Decision Fatigue

The 2011 Israeli parole study reported sharp session-order effects, but later analysis showed the case ordering was not random and identified confounds including legal representation and prison scheduling. The ego-depletion mechanism has also largely failed to replicate, so neither the field study nor the lab account is clean evidence.

In practice

• A recruiter reviewing forty CVs picks more conventionally at 5pm than at 10am, and would deny it.
• A shopper who has compared eleven washing machines buys the one the salesperson recommends, having stopped deciding an hour ago.

Possible explanations

One explanation is depletion, in which the capacity for deliberate control runs down with use. Another is motivation, since people become less willing rather than less able. A third is scheduling, where what looks like fatigue tracks breaks, case order and workload.

In its favour

Defaults do dominate decisions made late in long sequences, and the pattern has been reported in several field settings.

Against it

Ego depletion, the mechanism behind it, has largely failed to replicate, and the parole study most often cited has been challenged for non-random case ordering and confounds.

Standing

Ego depletion has largely failed to replicate, and the parole field study has been challenged on non-random case ordering and confounds.

Further reading

Wikipedia

Subject

Decision-making & Reasoning

Essay

The catalogue of predictable errors