Optional stopping on nonstationary series

Two experiments were run to investigate optional stopping behavior where the offers came from different types of series. Subjects attempted to choose the maximal offers by looking through stacks of seven cards in a situation of sampling without recall. In the first experiment subjects were provided with full information on the nature of the series regarding the form of the distribution, its variance and its trend (i.e., descending, constant, or ascending). In the second experiment subjects were presented with probabilistic information on the type of series. The results indicate that the trend of the series does not affect the proportion of optimal decisions. However, various kinds of series lead to different types of errors. Also, the proportion of optimal decisions is higher when subjects have full information rather than probabilistic information on the type of the series. The results are discussed in terms of normative search theory, heuristic information processing, and choice behavior.