Trajectory forms as information for visual event recognition: 3-D perspectives on path shape and speed profile

Trajectory forms in events consist of the path shape and the speed profile (Bingham, 1987, 1995). Wickelgren and Bingham (2004) showed that adults can use the speed profile as visual information to recognize events from different perspectives, despite perspective distortions and differences in optical components. We now investigate whether adults can use trajectory forms to recognize events when the forms are viewed from 3-D perspectives and the path shape and speed profile vary. In Experiment 1, we tested recognition of events that differ in path shape (with the speed profile held constant). In Experiment 2, we tested recognition of events in which speed profiles were mapped onto circular paths. In Experiment 3, as a strong test of sensitivity to trajectory forms, we tested simultaneous separate recognition of speed profile and path shape when both varied across events. In all three experiments, events were viewed from multiple 3-D perspectives. The results show that both the shape of the path and the speed profile provide information for visual event recognition. We found that adults exhibit constancy (or view invariance) in being able to use trajectory forms to identify the same events when viewed from different 3-D perspectives.     

Trajectory forms as a source of information about events

The ability to use trajectory forms as visual information about events was tested. A trajectory form is defined as the variation in velocity along a path of motion. In Experiment 1, we tested the ability to detect trajectory form differences between simulations of a freely swinging pendulum and a hand-moved pendulum. The trajectory form of the freely swinging pendulum was symmetric around the mid-point, whereas the hand moved was not. In Experiment 2, we isolated trajectory form information by varying the amplitudes of events while holding their periods constant. Straight path versions of the harmonic events from Experiment 1 were tested. In Experiment 3, we tested sensitivity to symmetrical peakening or flattening of trajectory forms. Participants detected small differences in all three experiments. In Experiment 4, we tested the ability to identify specific events based only on differences in trajectory forms. Participants were able to identify four different events. We investigated properties of trajectory forms that might potentially be detected and used as information, and we found that the curvature yielded good results.     

Perspective Effects on Recall in a Testimony Paradigm

The two present studies examined the influence of perspective instructions given during encoding and retrieval on the recall of a visual event. Participants viewed slides or a film depicting a day in the life of a man. Before viewing the to-be-remembered event, they were instructed to adopt the perspective of an alcoholic vs. an unemployed man vs. no perspective (Experiment 1), or of an unemployed man vs. no perspective (Experiment 2). Participants in the first study were interviewed twice, with the second recall being preceded by either a change perspective instruction or without any specific instruction. In the second study, participants were interviewed using either a cognitive interview (CI) or a CI without the change perspective instruction. Results showed that adopting a perspective during encoding impaired recall performance and failed to demonstrate a significant benefit of the change perspective instruction. The theoretical and practical implications of these results are discussed.     

Interpreting conjoined noun phrases and conjoined clauses: Collective versus distributive preferences

Two experiments are reported that show that introducing event participants in a conjoined noun phrase (NP) favours a single event (collective) interpretation, while introducing them in separate clauses favours a separate events (distributive) interpretation. In Experiment 1, acceptability judgements were speeded when the bias of a predicate toward separate events versus a single event matched the presumed bias of how the subjects' referents were introduced (as conjoined noun phrases or in conjoined clauses). In Experiment 2, reading of a phrase containing an anaphor following conjoined noun phrases was facilitated when the anaphor was they, relative to when it was neither/each of them; the opposite pattern was found when the anaphor followed conjoined clauses. We argue that comprehension was facilitated when the form of an anaphor was appropriate for how its antecedents were introduced. These results address the very general problem of how we individuate entities and events when presented with a complex situation and show that different linguistic forms can guide how we construe a situation. The results also indicate that there is no general penalty for introducing the entities or events separately-in distinct clauses as "split" antecedents.     

Eye Remember What Happened: Eye‐Closure Improves Recall of Events but not Face Recognition

Eye‐closure improves event recall. We investigated whether eye‐closure can also facilitate subsequent performance on lineup identification (Experiment 1) and face recognition tasks (Experiment 2). In Experiment 1, participants viewed a theft, recalled the event with eyes open or closed, mentally rehearsed the perpetrator's face with eyes open or closed, and viewed a target‐present or target‐absent lineup. Eye‐closure improved event recall, but did not significantly affect lineup identification accuracy. Experiment 2 employed a face recognition paradigm with high statistical power to permit detection of potentially small effects. Participants viewed 20 faces and were later asked to recognize the faces. Thirty seconds before the recognition task, participants either completed an unrelated distracter task (control condition), or were instructed to think about the face with their eyes open (rehearsal condition) or closed (eye‐closure condition). We found no differences between conditions in discrimination accuracy or response criterion. Potential explanations and practical implications are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Interpreting conjoined noun phrases and conjoined clauses: Collective versus distributive preferences

Two experiments are reported that show that introducing event participants in a conjoined noun phrase (NP) favours a single event (collective) interpretation, while introducing them in separate clauses favours a separate events (distributive) interpretation. In Experiment 1, acceptability judgements were speeded when the bias of a predicate toward separate events versus a single event matched the presumed bias of how the subjects' referents were introduced (as conjoined noun phrases or in conjoined clauses). In Experiment 2, reading of a phrase containing an anaphor following conjoined noun phrases was facilitated when the anaphor was they, relative to when it was neither/each of them; the opposite pattern was found when the anaphor followed conjoined clauses. We argue that comprehension was facilitated when the form of an anaphor was appropriate for how its antecedents were introduced. These results address the very general problem of how we individuate entities and events when presented with a complex situation and show that different linguistic forms can guide how we construe a situation. The results also indicate that there is no general penalty for introducing the entities or events separately—in distinct clauses as “split” antecedents.     

