Coupling of action-intention binding is reduced in aphantasia

The sense of agency (the feeling of being the cause of one's own actions) is thought to arise from reliability-weighted integration of multiple cues across the intention-action-outcome sequence. Whether integration is coordinated across the stages of this sequence or carried out independently at each stage remains unknown. Using the Libet clock intentional binding task in 578 participants spanning the aphantasia-to-hyperphantasia spectrum, we examined the correlation between action binding and intention binding as an index of this coordination. At the group level, negative coupling between individuals' action and intention binding was present in typical imagers (r = -0.27, p < .001), but was not present in core aphantasia, where voluntary visual imagery is entirely absent (r = -0.05, p = .44). Coupling differed significantly between these two groups, even though neither binding component differed between them. Individuals with weak but present imagery (hypophantasia) showed a distinct binding profile, with intention binding exceeding action binding magnitude, a pattern absent in all other groups. Together these findings suggest that it is the coordination of integration across the action sequence, rather than the strength of individual binding components, that distinguishes those with and without voluntary imagery.