Susan E. Ruppel

Representational Momentum and Michotte's (1946/1963) "Launching Effect" Paradigm

In A. Michottes (1946/1963) launching effect, a moving launcher contacts a stationary target, and then the launcher becomes stationary and the target begins to move. In this experiment, observers viewed modifications of a launching effect display, and displacement in memory for the location of targets was measured. Forward displacement of targets in launching effect displays was decreased relative to that of targets (a) that were presented in isolation and either moved at a constant fast or slow velocity or decelerated or (b) that moved in a direction orthogonal to previous motion of the launcher. Possible explanations involving a deceleration of motion or landmark attraction effects were ruled out. Displacement patterns were consistent with naive impetus theory and the hypothesis that observers believed impetus from the launcher was imparted to the target and then dissipated.

A possible role of naïve impetus in Michotte's "launching effect": Evidence from representational momentum

In Michottes (1946/1963) launching effect paradigm, a moving launcher contacts a stationary target, and then the launcher becomes stationary and the target begins to move. In the experiments reported here, observers were presented with modifications of a launching effect display, and displacement in memory for targets was measured. Faster launcher velocities resulted in larger displacements for moving targets, and the effect of launcher velocity was larger with faster target velocities. Launcher velocity did not influence displacement of targets that remained stationary after contact. Increases in the distance travelled by moving targets after contact from the launcher resulted in smaller displacements. Displacement appeared to result from an expectation that impetus would be imparted from the launcher rather than from contact between the launcher and the target. Displacement patterns were consistent with naïve impetus theory and with the hypothesis that observers believed impetus from the launcher was imparted to the target and dissipated with subsequent target motion.

Representational momentum is not (totally) impervious to error feedback.

The influence of feedback on representational momentum for the final location of a moving target was examined in 3 experiments. The presence of binary feedback (correct, error) during practise trials or during larger blocks of experimental trials did not reduce representational momentum, nor did the presence of more informative feedback specifying the direction of error (error-in front of, error-behind) during larger blocks of experimental trials reduce representational momentum. Effects on representational momentum of whether feedback was consistently provided were inconsistent. Even though feedback did not reduce representational momentum per se, feedback did influence the probability of a same response for different probe positions. Implications of the data for R. A. Finke and J. J. Freyds (1985; J. J. Freyd, 1987) claim that representational momentum is impervious to error feedback, and possible roles of perceptual learning in representational momentum, are discussed.

Ratings of causality and force in launching and shattering

Ratings of perceived force and ratings of perceived causality were obtained for stimuli in which an initially moving object contacted an initially stationary object, and upon contact (1) the initially moving object became stationary or shattered into four or nine fragments and (2) the initially stationary object remained stationary, was launched into motion, or shattered into four or nine fragments. Implied motion rather than smooth or continuous motion was presented. The initially moving object was rated as more causal and as exerting more force if upon contact the initially stationary object was launched into motion or shattered, but the initially stationary object was rated as more causal and as exerting more force if upon contact the initially moving object stopped or shattered (and the initially stationary object remained stationary and intact). An object that did not shatter or that shattered into fewer fragments was rated as more causal and as exerting more force than an object that shattered into more fragments. If the initially moving object stopped upon contact and the initially stationary object remained stationary, the initially stationary object was rated as more causal. The results are not consistent with theories of phenomenal causality that suggest (1) moving objects are always perceived as more causal and as exerting more force than stationary objects and (2) perception of causality is identical to perception of force.

Effects of temporal and spatial separation on velocity and strength of illusory line motion

The effects of line length and of spatial or temporal distance on illusory line motion (i.e., on the perception that a stationary line unfolds or expands away from a previously presented stationary cue) were examined in five experiments. Ratings of relative velocity decreased with increases in stimulus onset asynchrony between appearance of the cue and appearance of the line (from 50 to 450xa0ms), whereas the extremity of ratings of direction (i.e., strength of the ratings of illusory line motion) increased with increases in stimulus onset asynchrony (from 50 to either 250 or 450xa0ms). Ratings of relative velocity increased with increases in line length, whereas ratings of direction were not influenced by increases in line length. Ratings of relative velocity and direction were not influenced by increases in the distance of the near or the far end of the line from the cue. Implications of these data for attentional theories and apparent-motion theories of illusory line motion are discussed.

