Pseudoneglect for the bisection of mental number lines

Patients with unilateral neglect of the left side bisect physical lines to the right whereas individuals with an intact brain bisect lines slightly to the left (pseudoneglect). Similarly, for mental number lines, which are arranged in a left-to-right ascending sequence, neglect patients bisect to the right. This study determined whether individuals with an intact brain show pseudoneglect for mental number lines. In Experiment 1, participants were presented with visual number triplets (e.g., 16, 36, 55) and determined whether the numerical distance was greater on the left or right side of the inner number. Despite changing the spatial configuration of the stimuli, or their temporal order, the numerical length on the left was consistently overestimated. The fact that the bias was unaffected by physical stimulus changes demonstrates that the bias is based on a mental representation. The leftward bias was also observed for sets of negative numbers (Experiment 2)--demonstrating not only that the number line extends into negative space but also that the bias is not the result of an arithmetic distortion caused by logarithmic scaling. The leftward bias could be caused by a rounding-down effect. Using numbers that were prone to large or small rounding-down errors, Experiment 3 showed no effect of rounding down. The task demands were changed in Experiment 4 so that participants determined whether the inner number was the true arithmetic centre or not. Participants mistook inner numbers shifted to the left to be the true numerical centre--reflecting leftward overestimation. The task was applied to 3 patients with right parietal damage with severe, moderate, or no spatial neglect (Experiment 5). A rightward bias was observed, which depended on the severity of neglect symptoms. Together, the data demonstrate a reliable and robust leftward bias for mental number line bisection, which reverses in clinical neglect. The bias mirrors pseudoneglect for physical lines and most likely reflects an expansion of the space occupied by lower numbers on the left side of the line and a contraction of space for higher numbers located on the right.     

Now you see it; now you don't: inhibiting recall and recognition of scenes

Postevent misleading information can distort people's memories by altering and adding scenes. But can you also inhibit the retrieval of information from memory? In two studies we show that postevent information can make memory for a scene less accessible. In both studies participants first saw an event (e.g. a restaurant scene displayed in slides, or a drunk‐driving incident shown via a video clip). Later they were shown the same event without a critical scene and were told either to use this to generate a story (Experiment 1) or to imagine the event (Experiment 2). Finally they were tested. Relative to controls, this postevent omission led to fewer people reporting the critical scene in free recall and in recognition. Thus, we demonstrated that it may be possible to inhibit memories. This finding has important implications for eyewitness testimony and the recovered memory debate. Copyright © 2001 John Wiley & Sons, Ltd.     

When Dreams Become Reality

In three experiments, we found that after a subtle suggestion, subjects falsely recognized words from their own dreams and thought they had been presented during the waking state. The procedure used in these studies involved three phases. Subjects studied a list of words on Day 1. On Day 2, they received a false suggestion that some words from their previously reported dreams had been presented on the list. On Day 3, they tried to recall only what had occurred on the initial list. Subjects falsely recognized their dream words at a very high rate—sometimes as often as they accurately recognized true words. They reported that they genuinely “remembered” the dream words, as opposed to simply “knowing” that they had been previously presented. These findings, which suggest that dreams can sometimes be mistaken for reality, have significant implications for the practice of psychotherapy.     

Integration of Certainty,Severity, and Celerity Information in Judged Deterrence Value: urther Evidence and Methodological Equivalence1

The purposes of these studies were (a) to establish on a general basis whether 3 time-honored manipulable components of punishment combine additively, or multi-plicatively in determining the judged deterrence value of a sanction, and (b) to explore the equivalence in principle of two mutually exclusive experimental designs. Study 1 used a repeated measures design whereas main and interactive effects of certainty and severity were substantial and appeared to follow a multiplying rule, celerity effects were very small and local. Studies 2a and 3 used independent groups and established that the results of Study 1 were not merely an arbitrary product of the method. The discussion addresses the minimal effects of celerity, the interaction between certainty and severity, and the theoretical implications of choice of method.     

Solving the eyewitness problem

Faulty eyewitness testimony is a major source of wrongful convictions. Four solutions are examined to safeguard against mistaken testimony having undue impact: (1) to overturn any conviction based solely on the uncorroborated testimony of a single eyewitness, (2) to require that an attorney be present at any pretrial identification procedure, (3) to allow an expert to testify during the trial about factors of perception and memory that could affect a witness's accuracy, and (4) to have the judge deliver a cautionary instruction to the jury, admonishing them to carefully scrutinize eyewitness testimony, or to educate them about such testimony. Each alternative is discussed within the context of psychological research and legal cases.     

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.     

Teaching young children how to use a computer-based Teletype as a “desk calculator”

The first stage in the research reported here was to teach students the mechanics of how to use a computer-based Teletype as a “desk calculator” in the solution of arithmetic problems. In the second stage, we examined a specific use for the desk-calculator program: we presented a series of word problems to the students and analyzed the solutions of these problems to determine the variables related to problem difficulty.     

Trivial persuasion in the courtroom: the power of (a few) minor details

Investigated the influence of trivial testimonial detail on judgments of 424 undergraduates who served as mock jurors. Ss read a summary of a court case involving robbery and murder. In Experiment 1, detailed testimony influenced judgments of guilt, even when the detail was unrelated to the culprit. In Experiment 2, detailed testimony was especially powerful when an opposing witness testified that she could not remember the trivial details. Subsequent analyses suggest that the impact of detailed testimony on guilt judgments is mediated by inferences about the eyewitnesses. When eyewitnesses provided more detail, they were generally judged to be more credible, to have a better memory for the culprit's face and for details, and to have paid more attention to the culprit.