Performance of Series of Movements Specified by a Sequence of Sensory Signals. Individual Differences at the Initial State of Sequence Learning

Abstract

Individual characteristics of the initial stage of sequence learning were studied in a task consisting of reproducing a sequence of movements specified by a sequence of visual stimuli. A total of 20 adult subjects took part in the study; along with the sequence reproduction task, the subjects performed a simple visuomotor reaction, a selection task, and a serial choice response task. Individual relationships between the latent period of performing the sequence and the trial number, i.e., the learning curve, had a characteristic feature: decreases in latent periods, if observed, occurred either rapidly during the first 10 trials to reach a stationary level (the rapid phase) or decreased slowly and essentially linearly throughout the entire block of 60 trials (the slow phase). Individual learning curves were of four types: flat relationships, curves with a rapid phase, curves with a slow phase, and curves in which a rapid phase was followed by a slow phase. The learning curves of all the subjects were thus divided into four groups. Correlation structures of the time parameters (latent periods and durations of intervals between movements) were studied within groups and in terms of the ratios of these parameters with the times taken to perform simple visuomotor reactions, choice reaction times, and the extent of learning in the sequence reaction time task. This analysis revealed significant differences between groups of subjects, indicative of significant functional differences between the groups. It is suggested that individual differences at the initial stage of sequence learning depend mainly on the functional and structural complexity of the internal representation of the sequence, as well as by the working memory processes supporting the identification of a specified sequence of visual stimuli and performing the transformation of abstract representations into sequences of motor commands.