Saturday Evening
Posters 5112 - 5115
assuming that (a) only a limited number of agents can be tracked simultaneously; and (b) only a limited period of motion trajectories can be stored in working memory. These two straightforward constraints nevertheless produce an intriguing chasing vs. stalking distinction, which matches human performance quantitatively across a variety of tasks. In contrast, a model with unlimited capacity is only sensitive to the actual efficiency of chasing, without the ‘chasing’ vs. ‘stalking’ distinction at all. These results demonstrate how perceived chasing is determined by both the domain-specific assumptions implemented in an ideal observer model and domain-general constraints from limited cognitive capacities. They provide a new perspective in understanding how attention and working memory enable rich social percepts. Email: Tao Gao,
[email protected]
that focussed on the movement of breath in the body. Finally, participants completed the temporal bisection task for a second time. The control group showed no change after the listening task. However, meditation led to a relative overestimation of durations. Within an internal clock framework, a change in attentional resources can produce longer perceived durations. This meditative effect has wider implications for the use of mindfulness as an everyday practice and a basis for clinical treatment. Email: Dinkar Sharma,
[email protected] (5114) The Phenomenology of Controlling a Moving Object With Another Person. JOHN A. DEWEY and GÜNTHER K. KNOBLICH, Central European University, THOMAS H. CARR, Michigan State University—The sense of agency (SoA) is the perception of willfully initiating and controlling an action. When acting individually, SoA depends on congruence between the predicted and actually perceived sensory consequences (action effects). However, little is known about SoA for action effects that are jointly determined by more than one actor. In two experiments, we studied how individuals’ experience of controlling a moving object was influenced by sharing control with a second person. Participants used joysticks to manipulate an object in pursuit of a moving target either with or without a co-actor. Participants’ SoA was strongly influenced by the correlation between their own joystick movements and the moving object, but also influenced (reduced) by the mere presence of a co-actor with a non-working joystick. In a second experiment, when the co-actor’s joystick was active and enhanced acquisition of the target, participants’ SoA increased. SoA during joint action is influenced by low-level visuomotor correlations, but also by the presence of competing causal influenes, and by the success of joint action goals. Email: John Dewey,
[email protected]
(5112) Separating Stimulus, Goal and Response Switching During a Fast-Paced Sustained Attention Task. BEN J. DYSON and ADAM HARLEY, Ryerson University—Previous research into sustained attention has shown the importance of goal and stimulus switching, but response switching has so far been ignored as a factor. The current study investigated the combined contributions of goal, stimulus, and response switching on performance recovery during sustained attention. 60 participants performed a fast-paced task involving a primary, a break, and a return phase, wherein the break phase involved all possible combinations of goal, stimulus and response repetition and switch across separate blocks. In accordance with the recommendations of the literature, reaction time, commission errors and omissions errors were all considered. Participants experienced increases in both commission and omission errors for goal switching and response switching. A unique and short-lived effect in omission error was found for response switching, particularly when combined with stimulus repetition. The data are discussed in light of the measurement of vigilance decrement and whether breaks help or hinder sustained attention. Email: Ben Dyson,
[email protected]
(5115) Unconscious Processing of Pictures Revealed by Mouse Movement Trajectories. KUNCHEN XIAO and TAKASHI YAMAUCHI, Texas A&M University—Unconscious priming effects are often taken as the evidence for the idea that complex information can be processed unconsciously. However, it has been argued that the results based on reaction time measures can be contaminated by participants’ intentional control. To mitigate these problems, a priming framework was combined with a mouse movement method that measured trajectories of a cursor in a trial to reveal priming. Participants were instructed to judge, by clicking a button on the screen with a computer mouse, if two numbers (targets) were the same or not after briefly presented pictures (primes), while the mouse trajectory was recorded in each trial to assess priming effects. The movement data revealed larger deviation (measured by the area under a cursor trajectory) to an unselected choice in trials where the information about the priming pictures and numbers (targets) was conflicting, and an awareness test showed that such priming effect was still significant at a subliminal level. Taken together, results suggest that the
• CONSCIOUSNESS • (5113) The Effect of Mindfulness Meditation on Time Perception. ROBIN S.S. KRAMER, University of Kent, WEGER W. ULRICH, Universität Witten/Herdecke, DINKAR SHARMA, University of Kent—Research has increasingly focussed on the benefits of meditation in everyday life and performance. Mindfulness in particular improves attention, working memory capacity, and reading comprehension. Given its emphasis on moment-to-moment awareness, we hypothesised that mindfulness meditation would alter time perception. Using a within-subjects design, participants carried out a temporal bisection task, where several probe durations are compared to “short” and “long” standards. Following this, participants either listened to an audiobook or a meditation
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