Neural tracking of subjective value under riskand ambiguity in adolescence

Abstract

Although many neuroimaging studies on adolescent risk taking have focused on brain activation during outcome valuation, less attention has been paid to the neural correlates of choice valuation. Subjective choice valuation may be particularly influenced by whether a choice presents risk (known probabilities) or ambiguity (unknown probabilities), which has rarely been studied in developmental samples. Therefore, we examined the neural tracking of subjective value during choice under risk and ambiguity in a large sample of adolescents (N = 188, 12-22 years). Specifically, we investigated which brain regions tracked subjective value coding under risk and ambiguity. A model-based approach to estimate individuals' risk and ambiguity attitudes showed prominent variation in individuals' aversions to risk and ambiguity. Furthermore, participants subjectively experienced the ambiguous options as being riskier than the risky options. Subjective value tracking under risk was coded by activation in ventral striatum and superior parietal cortex. Subjective value tracking under ambiguity was coded by dorsolateral prefrontal cortex (PFC) and superior temporal gyrus activation. Finally, overlapping activation in the dorsomedial PFC was observed for subjective value under both conditions. Overall, this is the first study to chart brain activation patterns for subjective choice valuation under risk and ambiguity in an adolescent sample, which shows that the building blocks for risk and ambiguity processing are already present in early adolescence. Finally, we highlight the potential of combining behavioral modeling with fMRI for investigating choice valuation in adolescence, which may ultimately aid in understanding who takes risks and why.

Keywords: Adolescence; Ambiguity; Parametric; Risk; Subjective value; fMRI.

Fig. 1

Schematic representation of the fMRI task. a Example of an ambiguous trial in which the outcome after choosing to gamble was a gain. b Risky and ambiguous stimuli

Fig. 2

a Participant distribution across ages. b Violin- and box-plots for risk attitude for all participants and for three age bins. The violin plots show the full distribution of the data. 0 indicates risk aversion, 1 indicates risk neutrality, and 2 indicates risk seeking. c Violin- and box-plots for ambiguity attitude for all participants and for three age bins. – 1 indicates ambiguity aversion, 0 indicates ambiguity neutrality, and 1 indicates ambiguity seeking. For both risk and ambiguity attitudes, participants were generally averse, although there were considerable individual differences. d Relation between risk attitude and gambling under risk in the fMRI task (left) and between ambiguity attitude and gambling under ambiguity in the fMRI task. Greater risk seeking was related to higher levels of gambling under risk and under ambiguity in the fMRI task. Greater ambiguity seeking was related to higher levels gambling under ambiguity in the fMRI task

Fig. 3

a Average perceived riskiness for each of the risky wheels (left) and ambiguous wheels (right) presented in the behavioral task, plotted for three age bins. No age effects were observed. 0 indicates not all risky, and 100 indicates very risky. Bars indicate standard errors. b Partial correlations of risk attitude and the mean perceived riskiness of the risky wheels (left), and partial correlation of ambiguity attitude and the mean perceived riskiness of the ambiguous wheels (right), controlled for age. Risk attitude correlated with the perceived riskiness of both conditions, whereas ambiguity attitude correlated only with the perceived riskiness of ambiguity

Fig. 4

Whole-brain parametric results, showing t contrasts. a Subjective value (SV) under risk: positive (upper panel; y = 14; L; R) and negative (lower panel; x = – 4; R). b Subjective value under ambiguity: negative (x = – 4; R; L). The results are family-wise error cluster-corrected (p < .05)

Fig. 5

a Results of the parametric conjunction between the negative effects of subjective value (SV) under risk and ambiguity (x = – 4). The plot on the right is for visualization purposes only. b Results of the parametric SV risk > SV ambiguity (x = – 4, R; L). The results are FWE cluster-corrected (p < .05)