Suppressing unwanted memories: where there is a will,there is a way?

Research suggests that suppressing unwanted thoughts, generally, is an ineffective thought control strategy, because suppression attempts oftentimes fail, and, furthermore, result in a paradoxical increase of unwanted thoughts, later on. The present study sought to investigate whether manipulated expectations about suppression efficacy determine actual effects of suppression attempts. To test this hypothesis, participants listened to an audiotaped story, and were subsequently appointed to one of four conditions: a no-instruction-control (n = 20), suppression (n = 20), suppression-works (n = 20; participants were told that suppression generally is a fruitful strategy), or suppression-does-not-work (n = 25; participants were told that suppression primarily has paradoxical effects) condition. Two hours later, participants' memories of the story were tested, and several metamemory questions were answered. Induced expectations actually determined the perceived efficacy of suppression attempts, as well as thought frequency, although perceived or actual accuracy of recollections was not affected by the instructions.     

Capacity,strategies, and metamemory: tests of a three-factor model of memory development

Multiple measures of three of the factors (capacity, strategies, and metamemory) hypothesized to cause improvements in memory with age were obtained from 179 children in kindergarten to second grade (younger: ages 5-8) or third and fourth grade (older: ages 8-11) during nine sessions of testing. Confirmatory factor analysis was computed separately for each age group. Results suggested that the fit of the three-factor model was statistically significantly better than a one-factor, general memory model for both age groups. However, the fit indices were borderline, and there was not sufficient evidence for a metamemory factor for younger children. The factors that influence memory performance may differ with age.     

Recognition Memory for Faces: Reliability and Validity of the Warrington Recognition Memory Test (RMT) in a Neurological Sample

In response to critiques regarding the psychometric limitations of the Warrington Recognition Memory Test for faces (RMT-F), the current study was conducted to examine the test-retest reliability and validity of the measure in a neurological sample. Forty adult outpatients, ages 35–81, were administered the RMT-F as part of their diagnostic exam. A second evaluation was conducted after an average interval of 7 months (range = 2–20 months). Results yielded a Pearson reliability coefficient of 0.81 (p < .001), indicating a clinically satisfactory index of stability. Correlations with other measures were conducted to examine convergent and divergent validity. Results indicate that the facial component of the RMT has adequate reliability for patients with established neurological disease, shows moderate correlations with other measures of complex visuospatial function, and shows no significant correlation with measures of verbal reasoning, visual problem-solving, or verbal fluency. These findings provide additional support for the clinical efficacy of this instrument for use in a diverse neurological patient sample.     

An investigation of the interaction between cognitive style and context reinstatement on the memory performance of eyewitnesses

The power of context reinstatement to improve recall is well established, but the degree of effect obtained varies widely between studies. Exploring possible causes for this variation, this paper examines the relationship between cognitive style and the efficacy of context reinstatement in improving free and cued recall in an eyewitness paradigm. Experiment 1, using a live staged event and a 1 week delay, indicated a significant improvement in free recall with the reinstatement of context and, as expected, no such improvement in cued recall. However, analysis of the data according to field dependency, as measured by Witkin, Oltman, Raskin, and Karp's [A manual for the Embedded Figures Test (1971) Palo Alto, CA: Consulting Psychologists Press] Group Embedded Figures Test (GEFT) revealed that, in free recall, field dependent witnesses' scores improved significantly with context reinstatement, whilst the scores of field independent witnesses did not. In cued recall, however, the field independent witnesses scored significantly higher overall than field dependent witnesses. Experiment 2 sought replication of these findings again utilised the GEFT and the Riding [Cognitive Styles analysis (1991) Birmingham: Learning and Training Technology] Cognitive Styles Analysis (CSA). Analysis of the data according to the Wholist-Analytic (W-A) dimension of the CSA, indicated no interaction with either context reinstatement or memorial performance. However the GEFT analysis produced similar results to that obtained in Experiment 1. The meaning of the interaction between the GEFT and both free and cued recall, and the failure of the CSA to similarly interact are discussed, together with the implication of these findings for establishing the value of reinstating context for individual eyewitnesses.     

