The effects of image hue and semantic content on viewer's emotional self-reports, pupil size, eye movements, and skin conductance response

A study was conducted in order to examine the emotional effects of content and hue interacting in the same image. To achieve this goal, self-reported (based on Self-Assessment Manikin [ SAM] scale), physiological (pupil diameter and skin conductance response), and behavioral (eye movement) measures were used in response to a set of photographs selected from the International Affective Picture System (IAPS). Each of them was a combination of 1 type of content (natural or urban) and 1 type of image version (original, grayscale, green, or red). The results revealed that participants' emotions were dependent on specific contents, hues, and content X hue interactions. The natural content elicited more positive and less arousing emotions compared to the urban one. Green images were less arousing compared to red ones, and original images elicited the most pleasant emotions. Moreover, green was the only hue for which valence effects of content were observed-the natural content-green color combination elicited more positive emotions compared to the urban content-green color combination. Results emerging from the different measures are connected to each other and interpreted in the framework of cognitive fluency. Pupil dilation on the one hand, and eye movements and fixations on the other hand, which respectively provided data on vegetative responses and visual search strategies, were often found to embody the emerging emotional experience.