Ego depletion, the idea that willpower is a limited resource, faces a crisis deeper than failed replications. The field cannot even agree on what self-control is or how to measure it.
Paper: Challenges to Ego-Depletion Research Go beyond the Replication Crisis
Is willpower like a battery that can run out? The popular theory of ego depletion says yes.
However, a major replication with 23 labs and over 2,000 participants failed to reproduce the effect.
What's worse, researchers Lurquin and Miyake argue that the replication failure is only the surface. There are three more conceptual problems beneath.
First, there is no clear definition of self-control. The same task, such as three-digit multiplication, has been used as a self-control task in some studies and as a non-depleting control in others.
Second, the tasks have never been independently validated as measures of self-control. The assumption that all self-control draws on a single shared resource relies on circular logic.
Last, the models are too vague to test. The "strength model" does not specify how resources are consumed. A recent update made it so flexible that it can explain any result. If a model explains everything, it explains nothing.
Therefore, even larger samples cannot save this field because it has not clearly defined what it studies.
This also reminds me of Augustine's divided will. The experience of conflicting wants is real, but the battery metaphor may not be.