Memory trace strength and response biasing in short-term motor memory

Two experiments, which attempted to create differential memory trace strengths in a response biasing paradigm, were performed. After the presentation of the criterion location, an interpolated target was presented which was either ±40 deg from the criterion. The S's task was to attend to both targets and recall each when instructed. The first experiment involved strengthening the criterion trace via repetition (0, 5, or 14 rep.) while the second involved providing additional feedback via visual, auditory, and heightened kinesthetic cues. In the initial experiment, a Repetition by Response Biasing interaction revealed that repetition systematically reduced error shifts at recall. The second experiment found that, in the combined feedback and visual conditions, response biasing was reduced. It seems feasible to suggest that both studies successfully manipulated memory trace strength which appears to be one determiner of error shifts at recall.