The positivity effect as a mediator for age-related positive-skew bias: An unsuccessful study

People across the lifespan prefer positively skewed gambles—those with a small chance of winning a large amount coupled with a large chance of losing a small to moderate amount (e.g., a lottery ticket). However, older adults have been seen to show an even stronger bias for these positively-, compared to negatively-, skewed gambles. This age-related increase in positive skew bias may be related to the age-related positivity effect—i.e., an increase in attention to and memory for positive information seen in later life. In this study, we test whether the positivity effect, as assessed by memory for choice features, may explain the increased preference for positively skewed gambles seen in later life. We predicted that the positivity effect would mediate the relationship between age and positive skew preference. However, after collecting data from approximately half of the required participants (N = 117/220), we found that neither the age-related positivity effect nor the age-related positive-skew bias emerged, despite having enough statistical power to detect these relationships. Because age was unrelated to the positive skew bias, there was no statistical relationship to mediate. Thus, to preserve time and resources, we stopped data collection. In this paper, we present explanations for these effects' absence.