Self-control may not be limited resource after all

Whether it is walking past your favourite store or refusing that second slice of pizza, everything seems to boil down to one essential bit

The research replication project, involving 24 labs and over 2100 participants, failed to reproduce findings from a previous study that suggested that self-control is a depletable resource.

Over the last twenty years, numerous studies have provided evidence supporting the idea that our capacity for self-control is finite - using self-control on one task reduces an individual's ability to exert self-control on a subsequent task. But recent analyses have challenged the strength of this so-called ego depletion effect.

Gaining a clearer understanding of the ego depletion effect is important given that our ability to override impulses is critical to everyday functioning and has been implicated in long-term outcomes related to health, achievement, and well-being.

To investigate the strength of the ego depletion effect, psychological scientists Martin S. Hagger and Nikos L. D. Chatzisarantis of Curtin University in Australia proposed a Registered Replication Report (RRR), in which researchers from multiple labs use the same methods and procedure to conduct independent replications of an experiment.

The particular study used for the RRR was from a 2014 article published in Psychological Science by Chandra Sripada, Daniel Kessler and John Jonides. Computerized tasks were performed in succession to test the ego depletion effect, which meant that the procedure could be standardized and implemented across multiple labs. Hagger and Chatzisarantis developed the protocol for the RRR in close consultation with Sripada and Kessler, using the tasks and procedure from the original study.

A total of 24 labs - from countries including Australia, Belgium, Canada, Indonesia, Sweden, and the United States - completed independent replications with a combined total of 2141 participants. Each lab's implementation plan was vetted by Alex O. Holcombe (University of Sydney), editor of the RRR, to ensure consistency with the protocol.

"Do the current results suggest that the ego-depletion effect does not exist after all? Certainly the current evidence does raise considerable doubts given the close correspondence of the protocol to the standard sequential-task paradigm typically used in the literature, and the tightly-controlled tasks and protocol across multiple laboratories," Hagger and Chatzisarantis wrote in their report.

Sripada, Kessler, and Jonides acknowledged that the RRR does not replicate their earlier findings, but urge caution in interpreting the results too broadly. They note that tasks used to measure ego depletion vary considerably across studies and may depend on somewhat different underlying mechanisms.

"Caution is thus required in drawing implications from the results of this RRR for the phenomenon of ego depletion writ large," they wrote in a commentary accompanying the RRR.

The findings are published in journal Perspectives on Psychological Science.