When actions speak louder than words: The Final Position Judgement Task involves action imagery rather than verbal rehearsal

In the Final Position Judgement Task, participants imagine performing auditorily instructed movements and compare their imagined final position with a visual stimulus. Although participants are instructed to imagine the visual and kinesthetic sensations associated with the movements, they may verbally rehearse the instructions rather than generating an imagery, manipulating it according to the instructions, maintaining it, and subsequently inspecting it. To examine the involvement of action imagery and verbal rehearsal, participants completed the Final Position Judgement Task once in a baseline condition and once under articulatory suppression in a within-subjects design. The involvement of action imagery and verbal rehearsal was evaluated based on self-reported strategy use, associations with working memory components and behavioral measures of action imagery ability, as well as task performance. Accuracy in final position judgements was related to visuospatial sketchpad capacity but unrelated to phonological loop capacity. Most participants relied on visual rehearsal, whereas verbal rehearsal served a supporting role but did not benefit performance in final position judgements. Articulatory suppression appeared to impair action imagery rather than enhancing its use. Together, these findings support the use of the Final Position Judgement Task as an objective measure of action imagery ability, provided open-source alongside the manuscript.