Personality Change Through Self-Improvement or Self-Acceptance: A Multi-Study Approach Accounting for Expectancy and Demand Effects

Volitional personality change interventions have been shown to help people change their current personality towards their ideal personality. Here, we address three limitations of this literature. First, we contrast the dominant theoretical perspective of self-improvement with self-acceptance as pathways to reduce the discrepancy between current and ideal personality. Second, we test how well-being aspects change as a by-product of targeting personality. Third, we use a waitlist control group to account for expectancy and demand effects. Across three studies (combined N = 2,094; 1,044 women, 1,050 men; M_age = 30.78, SD_age = 9.70, range_age = 18-105), we implemented randomized online interventions of self-improvement or self-acceptance over a 3-month period, with another follow-up 6 months after baseline and a waitlist control group added in Study 2. Across Studies 1 and 2, participants in both intervention groups reduced discrepancies between current and ideal personality and increased in well-being. In both intervention groups, current personality ratings increased, whereas ideal personality remained stable. Critically, however, control group participants changed in the same fashion, with similar or only slightly smaller effect sizes than participants who received an intervention. Study 3 compared different control group specifications and demonstrated that demand effects elicited by the framing as an intervention explained positive changes in neuroticism, conscientiousness, and extraversion as well as life satisfaction and self-esteem. Thus, the current studies highlight both shortcomings of previous intervention designs and imprecisions in theoretical frameworks of personality change mechanisms. We discuss future directions including multi-method studies, measurement advances, and micro-randomization of intervention components.