Schedule of Events | Symposia

The Confused Body: How Uncertainty Shapes Somatic Markers and Decision-Making

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Mianzhi Hu¹ (zuirenlangzi@gmail.com), Darrell Worthy¹; ¹Texas A&M University

The somatic marker hypothesis suggests that decision-making is guided by bodily memories of past experiences, which predict the outcome of selecting a given option by reinvoking the physiological states associated with previous outcomes of the same option, thereby steering people towards advantageous choices and away from disadvantageous ones. However, it falls short of explaining recent evidence showing that normal individuals without neuropsychological deficits nevertheless prefer less rewarding options when these options are paired with greater certainty (e.g., higher reward frequency). We examined whether the direction and strength of somatic markers are modulated by environmental uncertainty, rather than being objectively calibrated by past outcomes. Participants completed a four-option reinforcement learning task under one of three conditions: a baseline condition with low reward variance and equal reward frequency, a frequency condition with low variance but unequal reward frequency, and a variance condition with high reward variance and equal reward frequency. Our findings revealed that when participants were comparing closely valued options, uncertainty—arising from either low reward frequency or high reward variance—nullified, if not reversed, the anticipatory Galvanic skin conductance differences between optimal and suboptimal options. Moreover, we observed that high uncertainty reduced the overall physiological responsiveness of the somatic marker. While high uncertainty typically elicited stronger anticipatory somatic markers, excessive environmental uncertainty weakened the markers’ overall strength, resulting in a generally muted bodily state. These findings suggest that somatic markers may function as a bodily indicator of established preferences but are less effective in accurately reflecting past outcomes under high uncertainty.

Topic Area: THINKING: Decision making