The mechanisms of far transfer from cognitive training: specifying the role of distraction suppression

Cognitive training aims to produce a durable transfer to untrained abilities (i.e., far transfer). However, designing effective programs is difficult, because far transfer mechanisms are not well understood. Greenwood and Parasuraman (Neuropsychol 30(6):742-755. https://doi.org/10.1037/neu0000235 , 2016) proposed that the ability to ignore distractions is key in promoting far transfer. While the authors identified working-memory training based on the N-back task as an effective way to train distraction suppression, a recent meta-analysis concluded that this form of training rarely produces far transfer. Such inconsistency casts doubt onto the importance of distraction suppression in far transfer and calls for further examination of the role of this ability in cognitive training effectiveness. We propose here to conceptualize distraction suppression in the light of the load theory of attention, which distinguishes two mechanisms of distractor rejection depending on the level and type of information load involved: perceptual selection and cognitive control. From that standpoint, N-back training engages a single suppression mechanism, namely cognitive control, because it mainly involves low perceptual load. In the present study, we compared the efficacy of N-back training in producing far transfer to that of a new response-competition training paradigm that solicits both distraction suppression mechanisms. Response-competition training was the only one to produce far transfer effects relative to an active control training. These findings provided further support to Greenwood and Parasuraman's hypothesis and suggest that both selection perception and cognitive control need to be engaged during training to increase the ability to suppress distraction, hence to promote far transfer.