Alexithymia slows performance but preserves spontaneous semantic decoding of negative expressions in the emostroop task

Alexithymia is a multifaceted personality construct related to deficits in the recognition and verbalization of emotions. It is uncertain what causes alexithymia or which stage of emotion processing is first affected. The current study was designed to determine if trait alexithymia was associated with impaired early semantic decoding of facial emotion. Participants performed the Emostroop task, which varied the presentation time of faces depicting neutral, angry, or sad expressions before the classification of angry or sad adjectives. The Emostroop effect was replicated, represented by slowed responses when the classified word was incongruent with the background facial emotion. Individuals with high alexithymia were slower overall across all trials, particularly when classifying sad adjectives; however, they did not differ on the basic Emostroop effect. Our results suggest that alexithymia does not stem from lower-level problems detecting and categorizing others' facial emotions. Moreover, their impairment does not appear to extend uniformly across negative emotions and is not specific to angry or threatening stimuli as previously reported, at least during early processing. Almost in contrast to the expected impairment, individuals with high alexithymia and lower verbal IQ scores had even more pronounced Emostroop effects, especially when the face was displayed longer. To better understand the nature of alexithymia, future research needs to further disentangle the precise phase of emotion processing and forms of affect most affected in this relatively common condition.