Attractiveness effects on search: Validating an iCodes parameter

The integrated coherence-based decisions and search model (iCodes) predicts that participants show a tendency to search for information on the option currently supported by the already available evidence, a prediction coined as the attraction search effect. While this search tendency could be shown to be robust, the data also showed considerable interindividual variability in the attraction search effect. One explanation could be that the relative strength of the attractiveness influence on search varies between situations and participants. Within iCodes, the relative strength of option attractiveness on the information-search process is represented by the γ parameter. In this project we experimentally manipulated between-subjects participants’ awareness of differences in attractiveness of the choice options by asking the experimental group to rate option attractiveness before search. Indeed, rating options’ attractiveness increased the tendency to search for the more attractive option compared to not rating options’ attractiveness. The effect of these ratings was further reflected in individually fitted γ parameters: Parameter values of participants who rated option attractiveness showed that their search was influenced more strongly by attractiveness than participants in the control group. The results of this project corroborate the role of the γ parameter and that iCodes is able to capture the effect of a theoretically-motivated manipulation of information-search behavior. Thus, this project further validates the assumed information search process and emphasizes the role of the already available evidence in information search but also takes systematic differences in the size of the effect into account.