[Stimulus and reaction patterns in serial choice reactions].

In serial choice-reaction-tasks reaction times decrease faster if the sequence of stimuli is structured rather than of being random. Nevertheless, the issue whether this structure-specific improvement of performance is due to the structure of the stimulus- or the response-sequences is controversially discussed. After a review of the corresponding literature, an experiment will be reported which was designed to contribute to this issue. Contrary to the present experiments, which exclusively analysed effects of statistical redundancy, relational patterns are introduced into the sequences of stimuli as well as into the sequences of responses. These relational patterns were varied independently of each other. The data reveal strong effects of the relational patterns in the sequence of responses, whereas the relational patterns of the stimulus sequences were not systematically effective. Furthermore, the data suggest that the relational structure of the response sequences especially favours the formation of "motor-chunks". In the discussion it is emphasized that effects of relational patterns on serial choice reactions are not yet adequately regarded, neither in experimental research nor in the theoretical accounts.