How affordance similarity impacts µ rhythm desynchronization during object selection.

Visual scenes typically contain multiple objects, each evoking potential actions ("object affordances"). Studies demonstrated that when several objects are presented, the similarity of their affordances can slow perceptual judgments. Here, we investigated whether the cost of affordance similarity is reflected at the neural level. We aimed to better identify how and when the similarity of affordances impacts the activity of the motor neural network, through µ rhythm desynchronization. We also investigated the influence of thematic relations between objects on this phenomenon. Forty participants named a target object in 3D scenes displaying object pairs while EEG was recorded. Objects were designed to evoke either power or precision grips, with pairs varying in affordance similarity and thematic relatedness. After a preview of the scene, a cue indicated the target object to name. Modulations of µ rhythm desynchronization according to affordance similarity and thematic relations were analyzed over time. We observed reduced μ rhythm desynchronization during target selection when related objects shared similar affordances, an effect absent when objects were unrelated. These findings demonstrate that affordance similarity negatively impacts neural motor resonance during object selection, and that semantic relations modulate this effect.