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Biomedical subjects

J J Freyd

Publications and source records attributed to J J Freyd.

9 recordsLinked to original sources

Representational momentum in memory for pitch.

When a visual pattern is displayed at successively different orientations such that a rotation or translation is implied, an observer's memory for the final position is displaced forward. This phenomenon of representational momentum shares some similarities with physical momentum. For instance, the amount of memory shift is proportional to the implied velocity of the inducing display; representational momentum is specifically proportional to the final, not the average, velocity; representational momentum follows a continuous stopping function for the first 250 ms or so of the retention interval. In a previous paper (Kelly & Freyd, 1987) we demonstrated a forward memory asymmetry using implied changes in pitch, for subjects without formal musical training. In the current paper we replicate our earlier finding and show that the forward memory asymmetry occurs for subjects with formal musical training as well (Experiment 1). We then show the structural similarity between representational momentum in memory for pitch with previous reports of parametric effects using visual stimuli. We report a velocity effect for auditory momentum (Experiment 2), we demonstrate specifically that the velocity effect depends on the implied acceleration (Experiment 3), and we show that the stopping function for auditory momentum is qualitatively the same as that for visual momentum (Experiment 4). We consider the implications of these results for theories of mental representation.

Adult

Mental extrapolation and cognitive penetrability: reply to Ranney and proposals for evaluative criteria.

We propose three criteria for establishing that mentally extrapolated motions are impenetrable with respect to one's knowledge, beliefs, or expectations about the nature of corresponding physical motions, and we review recent findings on mental extrapolation and representational momentum that appear to meet these criteria. We also respond to some arguments recently proposed by Ranney (1989) and Hubbard and Bharucha (1988) that representational momentum is cognitively penetrable. We conclude that mental extrapolations are governed to at least some extent by the inherent properties of the underlying internal mechanisms.

Attention

Representing statics as forces in equilibrium.

Resting objects can be described according to the physical forces operating on them, forces that are balanced in static scenes. We hypothesized that in a related way, the perception of static scenes and objects might involve a representation of underlying dynamics. In our first experiments, subjects were shown a picture of a plant resting upon a table or hanging from a hook, followed by a picture of the plant in the same position without the supporting table or hook. Subjects attempted to remember the position of the plant and were then shown a third display, in which the plant was in the same position or was slightly above or slightly below the original position. We found that subjects made more errors for test displays showing the plant slightly below, as compared with displays showing the plant slightly above, the original position. That is, memory for the position of the previously supported object was distorted in the direction consistent with what would happen if the plant was to lose its source of support in real life. This effect depends on the initial display of support; in Experiment 2 we found no memory asymmetry when the plant was initially displayed without support. We replicated the results of Experiments 1 and 2 with a new stimulus set and modified procedure in Experiment 3. In our fourth study we experimented with a slightly different stable situation: a spring with a box on top of it. We found that subjects misremembered the spring as either more compressed or less compressed as predicted by the implied dynamics of the display sequence. We discuss issues raised by our findings, including the possibility that the conscious experience of concreteness in static scenes stems from the representation of underlying forces.

Cognition

Perception of dynamic information in static handwritten forms.

Handwriting recognition presents a problem for most theories of letter perception. How do people accurately discriminate letters given the variability in handwritten forms? We propose that perceivers detect and capitalize on information relating to production inherent in the static trace of the handwritten letter. In an "implicit detection" task, subjects' ability to detect stroke direction in a series of handwritten characters was found to be influenced by the particular drawing method used to generate the stimuli. Similar results were obtained in an "explicit detection" task in which the subjects were asked to speculate on the drawing method used to generate the samples. Our findings suggest that perceivers are able to extract information relating to production from the static trace. We propose that they can then use this information in conjunction with their knowledge of a common production process, shared by both producers and perceivers, to aid character recognition.

Form Perception

Probing the time course of representational momentum.

Observers saw a rectangle at three orientations along a path of rotation. They attempted to remember the third orientation and were then tested with a fourth orientation that was either the same as, or slightly different from, the third. As in previous representational momentum studies we find that memory for position is distorted in the direction of the implied motion, in analogy to physical momentum. We now report that memory shift increases with retention interval for small intervals, as predicted by the analogy. However, instead of reaching some asymptotic value, the memory shift then decreases with retention interval. The resulting U-shaped curve may be considered the result of two competing effects: a positive memory shift attributable to representational momentum, which dominates at short intervals, and a negative shift attributable to memory averaging effects, which dominates at longer intervals. The memory averaging effect increases with retention interval and is strongest for faster presentation rates. For very short retention intervals the rate of increase in memory shift is proportional to the implied velocity of the inducing display, as predicted from the analogy to physical momentum.

Humans

Implied velocity and acceleration induce transformations of visual memory.

In this study, the phenomenon of representational momentum (Freyd & Finke, 1984) is investigated in cases where visual memories are distorted by implied motions of the elements of a pattern. Our theory predicts that these memory distortions should be sensitive not only to the direction of the implied motions but also to changes in the implied velocity. Subjects observed a sequence of dot-pattern displays that implied that the dots were moving at either a constant velocity or constant acceleration, but in separate directions. Discrimination functions for recognizing the final pattern in the sequence revealed that subjects' memories had shifted forward, corresponding to small continuations of the implied motions. The induced memory shifts increased in size as the implied velocity and acceleration of the dots increased, but were eliminated when the display sequence implied a deceleration of the dots to a final velocity of zero. These findings suggest that mentally extrapolated motion may have some of the same inertial properties as actual physical motion.

Acceleration

Transformations of visual memory induced by implied motions of pattern elements.

Four experiments measured distortions in short-term visual memory induced by displays depicting independent translations of the elements of a pattern. In each experiment, observers saw a sequence of 4 dot patterns and were instructed to remember the third pattern and to compare it with the fourth. The first three patterns depicted translations of the dots in consistent, but separate directions. Error rates and reaction times for rejecting the fourth pattern as different from the third were substantially higher when the dots in that pattern were displaced slightly forward, in the same directions as the implied motions, compared with when the dots were displaced in the opposite, backward directions. These effects showed little variation across interstimulus intervals ranging from 250 to 2,000 ms, and did not depend on whether the displays gave rise to visual apparent motion. However, they were eliminated when the dots in the fourth pattern were displaced by larger amounts in each direction, corresponding to the dot positions in the next and previous patterns in the same inducing sequence. These findings extend our initial report of the phenomenon of "representational momentum" (Freyd & Finke, 1984a), and help to rule out alternatives to the proposal that visual memories tend to undergo, at least to some extent, the transformations implied by a prior sequence of observed events.

Adolescent