Abstract: Uncertainty and prediction error play important roles in the initiation and regulation of emotions, and may serve as critical determinants of emotional intensity. Previous studies have suggested that emotional intensity may result from the combination of the value of arousal and valence. However, it remains unclear how uncertainty and prediction error influence these two dimensions independently or jointly, and how such influences further shape emotional intensity. Therefore, the present study aims to systematically examine the effects of uncertainty and prediction error on arousal and valence, and further explore their roles in emotional intensity.
The present study conducted two experiments, using a card-gambling task adapted from the cue-target paradigm. Experiment 1 investigate how uncertainty and prediction error affect emotional responses at the subjective and physiological levels, with combined behavioral measures and eye-tracking techniques. Experiment 2 examine their differential influences on arousal and valence at the neural level using functional magnetic resonance imaging (fMRI). A total of 36 valid participants were included in Experiment 1, and 16 valid participants were included in Experiment 2.
The results in experiment 1 showed that uncertainty and prediction error had significant interactive effects on arousal ratings and pupil dilation responses. Under low-uncertainty conditions, unexpected outcomes elicited higher arousal and greater pupil dilation than expected outcomes, whereas these differences were attenuated under high uncertainty. In contrast, the pattern observed in valence differed from that found for arousal and pupil responses, suggesting that uncertainty and prediction error may influence different components of emotion in distinct ways. The results in experiment 2 identified condition-dependent neural responses associated with uncertainty and prediction error. In addition, the interaction between uncertainty and prediction error engaged a distributed network of brain regions, including the superior frontal gyrus, middle frontal gyrus, anterior cingulate gyrus, caudate nucleus, putamen, and brainstem.
In conclusion, these results suggest that the influence of uncertainty and prediction error on emotional intensity is based on their different effects on arousal and valence. High uncertainty may impair the formation or precision of prediction error, thereby affecting subjective emotional experience and physiological responses. By integrating behavioral, eye-tracking, and neuroimaging evidence, the present study provides convergent support for the cognitive and neural mechanisms through which uncertainty and prediction error shape emotional experience, and thus offers a useful perspective for future research on stress and emotion regulation.

Key words: prediction error, uncertainty, arousal, valence, emotional intensity