Experiments and models in sequential integration of information

Using the example of bimodal temporal order judgments, we investigate and explain the transition from static designs mapping single stimulus presentations to single responses to designs which require some kind of integration of the processed information. First, we estimate the parameters of several well-known channel-oriented models (Baron, 1969; Gibbon & Rutschmann, 1969) for temporal order judgments. Subsequently, we generalize these models to explain the results of two more complex experimental designs and derive and test their predictions. Special concern is given to the question whether or not the models parameters remain invariant across the experiments. The basic assumptions of the channel-oriented models are confirmed by our data, they represent a well-suited platform to explain more complex integrative processes. Within a sequential decision design, where subjects are allowed to observe a stimulus arbitrarily often before their terminal decision, the individual representations of the stimuli are additively integrated. Hence, even information, which did not yet lead to a terminal decision, will generally influence the later outcome. This representation of the stimuli is accompanied by a dynamic decision rule, which is clearly time-dependent. Several too simplizistic alternative models can be rejected if (and only if) one derives their predictions in some detail and tests them with sufficient statistical power.