Dual-task interference across practice: reductions in task 2 slowing
Paper presented at the 4th Annual Meeting of the Cognitive
Science Association for Interdisciplinary Learning, Hood River, Oregon.
When subjects attempt to perform two speeded discrimination tasks in
in rapid succession, performance on the second discrimination is often
strikingly impaired. It has previously been reported that extended
practice yields only a minimal decrease in the amount of Task 2 slowing.
In contrast, we found that Task 2 slowing decreases dramatically for
all six subjects across 40 sessions of practice. In one experiment we
demonstrate that this reduction in interference does not occur when the
tasks use the same response modality. Two additional experiments
investigating transfer demonstrate that dual-task interference remains
small when a new (unpracticed) Task 2 is used, but returns to baseline
when a new Task 1 is used. We conclude that the main cause of the
changes that occur with extended practice is a drastic shortening of
bottleneck stages in Task 1.
Practice Drastically Reduces interference in the Psychological
Refractory Paradigm
Paper presented at the 28th Annual Meeting of the Psychonomic Society,
Pittsburgh.
Six subjects were given 36 sessions of practice in a psychological refractory period (PRP) paradigm. Task 1 required vocal responses, while Task 2 required manual responses. Unlike previous experiments with two manual response tasks, practice dramatically reduced the size of the PRP interference, from an initial 353 msec to only 40 msec. Analysis of factor interactions support a central bottleneck model of Task 2 postponement both early and late in practice.