Effects of touch on emotional face processing: A study of event-related potentials, facial EMG and cardiac activity

- Effects of emotional faces on ERPs, EMG and ECG are comprehensively replicated.
- Tactile and auditory stimuli presented before the faces affect the same measures.
- However, the type of prime does not interact with the type of emotional expression.
- Simple tactile primes do not bias emotional evaluation.

Being touched is known to affect emotion, and even a casual touch can elicit positive feelings and affinity. Psychophysiological studies have recently shown that tactile primes affect visual evoked potentials to emotional stimuli, suggesting altered affective stimulus processing. As, however, these studies approached emotion from a purely unidimensional perspective, it remains unclear whether touch biases emotional evaluation or a more general feature such as salience. Here, we investigated how simple tactile primes modulate event related potentials (ERPs), facial EMG and cardiac response to pictures of facial expressions of emotion. All measures replicated known effects of emotional face processing: Disgust and fear modulated early ERPs, anger increased the cardiac orienting response, and expressions elicited emotion-congruent facial EMG activity. Tactile primes also affected these measures, but priming never interacted with the type of emotional expression. Thus, touch may additively affect general stimulus processing, but it does not bias or modulate immediate affective evaluation.