Synchronising horizontal arm movement with transparent motion.
The relationship between perception and motor performance was studied in a situation that required perceptual processing of a complex motion stimulus in which a target signal had to be segmented, selected, and tracked. Participants were asked to move their arm in synchrony with one surface of a transparent motion display in which two surfaces moved horizontally back-and-forth over each other. The quality of tracking performance was measured as a function of bottom-up and top-down perceptual cues and their interplay. Target signal strength was manipulated by lowering the relative amount of signal dots constituting the target, i.e., the coherence level (100%-50%-30%-10%; the distractor surface was always 100% coherent). A colour cue that distinguished the target from the distractor surface was either available or absent. In the presence of a colour cue, participants experienced little or no difficulties at coherence levels of 50%-100% but when surface formation was complicated by lowering the coherence level, synchronisation consistency decreased. This corresponds with continuous attempts, successful and unsuccessful, to correct inaccurate synchronisation. In the absence of a colour cue, difficulties were frequently observed in all coherence conditions, but they differed depending on the coherence level. Overall, these results suggest that colour can serve as a strong top-down cue for proper target selection and tracking, provided that bottom-up motion signals are sufficiently strong.
Bleumers
Lizzy
L
Laboratory of Experimental Psychology, Department of Psychology, Faculty of Psychology and Educational Sciences, K.U. Leuven, Tiensestraat 102, B-3000 Leuven, Belgium. Lizzy.Bleumers@psy.kuleuven.be
Ceux
Tanja
T
Buekers
Martinus
M
Wagemans
Johan
J
D000328:Adult; D001132:Arm / Q000502:physiology*; D003463:Cues; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*