Without doubt the validity of scientific theories and their usability for solving societal, economic, ecological, and health-related problems are contingent on the existence of robust and replicable empirical findings. However, a review of the recently published replication literature portrays a rather pessimistic picture of the replicability of even very prominent empirical results, as is evident both from large-scale meta-analytic replication projects and from distinct attempts to replicate selected examples of well-established key findings of personality and social psychology. The present chapter offers a twofold explanation for this undesirable state of affairs. On one hand, the widespread evidence on replication failures reflects to a considerable extent the neglect of logical and methodological standards in replication studies, which sorely ignore such essential issues as manipulation checks, reliability control, regressive shrinkage, and intricacies of multi-causality. On the other hand, however, the community of behavioral scientists must blame themselves for an intrinsic weakness of their corporate identity and their incentive and publication system, namely the tendency to mistake sexy and unexpected findings for original insights and neglect of the assets of cumulative science and theoretical constraints.

This chapter explains why no one is perfectly self-controlled, and why even true champions of discipline will sooner or later give in to temptation. The reason is that people are bound by two hardwired constraints: limited working memory and limited mental energy. (Whether the latter constraint actually exists has recently become a subject of fierce debate, but I argue that the critics are mostly mistaken.) This chapter also explains why the capacity for self-control partly depends on the situation. I discuss five factors that may undermine self-control: negative affect, cognitive load, prior exertion of self-control, acute stress, and insufficient sleep. These are factors that all of us experience on a more or less daily basis, meaning that all of us may suffer bouts of poor self-control. To be sure, when the stakes are high, people have mental reserves they can call upon, thus rising to the occasion, but again, there are limits. In the end, no one is immune to self-control failure.