Pre-crastination across physical and cognitive tasks.

Pre-crastination refers to the tendency to begin a task as soon as possible, even at the cost of additional effort. This phenomenon is consistently observed in tasks in which participants are asked to select one of two buckets to carry to a target. Surprisingly, on a high proportion of trials participants choose the bucket that is closer to them (and further from the target) as opposed to the bucket that is further from them (and closer to the target).

Properties of context-driven control revealed through the analysis of sequential congruency effects.

The context specific proportion congruent (CSPC) effect refers to the reduction in the size of the congruency effect at locations with a high proportion of incongruent trials compared to locations with a high proportion of congruent trials. The CSPC effect is commonly taken as evidence for context-driven modulation of cognitive control. Current models of context-driven control suggest that variations in the efficiency of control across locations are due to variations in the occurrence of conflict across locations (context).

Limits on the generalizability of context-driven control.

Context-driven control refers to the fast and flexible weighting of stimulus dimensions that may be applied at the onset of a stimulus. Evidence for context-driven control comes from interference tasks in which participants encounter a high proportion of incongruent trials at one location and a high proportion of congruent trials at another location. Since the size of the congruency effect varies as a function of location, this suggests that stimulus dimensions are weighted differently based on the context in which they appear.

When and why do old adults outsource control to the environment?

Old adults' tendency to rely on information present in the environment rather than internal representations has been frequently noted, but is not well understood. The fade-out paradigm provides a useful model situation to study this internal-to-external shift across the life span: Subjects need to transition from an initial, cued task-switching phase to a fade-out phase where only 1 task remains relevant. Old adults exhibit large response-time "fade-out costs," mainly because they continue to consult the task cues.

Contextual influences on the sequential congruency effect.

The sequential congruency effect (SCE) refers to the reduction in the size of the congruency effect following incongruent, relative to congruent, trials. Prior evidence indicated that the SCE does not generalize across tasks or different conflict-producing feature dimensions. We present results from a Stroop task showing that when the local list context is such that all colors and words appear in the same proportion of congruent trials, the SCE is present, but when those same items vary in the proportions congruent, the SCE is absent.