Mind the Hands: Holding Force Tracks Cognitive Processes

Measuring the time course of mental processes is crucial for experimental psychology, yet, popular and convenient reaction time registration with response buttons provides no dynamic data. Alternatively, traditional time-resolved methods like EEG require substantial participant compliance. Here we show that mental processes continuously influence force fluctuations when a simple force sensor is held. We measured participants’ bimanual holding force while manipulating their spatial attention either exogenously (showing lateral stars) or endogenously (showing central arrows or the words ‘left’ or ‘right’). Both early attentional shifts induced by the stimuli and later response preparation processes systematically affected holding force well before overt responding. Continuous holding force registration is thus a convenient new method for studying the dynamics of cognition.