Temporal Judgments of Immediate and Delayed Consequences of Self-Initiated Movements Cheryl M. Glazebrook University of Toronto Claudia Gonzalez and Jim Lyons McMaster University Digby Elliott McMaster University and Liverpool John Moores University This study was designed to examine the impact of a delay between a self-initiated movement and a subsequent auditory event on temporal judgements of movement or sound onset. Participants watched a red dot move in a clockwise direction around a circle displayed on a computer screen and reported when they had pressed the spacebar or heard a tone. In other conditions, the movement and tone both occurred. Specifically, the tone followed the button press either immediately or after delays of 100, 250, or 400 ms. On some trial blocks, participants were asked to judge the time of the button press and on other blocks the time of the tone. When the tone occurred alone, participants’ judgements were accurate. When the movement occurred alone participants exhibited an anticipatory bias. Although a delayed tone had a modest impact on judgements movement initiation, button press judgements were anticipatory in all tone delay conditions. Thusly temporal judgements associated with event binding are affected more by voluntary action than the auditory consequences of that action. Keywords: temporal binding, sensory integration, movement planning A large body of work on the awareness of self-initiated actions indicated that most people believe they initiated a movement earlier than they actually had (e.g., Haggard & Cole, 2007; Haggard, Newman, & Magno, 1999; Obhi & Haggard, 2004). This anticipatory awareness is thought to reflect our conscious percep- tion of movement preparation processes, or the hypothesised ef- ference copy, instead of movement initiation per se (Blakemore, Wolpert, & Frith, 2002; Haggard, 2005). Anticipatory awareness has been of interest to motor control researchers because this phenomenon provides insight into conscious experience and per- ception of our own movement plans (Davidson & Wolpert, 2005; Haggard & Clark, 2003; Leube et al., 2003; Voss, Ingram, Haggard, & Wolpert, 2006). The original task used to examine the relationship between neural preparation for movement and conscious awareness of the intention to move required participants to remember the time displayed on a clock when they first noticed the desire to move or when they initiated a simple key press (Libet, Gleason, Wright, & Pearl, 1983). Since this early work, findings using a variety of other tasks remain consistent with the idea of an anticipatory awareness of self-generated movements. For example, Dassonville (1995) presented a brief tactile stimulation just before, during, or just after a rapid aiming movement to a visual target. Following each trial, participants were asked to reproduce the position of their arm when the stimulation was presented. Consistent with the anticipatory awareness phenomenon, participants judged their limb to be further along than it really was when the tactile stimulation occurred. In addition, Azuma and Haggard (1999) found partici- pants released a button before their arm swept through a target. In both cases, the updated information used for sensory-motor pro- cessing was  90 ms ahead of the actual position. The timing of a self-initiated movement can also affect temporal judgements about associated sensory events. Using a variation of the original clock task, Haggard, Clark and Kalogeras (2002) presented an auditory stimulus (a beep) either 250, 450, or 650 ms after the button press. Of interest was the impact of the self- initiated movement on the judgements of when the beep occurred. When the three temporal delays were presented in a blocked schedule, Haggard et al. (2002) found that the perceptual experi- ence associated with the tone shifted toward the button press by 97 ms in the 250-ms delay condition. This perceptual shift diminished to 35 ms and 11 ms with delays of 450 and 650 ms, respectively. These findings are consistent with the notion that if the temporal interval between the two events is modest, humans perceptually bind actions and their sensory consequences into a single event. What Haggard et al. (2002) failed to examine was the impact of the auditory signal on the judgement of movement initiation. If, in perceptual binding, a voluntary action and its’ sensory conse- quences are given equal weight, then one would expect to see a similar shift in auditory and motor judgements when the two events are paired. Any asymmetry in these biases compared to Cheryl M. Glazebrook, Department of Physical Therapy, University of Toronto; Claudia Gonzalez and Jim Lyons, Department of Kinesiology, McMaster University; Digby Elliott, Department of Kinesiology, McMaster University and School of Sport and Exercise Sciences, Liver- pool John Moores University. This work was supported by the Natural Sciences and Engineering Research Council of Canada and the Canada Research Chair Program. Correspondence concerning this article should be addressed to Digby Elliott, School of Sport and Exercise Science, Liverpool John Moores University, Liverpool, England L3 2ET. E-mail: D.Elliott@ljmu.ac.uk Canadian Journal of Experimental Psychology © 2010 Canadian Psychological Association 2010, Vol. 64, No. 2, 102–106 1196-1961/10/$12.00 DOI: 10.1037/a0018308 102