The Role of Objective and Introspective Switch Costs in Voluntary Task Choice

Public Significance Statement In everyday life, investing effort is one key determinant of success. Yet human beings tend to avoid effort. We show how invested effort (the voluntary switch rate) in our paradigm depends on the individual ability (the switch costs). We also show that participants have introspection about these costs and provide the first evidence that these subjective costs may also guide effort investment. Human beings are cognitive misers. One facet of this effort avoidance is the reluctance to voluntarily switch tasks when repeating the same task is allowed. Yet participants voluntarily switch despite the resulting costs. This paradox might be resolved if the individual switching ability or sensitivity is considered. Here, we investigated whether the voluntary switch rate (VSR) is governed by the objective or the subjective (introspective) switch costs. Three experiments were conducted utilizing voluntary task switching with forced and free task choices intermixed. In Experiments 1 and 3, objective switch costs were measured on forced tasks, and subjective switch costs were calculated from (introspectively) estimated reaction times in a separate phase. In Experiment 2, objective and subjective costs were measured in the same phase. In Experiments 2 and 3, we additionally manipulated the forced switch rate. Results show that objective and subjective switch costs were lower in blocks with higher forced switch rates. The objective switch costs predicted VSR in Experiments 1 and (partially) 3. The subjective switch costs predicted the VSR only in Experiment 3 (the lower the costs, the higher the VSR). Hence, the present study offers first insight into under which circumstances introspection guides decision-making during voluntary task switching.