Get’cha Head in the Game: Testing Context Effects for Naturalistic Stimuli in Basketball

Leading theories of subjective probability judgments (SPs) model SPs in terms of the support, or strength of evidence, assigned to a focal hypothesis relative to the support of alternative hypotheses. These theories assume that each hypothesis elicits a fixed level of support regardless of the other hypotheses under consideration. Contradicting this idea, recent research on SPs has found context effects – changes in support for one hypothesis based on the other hypotheses under consideration (Cai & Pleskac, 2023). However, these results were obtained using artificial stimuli in laboratory settings. Do context effects in belief occur in naturalistic forecasting environments? To investigate this, we conducted a study where N = 113 participants judged the likelihood of the final ranking of the men’s NCAA basketball teams one month out. The study occurred in two phases. First, participants were asked to map 50 basketball teams onto a two-dimensional space using a Spatial Arrangement method. Then, based on their mental representations, we presented customized triplets of teams designed to elicit context effects in each participant and asked them, across 180 trials, to judge the probability of one team ranking higher than the other two in the NCAA’s final rankings. Our findings suggest that similarity and attraction effects can occur in this naturalistic environment, and there is some evidence of a compromise effect. These results invalidate the support invariance principle, which rules out a large class of psychological theories of subjective probability judgments that assume this principle. Furthermore, they suggest that belief and preference construction may be driven by similar processes.