Dynamische und strukturelle Aspekte der Selektion von ...

IV Summary
One of the central processing stages linking perception and action is response selection
(e.g. Lien & Proctor, 2002). Response selection can be described as a mechanism translating
stimulus into response representations in a way, which allows adaptive behavior with respect
to the given situation and the individual goals. In the two studies of this dissertation, a dynamic,
control-related (Study I) and a structural, representation-related (Study II) aspect of response
selection were studied thoroughly. Therefore, the effects of response category repetitions
under task shift conditions were analyzed.
In the first study, it should be answered, whether response execution, selection or
merely activation in the previous task are necessary for observing the respective repetition
effects, and to what extent these effects are modulated by the actual risk of possible accidental
response reexecutions. The answers to these questions served to test, whether learning or reconfiguration
mechanisms suffice to explain response-only repetition effects, or whether an
additional inhibitory control mechanism needs to be assumed. The results of this first study
show, that the respective repetition effects a) depend only on response activation processes
and b) are modulated by adaptive adjustment mechanisms. These results suggest the assumption
of an inhibitory control mechanism, which is triggered by potential response conflicts.
The second study focused on the response categories, which are relevant for response
selection, and the factors determining the choice of a specific category type. It should be
answered, whether the participants represent the responses according to the relevant stimulus
dimensions, or according to some abstract, response-immanent features. The results of the second
study show that the responses are generally represented according to abstract response
features (e.g. index / middle finger). Furthermore, the instructions proved to be crucial as to
which of several equally possible category types are indeed used for response representation,
but only if the alternative category type (e.g. left / right) is not induced by overlapping implicit
stimulus features.
Altogether the results of the present studies support a) the notion that response selection
consists of several subprocesses (automatic response activation, intentional S-R-translation
and control mechanisms) and b) models postulating an additional layer of abstract response
categories besides the stimulus category layer (e.g. Zhang, Zhang & Kornblum, 1999).