Biased retellings of events yield biased memories

When people retell events, they take different perspectives for different audiences and purposes. In four experiments, we examined the effects of this postevent reorganization of events on memory for the original events. In each experiment, participants read a story, wrote a biased letter about one of the story characters, and later remembered the original story. Participants' letters contained more story details and more elaborations relevant to the purpose of their retellings. More importantly, the letter perspective affected the amount of information recalled (Experiments 1, 3, and 4) and the direction of the errors in recall (Experiments 1 and 3) and recognition (Experiment 2). Selective rehearsal plays an important role in these bias effects: retelling involves selectively retrieving and using story information, with consequent differences in memory. However, biased memory occurred even when the biased letters contained little, if any, specific information (Experiment 4) or contained the same amount and kinds of story information as a neutral control condition (Experiment 3). Biased memory is a consequence of the reorganizing schema guiding the retelling perspective, in addition to the effects of rehearsing specific information in retelling.     

Learning scenes from multiple views: Novel views can be recognized more efficiently than learned views

In two experiments, participants were trained to recognize a playground scene from four vantage points and were subsequently asked to recognize the playground from a novel perspective between the four learned viewing perspectives, as well as from the trained perspectives. In both experiments, people recognized the novel view more efficiently than those that they had recently used in order to learn the scene. Additionally, in Experiment 2, participants who viewed a novel stimulus on their very first test trial correctly recognized it more quickly (and also tended to recognize it more accurately) than did participants whose first test trial was a familiar view of the scene. These findings call into question the idea that scenes are recognized by comparing them with single previous experiences, and support a growing body of literature on the existence of psychological mechanisms that combine spatial information from multiple views of a scene.     

Development of three-dimensional form perception

In three experiments with infants and one with adults we explored the generality, limitations, and informational bases of early form perception. In the infant studies we used a habituation-of-looking-time procedure and the method of Kellman (1984), in which responses to three-dimensional (3-D) form were isolated by habituating 16-week-old subjects to a single object in two different axes of rotation in depth, and testing afterward for dishabituation to the same object and to a different object in a novel axis of rotation. In Experiment 1, continuous optical transformations given by moving 16-week-old observers around a stationary 3-D object specified 3-D form to infants. In Experiment 2 we found no evidence of 3-D form perception from multiple, stationary, binocular views of objects by 16- and 24-week-olds. Experiment 3A indicated that perspective transformations of the bounding contours of an object, apart from surface information, can specify form at 16 weeks. Experiment 3B provided a methodological check, showing that adult subjects could neither perceive 3-D forms from the static views of the objects in Experiment 3A nor match views of either object across different rotations by proximal stimulus similarities. The results identify continuous perspective transformations, given by object or observer movement, as the informational bases of early 3-D form perception. Detecting form in stationary views appears to be a later developmental acquisition.     

Changing scenes: memory for naturalistic events following change blindness

Research on scene perception indicates that viewers often fail to detect large changes to scene regions when these changes occur during a visual disruption such as a saccade or a movie cut. In two experiments, we examined whether this relative inability to detect changes would produce systematic biases in event memory. In Experiment 1, participants decided whether two successively presented images were the same or different, followed by a memory task, in which they recalled the content of the viewed scene. In Experiment 2, participants viewed a short video, in which an actor carried out a series of daily activities, and central scenes' attributes were changed during a movie cut. A high degree of change blindness was observed in both experiments, and these effects were related to scene complexity (Experiment 1) and level of retrieval support (Experiment 2). Most important, participants reported the changed, rather than the initial, event attributes following a failure in change detection. These findings suggest that attentional limitations during encoding contribute to biases in episodic memory.     

Infant sensitivity to trajectory forms

The authors investigated whether infants are sensitive to visual event trajectory forms, and whether they are sensitive to the underlying dynamics of trajectory forms. The authors habituated 8-month-old infants to a videotaped event run either forward or reversed in time and then switched them to the same event run in the opposite direction. Infants dishabituated when switched to the event with the novel direction in time, indicating sensitivity to the form of the trajectory. Infants exhibited equivalent habituation rates and looking times for forward and reversed events, thus failing to provide evidence that infants are sensitive to the underlying dynamics. In a partial replication of this first experiment, the same pattern of results was found. Both experiments revealed infant sensitivity to the trajectory forms, but not the underlying dynamics of events. The authors discuss implications for methods used in infant event perception studies.     

