Context dependencies in decision making

Irrelevant information should not affect our decisions. Yet, our choices are often swayed by contextual input that is entirely unrelated to the decision at hand. This is true for perceptual judgments pertaining to the appearance of a visual stimulus, as well as for more abstract evaluations of economic prospects. My thesis examines three specific instances of context-dependent behavior across the realms of perception and economics. Across all studies, I charted the behavioral signatures of context-dependent choices via careful experimental manipulation. I combined this behavioral data with simulations of mathematical models to arbitrate between different theoretical accounts of the mechanisms underlying context-dependent decision making. My first study investigated how the context provided by an additional (decoy) alternative sways economic choice between two target options. It mapped decoy influence across the full attribute space of possible decoy definitions. My second study examined the influence that an irrelevant distractor stimulus wields on perceptual decisions. It combined psychophysical measurement with regression-based and reverse correlation analytic approaches to shed light on the functional form of distractor effects. Finally, my third study probed the mechanisms driving context-dependent categorization decisions. It measured the contributions of putative drivers of contextual influence combining novel analytic techniques with experimental design controlling for potential confounds. Across the three studies, normalization-based information processing schemes emerged as a common theme. Viewed through the normative lens of efficient neural coding, normalization provides a compelling account for the observed patterns of context-dependent choice behavior