Representation versus process in simplicity of serial pattern completion

This study deals with the question whether preferred extrapolations of serial patterns are determined by the extrapolation process or the representation of serial patterns. Three experiments are reported. The first deals with series of letters from the alphabet. Each series gave rise to extrapolations with varying frequencies, and we investigated how well these frequencies are predicted by the information loads, stemming from three models. The model of Klahr and Wallace (1970) is mainly concerned with the process of extrapolation. The model of Simon and Kotovsky (1963) describes both the process and the representation of extrapolated series. A third model is introduced here that exclusively deals with the representation of series. The outcome indirectly indicates that the preferred extrapolation is determined by the simplest representation of a series and not by the simplest process towards this representation. To strengthen the last conclusion two experiments are added dealing with bar graph stimuli. They are designed to experimentally disentangle representation and process complexity. In the second experiment the task was to judge the complexity of each series after having extrapolated the series. In the third experiment, subjects had to judge complexity of extrapolated series without the task to extrapolate the series. The predictions from the three models make plausible that the complexity judgments of second experiment reflect the process of extrapolation and the complexity judgments of the third experiment still reflect the representation of series. The latter results again support the assumption that the preferred extrapolation is determined by the simplest representation of a series.