The Perseveration Effect in Individuals' Strategy Choices

This doctoral dissertation consists of a series of four manuscripts in which we investigated the influence of the previously used strategy on the subsequent strategy choice (i.e., the so-called perseveration effect). Although sequential effects have already been widely studied in a variety of research domains, they have scarcely been investigated with respect to individuals' strategy choice behaviour. All reported experiments in this dissertation relied on the same experimental task, namely the numerosity judgement task. The goal of this task is to determine various numerosities of coloured cells in a rectangular 5 x 10 grids. Participants can choose between two strategies to solve the different problems: an addition strategy (i.e., adding the coloured cells individually or groupwise) and a subtraction strategy (i.e., adding the empty cells individually or groupwise and subtracting this number from the grid size). The dissertation starts with a general introduction in which we provide a background about multiple strategy use, sequential effects in other research domains, and the numerosity judgement task. In Chapter 1, we report the first experiments that tested this perseveration effect in strategy choices. Therefore, sequences were built in which test items (that were assumed to elicit both strategies) were preceded by addition items or subtraction items that only elicited the addition or the subtraction strategy, respectively. We selected these test items from both a broad (first experiment) and a small numerosity range (second experiment). The results confirmed the hypothesized perseveration effect, that is, participants chose more often for the subtraction strategy after the multiple use of the subtraction strategy than after the multiple use of the addition strategy. However, it was also found that the effect was limited to these numerosities for which both strategies were more or less equally applicable. The goal of the following experiment, reported in Chapter 2, was to replicate the findings observed in the first two experiments with a different research paradigm. In this experiment, we manipulated the presentation order in which the different numerosities were presented (i.e., an ascending, a descending, and a random order). Also with this research paradigm, we were able to show the perseveration effect. Common to the experiments of Chapter 1 and Chapter 2 is that they all showed the perseveration effect after a repeated use of the previous strat