Visual imagery in autobiographical memory: The role of repeated retrieval in shifting perspective

Recent memories are generally recalled from a first-person perspective whereas older memories are often recalled from a third-person perspective. We investigated how repeated retrieval affects the availability of visual information, and whether it could explain the observed shift in perspective with time. In Experiment 1, participants performed mini-events and nominated memories of recent autobiographical events in response to cue words. Next, they described their memory for each event and rated its phenomenological characteristics. Over the following three weeks, they repeatedly retrieved half of the mini-event and cue-word memories. No instructions were given about how to retrieve the memories. In Experiment 2, participants were asked to adopt either a first- or third-person perspective during retrieval. One month later, participants retrieved all of the memories and again provided phenomenology ratings. When first-person visual details from the event were repeatedly retrieved, this information was retained better and the shift in perspective was slowed.     

Imaging the future: Does a qualitative analysis add to the picture?

Various studies report that patients with dense amnesia experience difficulties in simulating future events. It is argued that this resembles an inability to remember past episodes in that both indicate a deficit in mental scene construction. Such findings, however, rely upon quantitative content-based analyses of participants' verbal reports. Here, samples of verbal reports produced by participants with hippocampal lesions are subjected to a qualitative, discourse analysis of how participants and researchers negotiated the status of these reports. This shows that failure in mental scene construction can be viewed as an interactional achievement rather than the mere reporting of mental events. A multidisciplinary perspective which combines qualitative analysis with other forms of analytic technique may explain subtle differences between participants with hippocampal lesions and control participants.     

Post‐event information presented in a question form eliminates the misinformation effect

This study investigated the influences of sentence surface forms on the misinformation effect. After viewing a film clip, participants received a post‐event narrative describing the events in the film. Critical sentences in the post‐event narrative, presented in either a statement or a question form, contained misinformation instead of questions with embedded false presuppositions; thus participants did not have to answer questions about the original event. During the final cued‐recall test, participants were informed that any relevant information presented in the post‐event narrative was not in the original event and that they should not report it. Consistent with previous findings, Experiment 1 demonstrated that post‐event information presented as an affirmative statement produced the misinformation effect. More importantly, post‐event information presented in a question form, regardless of whether it contained a misleading or studied item, increased the recall of correct information and reduced false recall. Experiment 2 replicated the main finding and ruled out an alternative explanation based on the salience of misleading items. Post‐event information presented in a question form created a condition similar to that which produces the testing effect.     

Detection of collision events on curved trajectories: optical information from invariant rate-of-bearing change

Previous research (Andersen & Kim, 2001) has shown that a linear trajectory collision event (i.e., a collision between a moving object and an observer) is specified by objects that expand and maintain a constant bearing (the object location remains constant in the visual field). In the present study, we examined the optical information for detecting a collision event when the trajectory was of constant curvature. Under these conditions, a collision event is specified by expansion of an object and a constant rate-of-bearing change. Three experiments were conducted in which trajectory curvature and display duration were varied while time to contact, speed, and initial image position of the collision objects were maintained. The results indicated that collision detection performance decreased with an increase in trajectory curvature and decreased with a decrease in display duration, especially for highly curved trajectories. In Experiment 3, we found that the presentation of a constant rate-of-bearing change in noncollision stimuli resulted in an increase in the false alarm rate. These results demonstrate that observers can detect collision events on curved trajectories and that observers utilize bearing change information.     

Field and observer modes of remembering

Abstract

Nigro and Neisser (1983) contrasted two ways of remembering personal experiences: the rememberer may ‘see’ the event from his or her perspective as in normal perception, or ‘see’ the self engaged in the event as an observer would. Several factors contribute to the determination of perspective, but Nigro and Neisser also reported that many subjects claimed they could change to another perspective at will. We sampled personal memories from several life periods and assessed ability to change the initially reported perspective. Changing was easier for recent or vividly recalled events, harder for older and less vividly recalled events. Memory perspectives may differ in other aspects than their imagery. A second study was conducted to determine whether affective experience is altered when perspectives are changed. The affect experienced decreased when shifting from a field to an observer perspective, but did not change with the converse shift. These studies provide further evidence that remembering is more than retrieval. The information that enters awareness is determined by the information sources in memory and the organisational scheme adopted for recollection.     

Remembering is in the details: effects of test-list context on memory for an event

We examined how recognition judgements for a set of event details are influenced by the relative difficulty of the other details included on the test. Participants viewed a crime event and then assigned remember/know judgements to details on a recognition test. In Experiment 1, details of medium difficulty were more likely to be classified as remembered when mixed with hard details rather than easy details. Similarly, in Experiment 2, medium details presented in blocked format were more likely to be classified as remembered when preceded by a block of hard details rather than a block of easy details.The test-list context thus appears to influence how participants define remembering. In Experiment 3, informing participants of the relative difficulty of the upcoming block of details eliminated the blocking effect. Implications for accounts of remember/know judgements and for conducting memory interviews are discussed.