Investigating hemispheric specialization in a novel face-word Stroop task

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psycholinguistics

Background:

• Hemispheric specialization describes the differing roles of the left and right brain hemispheres.
• The Stroop task traditionally reveals interference when word meaning conflicts with visual processing.
• Emotional stimuli, like facial expressions and emotion words, engage distinct neural pathways.

Purpose of the Study:

• To investigate hemispheric specialization during a lateralized Stroop facial identification task.
• To examine the conflict between right-hemispheric emotional processing and left-hemispheric verbal processing.
• To determine if sex influences performance in this task.

Main Methods:

• A 2x2x3 factorial design was employed, manipulating presentation side (left or right visual field), picture emotion (happy or angry), and distractor word emotion (happy, angry, or blank).
• Participants identified the emotion of briefly displayed faces while incongruent or congruent emotion words were presented.
• Stroop interference was measured by accuracy and reaction times.

Main Results:

• Greater Stroop interference in identification accuracy occurred with incongruent facial expressions in the left visual field and emotion words in the right visual field.
• Females exhibited significantly less Stroop interference compared to males.
• Reaction times were influenced by both emotion type and visual field presentation.

Conclusions:

• The findings support the hypothesis of right hemispheric specialization for emotional expression processing and left hemispheric specialization for verbal processing.
• Sex differences in emotional processing and hemispheric interaction were observed.
• This study highlights the complex interplay between visual field, emotional stimuli, and verbal information in cognitive tasks.