Elizabeth F. Loftus

A spreading-activation theory of semantic processing.

This paper presents a spreading-acti vation theory of human semantic processing, which can be applied to a wide range of recent experimental results. The theory is based on Quillians theory of semantic memory search and semantic preparation, or priming. In conjunction with this, several of the miscondeptions concerning Qullians theory are discussed. A number of additional assumptions are proposed for his theory in order to apply it to recent experiments. The present paper shows how the extended theory can account for results of several production experiments by Loftus, Juola and Atkinsons multiple-category experiment, Conrads sentence-verification experiments, and several categorization experiments on the effect of semantic relatedness and typicality by Holyoak and Glass, Rips, Shoben, and Smith, and Rosch. The paper also provides a critique of the Smith, Shoben, and Rips model for categorization judgments. Some years ago, Quillian1 (1962, 1967) proposed a spreading-acti vation theory of human semantic processing that he tried to implement in computer simulations of memory search (Quillian, 1966) and comprehension (Quillian, 1969). The theory viewed memory search as activation spreading from two or more concept nodes in a semantic network until an intersection was found. The effects of preparation (or priming) in semantic memory were also explained in terms of spreading activation from the node of the primed concept. Rather than a theory to explain data, it was a theory designed to show how to build human semantic structure and processing into a computer.

Reconstruction of automobile destruction: An example of the interaction between language and memory

Two experiments are reported in which subjects viewed films of automobiled accidents and then answered questions about events occurring in the films. The question, “About how fast were the cars going when they smashed into each other?” elicited higher estimates of speed than questions which used the verbs collided, bumped, contacted , or hit in place of smashed . On a retest one week later, those subjects who received the verb smashed were more likely to say “yes” to the question, “Did you see any broken glass?”, even though broken glass was not present in the film. These results are consistent with the view that the questions asked subsequent to an event can cause a reconstruction in ones memory of that event.

Semantic Integration of Verbal Information Into a Visual Memory.

A total of 1,242 subjects, in five experiments plus a pilot study, saw a series of slides depicting a single auto-pedestrian accident. The purpose of these experiments was to investigate how information supplied after an event influences a witnesss memory for that event. Subjects were exposed to either consistent, misleading, or irrelevant information after the accident event. Misleading information produced less accurate responding on both a yes-no and a two-alternative forced-choice recognition test. Further, misleading information had a larger impact if introduced just prior to a final test rather than immediately after the initial event. The effects of misleading information cannot be accounted for by a simple demand-characteristics explanation. Overall, the results suggest that information to which a witness is exposed after an event, whether that information is consistent or misleading, is integrated into the witnesss memory of the event.

Leading questions and the eyewitness report

A total of 490 subjects, in four experiments, saw films of complex, fast-moving events, such as automobile accidents or classroom disruptions. The purpose of these experiments was to investigate how the wording of questions asked immediately after an event may influence responses to questions asked considerably later. It is shown that when the initial question contains either true presuppositions (e.g., it postulates the existence of an object that did exist in the scene) or false presuppositions (e.g.. postulates the existence of an object that did not exist), the likelihood is increased that subjects will later report having seen the presupposed object. The results suggest that questions asked immediately after an event can introduce new — not necessarily correct — information, which is then added to the memorial representation of the event, thereby causing its reconstruction or alteration. 1 Although current theories of memory are derived largely from experiments involving lists of words or sentences, many memories occurring in everyday life involve complex, largely visual, and often fast-moving events. Of course, we are rarely required to provide precise recall of such experiences — though as we age, we often volunteer them — but on occasion such recall is demanded, as when we have witnessed a crime or an accident. Our theories should he able to encompass such socially important forms of memory. It is clearly of concern to the law, to police and insurance investigators, and to others to know something about the completeness, accuracy, and malleability of such memories. 2 When one has witnessed an important event, one is sometimes asked a series of questions about it. Do these questions, if asked immediately after the event, influence the memory of it that then develops? This paper first summarizes research suggesting that the wording of such initial questions can have a substantial effect on the answers given, and then reports four new studies showing that the wording of these initial questions can also influence the answers to different questions asked at [begin page 561] some later time. The discussion of these findings develops the thesis that questions asked about an event shortly after it occurs may distort the witness’ memory for that event.

Imagination inflation: Imagining a childhood event inflates confidence that it occurred.

