Abstract
Vision and audition are the two primary modalities along which people can express emotional experiences. During the past two years, we have constructed an affective database where brief episodes of emotional exchange, which to a large extent emulates the real-life scenarios of emotional exchange, are created. Here we aim to create a psychophysical scale so that sample of affective episodes selected from the database can provide a precise, quantitative reference when using them for future research. Specifically, we adopted Thurstone’s paired-comparison method where pairs of selected videos were compared to derive their psychophysical scaling values. Thirty-eight participants were recruited. Ten short videos with differential intensity conveying emotional expressions of six categories (i.e., happiness, sadness, anger, surprise, disgust, and fear) were paired randomly in a sequential presentation on each trial. Participants had to decide which of the pair expressed a stronger emotion of a given category. A total of 270 trials were administered. The trials were blocked according to emotional category, and the order of category was randomly administered. The results showed that the mean scaled value varied from 0.57 for videos depicting sadness to 1.97 for those depicting surprise, indicating that the range of affective scaling was somewhat constrained. Moreover, we found that the scaled values were highly correlated with previous measurements based on ratings of emotional intensity from another large group of participants for emotional expressions of happiness, anger, surprise and disgust. Furthermore, scale values for anger, surprise, and disgust were significantly, though negatively, correlated with their entropy measures. Taken together, the overall dynamic affective database can be a useful source of stimuli for investigating emotional processing and integration across two modalities, and the psychological scaling of the database can further offer precise quantitative measurements and references that may be required by specific research.