Contrasting frameworks of multi-attribute decision making: Multiple strategies, connectionist network, or evidence accumulation?

Every day, decision makers are confronted with a multitude of different choice problems and situations. Most researchers in the field of multi-attribute decision making agree that decision makers adapt their behavior to these varying circumstances, but the question how this adaptation is achieved has been answered in fundamentally different ways. Whereas the multiple strategy framework assumes that decision makers select one of the multiple qualitatively different decision strategies contained in the decision makers’ (mental) toolbox, single-process frameworks propose a single uniform mechanism for decision making. The nature of this mechanism, however, is modeled in different ways by different frameworks. The work presented in this thesis contrasted three frameworks of multi-attribute decision making to determine which one describes decision making from given information best. The first project (Sollner, Broder, & Hilbig, 2013) concentrated on the parallel constraint satisfaction (PCS, Glockner & Betsch, 2008a) model for multi-attribute decision making, representing the connectionist network framework that assumes parallel integration of all applicable information within a neural network structure. Varying the format of openly presented information, PCS was contrasted with prominent decision strategies from the competing multiple strategy framework. PCS gave a superior account for individual decision behavior when information search was reduced to a minimum. However, as soon as the format of information presentation necessitated some extent of information search, individual decision behavior did not comply with PCS’ predictions for the majority of participants. Thus, the adequacy of PCS to describe decision making from given information seems to crucially depend on the immediate accessibility of all relevant information. The second project (Sollner, Broder, Glockner, & Betsch, 2014) contrasted the multiple strategy framework with the evidence accumulation framework and the connectionist network framework that both propose a single uniform mechanism for decision making. The project built on the multiple strategy framework’s prediction that decision makers employing a frugal decision strategy will ignore strategy-irrelevant information, whereas the single-process frameworks hold that all relevant information will be fed into the proposed mechanism. To test these competing predictions, the information intrusion paradigm was developed that confronted participants with valid, but strategy-irrelevant information. As a result, participants did not ignore the additional information, but consistently adjusted their decision behavior (choices, information search, confidence judgments). The observed failure to ignore strategy-irrelevant information is in line with the assumption of a uniform mechanism that integrates all applicable information. Finally, the third project (Sollner & Broder, 2014) focused on the process of information search and, in particular, the stopping behavior as predicted by the multiple strategy framework and the evidence accumulation framework. The latter assumes that decision makers sample information until the accumulated evidence in favor of one option passes the individual evidence threshold and they choose the respective option. Participants were presented with varying levels of evidence in favor of one option within a half-open-half-closed information display and their subsequent information search was monitored. The conducted analyses unanimously supported the evidence accumulation framework’s predictions: Analyses in the aggregate revealed that the percentage of immediate stopping increased with increasing levels of given evidence – a finding that is in line with the evidence accumulation framework, but not predicted by the multiple strategy framework for the employed stimuli. Moreover, on an individual level, the termination of information search was not well-captured by the different stopping rules (currently) contained in the multiple strategy framework, but confirmed the notion of an individual evidence threshold. In sum, all three projects support the suitability of the single-process frameworks to describe decision making from given information. The reported evidence challenges the popular multiple strategy framework, but simultaneously demands further theoretical development of its successful competitors – the evidence accumulation framework as well as the connectionist network framework.