Counterfactual imaginings are known to have far-reaching implications. In the present experiment, we ask if imagining events from one’s past can affect memory for childhood events. We draw on the social psychology literature showing that imagining a future event increases the subjective likelihood that the event will occur. The concepts of cognitive availability and the source-monitoring framework provide reasons to expect that imagination may inflate confidence that a childhood event occurred. However, people routinely produce myriad counterfactual imaginings (i.e., daydreams and fantasies) but usually do not confuse them with past experiences. To determine the effects of imagining a childhood event, we pretested subjects on how confident they were that a number of childhood events had happened, asked them to imagine some of those events, and then gathered new confidence measures. For each of the target items, imagination inflated confidence that the event had occurred in childhood. We discuss implications for situations in which imagination is used as an aid in searching for presumably lost memories.

Some facts about “weapon focus”

Abstract“Weapon focus” refers to the concentration of acrime witnesss attention on a weapon, and the resultant reduction in ability to remember other details of the crime. We examined this phenomenon by presenting subject-witnesses with a series of slides depicting an event in a fast-food restaurant. Half of the subjects saw a customer point a gun at the cashier; the other half saw him hand the cashier a check. In Experiment 1, eye movements were recorded while subjects viewed the slides. Results showed that subjects made more eye fixations on the weapon than on the check, and fixations on the weapon were of a longer duration than fixations on the check. In Experiment 2, the memory of subjects in the weapon condition was poorer than the memory of subjects in the check condition: In Experiment 1 similar, though only marginally significant, performance effects were obtained. These results provide the first direct empirical support for weapon focus.

Remembering emotional events: The fate of detailed information

Abstract Previous research has shown that people remember details from emotional events differently than details from neutral events. However, past research suffers from inadequate equating of the details tested in the emotional and neutral events. In the current five experiments, involving a total of 397 subjects, we equated the to-be-remembered detail information. Subjects in these experiments were presented with a thematic series of slides in which the content of one critical slide in the middle of the series varied. When the critical slide was emotional (a woman injured near a bicycle), compared to neutral in nature (a woman riding a bicycle), subjects were better able to remember a central detail but less able to remember a peripheral detail. To determine whether the emotional event led to different performance simply because it was unusual, we included a third condition, in which subjects saw an “unusual” version of the event (a woman carrying a bicycle on her shoulder). Subjects in the unusual cond...

Misinformation and Memory: The Creation of New Memories

Misleading information presented after an event can lead people to erroneous reports of that misinformation. Different process histories can be responsible for the same erroneous report in different people. We argue that the relative proportion of times that the different process histories are responsible for erroneous reporting will depend on the conditions of acquisition, retention, and retrieval of information. Given the conditions typical of most misinformation experiments, it appears that misinformation acceptance plays a major role, memory impairment plays some role, and pure guessing plays little or no role. Moreover, we argue that misinformation acceptance has not received the appreciation that it deserves as a phenomenon worthy of our sustained investigation. It may not tell us anything about impairment of memories, but it does tell us something about the creation of new memories.

Since the eruption of Mt. St. Helens, has anyone beaten you up? Improving the accuracy of retrospective reports with landmark events

When people are questioned about past experiences, it is common for eventsto be reported as happening more recently than they actually did. One technique for reducing the instances of this “forward telescoping” is tested in the current research: It involves the provision of landmark events that can clearly mark the beginning of the reference period. Such atechnique was shown to reduce the telescoping problem in five experiments, involving 1, 694 subjects. The landmark event used in two of the studies was the first major eruption of Mt. St. Helens, and use of this event was shown to significantly reduce the incidence of forward telescoping of crime victimizations. Asking subjects to provide their own personal landmarks had similar beneficial effects. Finally, a more usual public landmark event, New Year’s day, substantially reduced forward telescoping. At least part, but not all, of the benefit of landmark events appears to be due to their being dated rather precisely.

The possible role of source misattributions in the creation of false beliefs among preschoolers.

In this article the authors examine one possible factor in the creation of false beliefs among preschool-aged children, namely, source misattributions. The authors present the results from an ongoing program of research which suggest that source misattributions could be a mechanism underlying childrens false beliefs about having experienced fictitious events. Findings from this program of research indicate that, although all children are susceptible to making source misattributions, very young children may be disproportionately vulnerable to these kinds of errors. This vulnerability leads younger preschoolers, on occasion, to claim that they remember actually experiencing events that they only thought about or were suggested by others. These results are discussed in the context of the ongoing debate over the veracity and durability of delayed reports of early memories, repressed memories, dissociative states, and the validity risks posed by therapeutic techniques that entail repeated visually guided imagery inductions.