Are the neural and behavioural mechanisms underlying the tracking of another human's movement different from that of tracking the movement of a non-biological system? In an experiment by Kilner, Pauligan, Blakemore, (2003) an interference effect was found during the observation and tracking of incongruent biological movements (another human performing a different action), but not so with incongruent nonbiological movements (a robot performing a different action). They defined this interference effect as the degree of change in the movement trajectory of the observer due to observed movement. Recent studies have shown that interference of this kind was subject to both biological and non biological stimuli. However, the question of whether a similar interference effect is present during the observation of movements that possess the same invariant characteristics of human movement such as minimum jerk trajectories with bell-shaped velocity profiles but are not produced by a human (Flash & Hogan, 1985) has not been previously addressed. The present experiment asked eight participants to perform vertical and horizontal movements either congruently or incongruently to novel non-biological movement stimuli sets that resemble human movement (added invariant characteristics) ranging from point light displays to 3D virtual models of humans. This was followed by an interpersonal task while tracking the movements of a human experimenter. Results demonstrated that a congruency effect was observed where incongruent human movements exhibited the most interference. In other conditions, similar congruency effects were observed where the magnitude of the interference was dependent on the biological similarity of the stimuli to actual human movement. Also a main effect of "biologicalness" (Sinusoidal vs. Sinusoidal with noise vs. Minimum Jerk), type (3d human vs. Human) and a main interaction of type and congruency (3d human vs. Human) were observed. We argue that the central nervous system is highly attuned to biological characteristics at the most deep-rooted level. It seems that biological characteristics such as movement optimality leading to the abstract representation of human movement are tightly coupled as they elicit similar interference effects as tracking movements performed by a human.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/27840 |
| Date | January 2007 |
| Creators | Edjoc, Rojiemiahd |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 51 p. |
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