Is Zero Void? Attentional Mechanism of Hidden-zero Effect in Risky Decision-making

The frame of risky choice could alter and shape an individual’s risky preferences. Within an option of typical risky choice, that is, "p% chance to win Q dollar," naturally embedded a hidden-zero outcome, namely, "(1-p)% chance to win 0 dollar." Despite its pervasive existence, there is insufficient evidence of the existence or a cognitive mechanism of the hidden-zero effect in risky choice. To this end, we proposed an attentional based risk-aversion model for behavior and process level to interpret the mechanism of the hidden-zero effect. We presented participants’ explicit or hidden-zero outcomes in pairs of certain versus risky options and measured their choice preferences and eye-movement characteristics. We observed that participants were less risk avoidant in the explicit-zero condition than in the hidden-zero condition, and a descriptive attentional bias shifted this preference to favor certain options in the hidden-zero condition (Study 1). We further combined the eye-tracking data with hierarchical Bayesian modeling (Study 2). We observed that a model combining behavioral and process attention provided better predictions regarding participants’ preference. When presenting zero outcomes, an empirical attentional bias integrating eye-movement features indicated that attention plays a central role to alter the attention allocation and consequent choice preference from certainty options to risky options in risky decision-making. These findings highlight the potential mechanism of the hidden-zero effect in risk decision-making on cognitive and computational levels.