Jennifer J. Freyd

Apparent Motion of the Human Body

Observers viewed pairs of alternating photographs of a human body in different positions. Shortest-path motion solutions were pitted against anatomically possible movements. With short stimulus onset asynchronies (SOAs), observers tended to report the shortest path despite violations of anatomical constraints. However, with longer SOAs observers became increasingly likely to report the anatomically possible, but longer, paths. This finding, in conjunction with those from a second study, challenges the accepted wisdom that apparent motion paths are independent of the object. Instead, our findings suggest that when given enough time and appropriate stimuli, the visual system prefers at least some object-appropriate apparent motion paths.

The mental representation of movement when static stimuli are viewed

If the representation of movement is a fundamental organizing principle of cognition, as hypothesized here, it should be possible to find cases in which static stimuli induce a dynamic mental representation. Subjects viewed frozen-action photographs, and their memory for these scenes was tested. They found it harder to reject distractors when the distractors were photographs of the same scene shot later in time than when the distractors were photographs shot earlier in time. In a second study, an asymmetry in goodness of apparent motion was found between forward and backward action sequences. Both results support the hypothesis that people represent the motion implicit in a photograph.

A velocity effect for representational momentum

Observers were shown a rectangle at three orientations along a possible path of rotation. They were instructed to remember the third orientation in the sequence and then were presented with a rectangle at a fourth orientation that was either the same as, or slightly different from, the third orientation. Each observer tested was more likely to accept as “same” those distractors that were rotated slightly past the third orientation than those test items presented in the physically same position, and the degree of memory shift increased with increasing rate of presentation of the inducing displays.

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.

Timing and Apparent Motion Path Choice With Human Body Photographs

In demonstrations of apparent motion, observers typically report seeing motion along the shortest possible path between two sequentially presented objects. Recent work has demonstrated that violations of this shortest path rule occur with realistic photographs of a human body displayed for sufficiently long temporal intervals when a longer path is more anatomically plausible than the shortest path. The current set of experiments investigated the mechanisms by which information about biomechanical motion constrains apparent motion perception. In Experiment I, we demonstrated, first, that the availability of extra processing time does not simply—in and of itself—result in the perception of longer paths of apparent motion. Second, we rejected the hypothesis that the perception of biomechanically correct paths of apparent motion depends on biologically appropriate velocities. In Experiment 2, we discovered that the longer the motion path required to satisfy the biomechanical movement limitations of the stimulus, the longer the time needed to construct and therefore perceive that path. These findings together suggest that additional processing time is necessary, but not sufficient, for interpolations of longer paths.

Dissociative Tendencies, Attention, and Memory

Two groups of college students were selected on the basis of their scores on the Dissociative Experiences Scale (DES). The high-DES group (score > 20, M = 29.6; n = 54) and low-DES group (score < 10, M = 5.1; n = 54) both completed the standard and a new dualtask version of the Stroop ink-naming task with xs (baseline condition) and color, neutral, and emotionally charged words. Free recall results indicated that high-DES participants remembered fewer emotionally charged words than low-DES participants. We found a crossover interaction for Stroop interference: High-DES participants showed more interference (conflicting color – baseline latency for ink naming) in a selective-attention Stroop task and less interference in the dualtask Stroop task. The interaction between attentional context and dissociation for Stroop interference and the free recall results are consistent with a cognitive-environments view of dissociative tendencies. In this view, dissociative tendencies, which have been otherwise speculated to be largely deleterious, can be advantageous in certain contexts.

Shareability: The Social Psychology of Epistemology*

Psychologists and cognitive scientists interested in the nature of internal representations of human knowledge often use observable regularities or structures to infer what the innate constraints on those representations must be like. It is possible, however, that certain structures might come about only when a group of people share a knowledge domain. Furthermore, it is possible that there are analyzable constraints on knowledge structures that emerge when knowledge is being shared. Such constraints are referred to in this paper as “shareability” constraints. A number of examples of observable structures in human knowledge are discussed in terms of shareability constraints. An attempt is made to determine which sorts of structures are most shareable, and how those structures may differ from the sorts of structures that are easily represented by the individual mind but not easily shared between minds.

Forgetting Trauma Stimuli

Previous work reported in this journal suggested that the cognitive capacities of high dissociators are impaired under conditions of focused (selective) attention, but not under conditions of divided attention, compared with the cognitive capacities of low dissociators. Using a directed-forgetting paradigm, the current study demonstrated that under divided-attention demands, high dissociators have impaired memory for words associated with trauma (e.g., incest) but not for neutral words, as compared with low dissociators. In addition, high dissociators reported significantly more trauma history and significantly more betrayal trauma (abuse by a caregiver) than low dissociators. These results are consistent with the proposal that dissociation may aid individuals with histories of betrayal traumas to keep threatening information out of awareness.

Self-Reported Memory for Abuse Depends Upon Victim-Perpetrator Relationship

Abstract We present preliminary results from the Betrayal Trauma Inventory (BTI) testing predictions from betrayal trauma theory (Freyd. 1994, 1996, in press) about the relationship between amnesia and betrayal by a caregiver. The ??? assesses trauma history using behaviorally defined events in the domains of sexual, physical, and emotional childhood abuse, as well as other lifetime traumatic events. When participants endorse an abuse experience, follow-up questions assess a variety of factors including memory impairment and perpetrator relationship. Preliminary results support our prediction that abuse perpetrated by a caregiver is related to less persistent memories of abuse. This relationship is significant for sexual and physical abuse. Regression analyses revealed that age was not a significant predictor of memory impairment and that duration of abuse could not account for the findings.

Betrayal Trauma: Relationship to Physical Health, Psychological Distress, and a Written Disclosure Intervention

ABSTRACT In the current study we sought, first, to distinguish associations with health arising from types of trauma as indicated by betrayal trauma theory (Freyd, 1996, 2001), and, second, to investigate the impact of disclosing a trauma history in survey form and/or writing essays about betrayal traumas. We recruited 99 community adults reporting at least 12 months of chronic medical illness or pain, 80 of whom completed all four sessions of this six-month longitudinal intervention study. Participants were randomly assigned to write about betrayal traumas or neutral events, and they were randomly assigned to complete an extensive trauma survey or a long personality inventory, producing four groups of participants. All 99 participants were assessed at their initial visit for trauma history using the Brief Betrayal Trauma Survey (BBTS) and physical and mental symptoms. The BBTS assesses exposure to both traumas high in betrayal (such as abuse by a close other) and traumas low in betrayal but high in life-threat (such as an automobile accident). Exposure to traumas with high betrayal was significantly correlated with number of physical illness, anxiety, dissociation, and depression symptoms. Amount of exposure to other types of traumas (low betrayal traumas) did not predict symptoms over and above exposure to betrayal trauma. While neither the survey manipulation nor the writing intervention led to main effects on change in symptoms over time, there were interactions between betrayal trauma history and condition such that participants with many betrayal traumas fared better in the control conditions while participants with fewer betrayal traumas had better outcomes if they were placed in the trauma writing and/or survey conditions. We discuss ongoing and future research aimed at evaluating the role of increased structure in writing assignments as beneficial for those with severe histories of betrayal trauma.