A Fröhlich Effect and Representational Gravity in Memory for Auditory Pitch

Memory for the initial pitch of an auditory target that increased or decreased in auditory frequency was examined. Memory was displaced forward in the direction of pitch motion, and this is consistent with the Fröhlich effect previously observed for visual targets moving in visual physical space. The Fröhlich effect for pitch increased with faster target velocity and decreased if an auditory cue with the same pitch as the initial pitch of the target was presented before the target was presented. The Fröhlich effect was larger for descending pitch motion than for ascending pitch motion, and this is consistent with an influence of representational gravity. The data suggest that representation of auditory frequency space exhibits some of the same biases as representation of visual physical space, and implications for theories of attention in displacement and for crossmodal and multisensory representation of space are discussed.

Effects of spatial cuing on the onset repulsion effect

Effects of cuing the onset (initial) location of a moving target on memory for the onset location of that target were examined. If a cue presented prior to target onset indicated the location where that target would appear, the onset repulsion effect (in which the judged initial location of the target was displaced in the direction opposite to target motion) was decreased, and the onset repulsion effect was smaller if the cue was valid than if the cue was invalid. If a cue presented during target motion or after the target vanished indicated the location where that target had appeared, the onset repulsion effect was eliminated. The data (1) suggest that positional uncertainty might contribute to the onset repulsion effect, (2) provide the first evidence of an effect of expectancy regarding target trajectory on the onset repulsion effect, and (3) are partially consistent with previous data involving effects of attention and spatial cuing on the Fröhlich effect and on representational momentum.

An Effect of Contrast and Luminance on Visual Representational Momentum for Location

Effects of the contrast of target luminance and background luminance, and of the absolute level of target luminance, on representational momentum for the remembered final location of a previously viewed moving target were examined. Targets were high in contrast or luminance, decreasing in contrast or luminance, increasing in contrast or luminance, or low in contrast or luminance; the background was black or white. Representational momentum for target location was larger if targets were high or increasing in contrast or luminance and smaller if targets were low or decreasing in contrast or luminance. Representational momentum for target location was larger if targets were presented on a white background than on a black background. Implications for theories of localization and for theories of representational momentum are discussed.

Displacement of location in illusory line motion

Six experiments examined displacement in memory for the location of the line in illusory line motion (ILM; appearance or disappearance of a stationary cue is followed by appearance of a stationary line that is presented all at once, but the stationary line is perceived to “unfold” or “be drawn” from the end closest to the cue to the end most distant from the cue). If ILM was induced by having a single cue appear, then memory for the location of the line was displaced toward the cue, and displacement was larger if the line was closer to the cue. If ILM was induced by having one of two previously visible cues vanish, then memory for the location of the line was displaced away from the cue that vanished. In general, the magnitude of displacement increased and then decreased as retention interval increased from 50 to 250xa0ms and from 250 to 450xa0ms, respectively. Displacement of the line (a) is consistent with a combination of a spatial averaging of the locations of the cue and the line with a relatively weaker dynamic in the direction of illusory motion, (b) might be implemented in a spreading activation network similar to networks previously suggested to implement displacement resulting from implied or apparent motion, and (c) provides constraints and challenges for theories of ILM.

Perceived causality, force, and resistance in the absence of launching

In the launching effect, a moving object (the launcher) contacts a stationary object (the target), and upon contact, the launcher stops and the target begins moving in the same direction and at the same or slower velocity as previous launcher motion (Michotte, 1946/1963). In the study reported here, participants viewed a modified launching effect display in which the launcher stopped before or at the moment of contact and the target remained stationary. Participants rated perceived causality, perceived force, and perceived resistance of the launcher on the target or the target on the launcher. For launchers and for targets, increases in the size of the spatial gap between the final location of the launcher and the location of the target decreased ratings of perceived causality and ratings of perceived force and increased ratings of perceived resistance. Perceived causality, perceived force, and perceived resistance exhibited gradients or fields extending from the launcher and from the target and were not dependent upon contact of the launcher and target. Causal asymmetries and force asymmetries reported in previous studies did not occur, and this suggests that such asymmetries might be limited to typical launching effect stimuli. Deviations from Newton’s laws of motion are noted, and the existence of separate radii of action extending from the launcher and from the target is suggested.