Exploratory Analyses
PPU
In considering the lack of support for the confirmatory hypotheses, it was noted that in terms of past 4-week FPU, the large majority of the sample reported using pornography three times a week or four times a week (61.4%), with fewer reporting five times a week or six times a week (19.3%) and once a day or more than once a day (19.3%). This appeared to be contributed to by the large proportion of female participants (64.2%) in the sample, most of whom reported past 4-week FPU of three times a week or four times a week (77.0%), with fewer reporting five times a week or six times a week (13.3%) and once a day or more than once a day (9.7%). This was in contrast to male participants, who had a roughly equal proportion of participants reporting past 4-week FPU of three times a week or four times a week (32.8%), five times a week or six times a week (31.1%) and once a day or more than once a day (36.1%). Examination of baseline characteristics of the sample by gender showed statistically significant gender differences, most notably male participants having significantly higher PPU (On the basis that abstinence effects might manifest only at higher levels of past 4-week FPU, exploratory MLM analyses were run on each outcome measure to account for potential moderating effects of past 4-week FPU. All variables in the confirmatory MLM models were retained, but with past 4-week FPU now specified as a moderator (i.e., three-way interaction [group × PPU × past 4-week FPU] or two-way interaction [group × past 4-week FPU]; see Tables S11 and S12 in Supplementary Material).In the craving model, there was a significant main effect of group (Effect of group on craving by PPU level (± 1 SD) at all six levels of past 4-week FPUAt low levels of PPU, there were no significant differences between abstinence and control groups on craving at all levels of past 4-week FPU. However, at high levels of PPU, there were differential effects of group on craving depending on level of past 4-week FPU. More specifically, the control group had significantly higher craving than the abstinence group over the experimental period when PPU level was high and past 4-week FPU was “3 times a week” (Finally, at the request of a reviewer, a supplementary set of exploratory MLM analyses was run on each outcome measure to rule out the possibility that abstinence effects manifested only at specific time points (e.g., in the middle or toward the end) of the 7-day period. To achieve this, all variables in the previous exploratory MLM models were retained, but with time now specified as a moderator (i.e., three-way interaction [group × PPU × time] or two-way interaction [group × time]; see Tables S14-S16 in Supplementary Material). In all models, both linear and quadratic time terms were specified, to allow for potential nonlinear trends. MLM results indicated no significant group × PPU × (linear/quadratic) time nor group × (linear/quadratic) time interactions in any of the models, suggesting that there were no significant abstinence effects on any of the outcome variables at a specific time point of the 7-day period. Overall, it is important to emphasize that all exploratory analyses in the present study should be interpreted with caution given the limited statistical power in the present study’s sample to detect three-way interaction effects if any exist.