Ego depletion moderates the relationship between pain-related threat and attentional bias to pain-related stimuli

Abstract

Background: Pain demands attention. As pain becomes chronic, physical and/or psychological exhaustion (e.g. ego depletion) occurs. Given that attention resources are limited, it is not known how attention patterns for pain-related stimuli occurs in a state of ego depletion. We aimed to examine the effects of pain-related threats and ego depletion on attentional patterns for pain-related stimuli. Methods: Twenty-nine college students in Daejeon, Korea were randomly assigned to receive either high or low level of pain-related threat, each of which included high and low ego depletion subgroups. Participants' eye movements were measured during a viewing task that featured sensory pain-neutral, affective pain-neutral and neutral–neutral word pairs. We conducted 2-way ANOVAs (pain-related threat by ego depletion) on attentional bias indices. Findings: The low threat group had longer first fixation on pain-related words than neutral words, whereas the high threat group showed the opposite result. The high ego depletion group viewed pain-related words longer than the low ego depletion group. In the low ego depletion group, participants receiving low pain-related threat had a faster first fixation to neutral words than pain-related words, whereas those receiving high pain-related threat showed the opposite result. However, in the high ego depletion group, participants had a faster first fixation to pain-related words than neutral words, regardless of pain-related threat. Discussion: We confirmed the moderating effects of the ego depletion on the relationship between the pain-related threat and attentional bias to pain-related stimuli. This implies the importance of ego depletion in the attention process of pain.