Cross-modal interference-control is reduced in childhood but maintained in aging: a cohort study of stimulus-and response-interference in cross-modal and unimodal Stroop tasks

Interference-control is the ability to exclude distractions and focus on a specific task or stimulus. However, it is currently unclear whether the same interference-control mechanisms underlie the ability to ignore unimodal and cross-modal distractions. In two experiments we assessed whether unimodal and cross-modal interference follow similar trajectories in development and aging and occur at similar processing levels. In Experiment 1, 42 children(6-11 years), 31 younger adults (18-25 years) and 32 older adults (60-84 years) identified colour rectangles with either written (unimodal) or spoken (cross-modal) distractor-words. Stimuli could be congruent, incongruent but mapped to the same response (stimulus-incongruent), or incongruent and mapped to different responses (response-incongruent), thus separating interference occurring at early (sensory) and late (response) processing levels. Unimodal interference was worst in childhood and old age; however, older adults maintained the ability to ignore cross-modal distraction. Unimodal but not cross-modal response interference also reduced accuracy. In Experiment 2 we compared the effect of audition on vision and vice versa in 52 children (6-11 years), 30 young adults (22-33 years) and 30 older adults (60-84 years). As in Experiment 1, older adults maintained the ability to ignore cross-modal distraction arising from either modality and neither type of cross-modal distraction limited accuracy in adults. However cross-modal distraction still reduced accuracy in children and children were more slowed by stimulus-interference compared with adults. We conclude that; unimodal and cross-modal interference follow different lifespan trajectories and differences in stimulus- and response-interference may increase cross-modal distractibility in childhood