Representation-specific recruitment: Bidirectional interactions between working memory and perception for motion direction and face identity

The sensorimotor recruitment model posits that visual working memory (VWM) recruits sensorimotor cortices to support the maintenance of simple visual features. Here, using two naturalistic stimuli: motion direction and face identity, we show that VWM recruitment is not limited to sensorimotor areas, but instead engages any area dependent on the task demands - representation-specific recruitment. In an orthogonal dual-task paradigm, participants maintained information while performing perceptual discriminations. There are two discrimination conditions, where the stimulus being maintained in memory is either in between (middle) or to one side (side) of the discrimination stimuli in the feature space (Teng & Kravitz, Nature Human Behaviour, 3, 827-836, 2019). We hypothesized, pre-registered, and found that the middle condition reduces the perceived difference between the two motion directions and face identities, resulting in a higher discrimination threshold, whereas the side condition results in a greater perceived difference and lower thresholds. Moreover, the discrimination stimuli introduced systematic biases in the continuous recall of the maintained information. The bidirectional interference between VWM and ongoing perception supports the representation-specific recruitment model of VWM maintenance. This phenomenon was observed here for high-level features: motion direction and face identity. Such representation-specific recruitment suggests that VWM relies on different neural substrates depending on the information being maintained, contradicting a conceptualization of it as a unitary process.