Is timing everything? Age-related differences in the use of temporal agency cues.

Sense of agency (SoA) is the subjective experience of controlling one's own actions and their effects. To infer SoA people rely, among other cues, on temporal cues such as temporal contiguity (i.e. the closeness in time between action and effect) and temporal expectation (i.e. the match between expected and actual timing of an effect). We investigated whether the use of temporal cues and their interplay differ between younger (18-28 years) and older (65-75 years) adults. In the experiment, participants first completed adaptation blocks to form expectations regarding the timing of an effect. In adaptation blocks, actions were followed either by immediate (immediate effect condition) or by delayed (delayed effect condition) effects. In subsequent test blocks, the action-effect delay was varied, and participants SoA over the effect was assessed. Across both age groups, SoA increased, the more the timing of the actual effect corresponded to the expected effect, indicating that temporal expectation is used as primary agency cue. However, in younger (but not in older) adults, the change in SoA as a function of delay was steeper in the immediate effect condition than in the delayed effect condition. This may indicate that temporal contiguity and temporal expectation have reinforced each other in the immediate effect condition but counteracted each other in the delayed effect condition. Thus, whereas both age groups primarily rely on temporal expectation, younger adults may additionally integrate temporal contiguity when inferring SoA.