, as Judd et al.'s method requires, because it relies only on an inference about the product of paths-the indirect effect. We generalize methods of inference for the indirect effect widely used in between-participant designs to this within-participant version of mediation analysis, including bootstrap confidence intervals and Monte Carlo confidence intervals. Using this path-analytic approach, we extend the method to models with multiple mediators operating in parallel and serially and discuss the comparison of indirect effects in these more complex models. We offer macros and code for SPSS, SAS, and Mplus that conduct these analyses. (PsycINFO Database Record

Facial Redness Increases Men’s Perceived Healthiness and Attractiveness

“…We used MEMORE (Montoya & Hayes, 2016) for SPSS to test the effect of facial redness on attractiveness through several parallel mediators. MEMORE tests for the indirect effect of each potential mediator while controlling for the indirect effects of the others.…”

Endorsing help for others that you oppose for yourself: Mind perception alters the perceived effectiveness of paternalism.

“…Including beliefs about mental capacity reduced the effect of condition (self, coded as 1 vs. other, coded as 0) on the selection of paternalistic policies in a 5,000-sample bootstrapped mediation model (using SPSS "Memore" macro; Montoya & Hayes, 2016), from ␤ ϭ Ϫ1.05, p Ͻ .001 to ␤ ϭ Ϫ0.89, p Ͻ .001, but the indirect effect was nonsignificant: Ϫ0.16 (SE ϭ 0.14), 95% CI [Ϫ0.48, 0.08], suggesting mental capacity beliefs did not fully Optional exams: The President will allow all courses to have a choice in administering either a final exam, a final paper, or a final presentation.…”

Attitudes and Preferences for Sex-Appealing Products by Vietnamese Women in Their Ovulation Cycle

“…Thus, running, e.g., the increasingly popular Hayes' [43] process macro on the data here was not possible. However, recent advances in statistics have made available a dedicated macro for mediation tests of within-subjects designs [7]. Running this new macro allowed us to formally test the mediating effect of attitudes, as shown in Figure 1, as predicted in H1b.…”

“…Unfortunately, Montoya and Hayes' [7] current version of the MEMORE macro has implemented the testing of mediation, but algorithms for testing moderation Golden heels ( Figure A2 were still under development at the time this article was written. As an alternative, recommendations by [44] and regressed the difference of the Y variable (i.e., attitudes towards sexy and revealing fashion products) on the moderator (formula [6], p. 119) were followed.…”

“…Second, previous research has relied predominantly on consumers from the US or other Westernized countries, and it remains unclear if the results are valid in different cultural contexts. Third, important mediating effects have been neglected so far, mainly because efficient statistical tools to test for mediation in repeated measurement designs (i.e., within-subject designs) have only recently developed [7]. Forth, there is a need to consider the moderating effects of important psychological and demographic traits on the relationship between women's ovulation and their preference towards revealing and sexy fashion products.…”