Individual differences in information order effects: The importance of right-hemisphere access in belief updating

The order in which information is received alters the evaluation of causal hypotheses. Specifically, research suggests that the last piece of information oftentimes has the greatest impact on the evaluation and that the difference in subjective value between two pieces of information is an important factor influencing the magnitude of this recency effect. The present paper extends this line of work by exploring individual differences in this phenomenon via one's degree of handedness. Two hundred and five participants were given two hypothetical scenarios and related causal hypotheses accompanied by two pieces of additional information and asked to revise their belief in each hypothesis as information accumulated. Results confirmed predictions that 1) inconsistent/mixed-handers (those who use their non-dominant hand for at least some activities) show a larger effect with two pieces of inconsistent weak or strong information, and 2) neither mixed-handers nor consistent/strong-handers (those who use their dominant hand for almost all activities) show an effect with strong and weak pieces of consistent information. Mixed-handers' susceptibility to persuasive arguments and Ramachandran’s (1995; Ramachandran and Blakeslee, 1998) belief-updating theory centered around communication between the two halves of the brain and functional access to the right hemisphere are used to account for these data.     

Knowing in advance: the impact of prior event information on memory and event knowledge

We examined the influence of newly acquired information on children's memory and general representation of a personally experienced event. Thirty-five children between the ages of 5 and 7 years participated in the novel event (Visiting the Pirate). The day before participating, children were: (1) provided with new information specific to the up-coming event; (2) engaged in a discussion generally related to the event topic based on existing knowledge; or (3) discussed an unrelated topic. Advance information specific to the event led to better recall and, in particular, to better integration of the experience into a general event representation both soon after the event and at a follow-up interview 4 months later, whereas general discussion of the topic without the event specific information neither enhanced memory reports nor facilitated the integration of event information. Providing information in advance can have significant effects on memory and knowledge acquisition although many variables, including those relating to the specific content of the information, will affect this relation.     

Counterfactual thinking and confidence in blackjack: A test of the counterfactual inflation hypothesis

This research tests the idea that repeatedly generating counterfactual thoughts in response to recurring events can lead to impairments in memory for actual outcomes (i.e., counterfactual inflation hypothesis). Participants (N = 56) played 40 games of blackjack and listed their thoughts after each win. They were instructed to list evaluative counterfactuals, reflective counterfactuals, or any thoughts that came to mind following each loss. Because reflective counterfactuals focus only on the alternatives to reality, and not in addition to reality (like evaluative counterfactuals), they were expected to lead to the greatest degree of overestimations of performance and confidence for future blackjack playing. The results confirmed this hypothesis, and also demonstrated that the relationship between thought-listing instructions and confidence for the future was mediated by overestimations of performance. Thus, repeatedly generating reflective counterfactual thoughts appears to lead to a special case of imagination inflation with dysfunctional implications for future confidence and risk-taking.     

Global Model Analysis of Cognitive Variability

Residual fluctuations produced in typical experimental methodologies are examined as correlated noises. The effective range of the correlations was assessed by determining whether the decay over look-back time is better described as a power law or exponential. Both of these decay laws contain free parameters and it is argued that it is not possible to distinguish their models on the basis of simple measures of goodness-of-fit. Global analyses that evaluate models on the basis of how well they generalize are conducted. The models are examined in terms of three constructs that all bear on generalization: cross-validity, flexibility, and representativeness. Quantitative assessment of a large ensemble of data suggests that the correlations decay over time as a power law. The conclusion is that human residual fluctuation is a correlated fractal.     

Specialization effect and its influence on memory and problem solving in expert chess players

Expert chess players, specialized in different openings, recalled positions and solved problems within and outside their area of specialization. While their general expertise was at a similar level, players performed better with stimuli from their area of specialization. The effect of specialization on both recall and problem solving was strong enough to override general expertise—players remembering positions and solving problems from their area of specialization performed at around the level of players 1 standard deviation (SD) above them in general skill. Their problem-solving strategy also changed depending on whether the problem was within their area of specialization. When it was, they searched more in depth and less in breadth; with problems outside their area of specialization, the reverse. The knowledge that comes from familiarity with a problem area is more important than general purpose strategies in determining how an expert will tackle it. These results demonstrate the link in experts between problem solving and memory of specific experiences and indicate that the search for context-independent general purpose problem-solving strategies to teach to future experts is unlikely to be successful.     

A model of working memory capacity in the radial-arm maze task

The radial arm maze is one of the most commonly used tests for assessing working memory in laboratory animals. However, to date, there exists no quantitative method of estimating working memory capacity from performance on this task. Here, we present a mathematical model of performance on the radial arm maze from which we can derive estimates of capacity. We derive explicit results for the two most commonly used measures of performance as functions of number of arms in the maze and memory capacity, assuming a uniform random search. We simulate random non-uniform search strategies. Comparing our model to previous experiments, we show that our model predicts a working memory capacity in the range of 3-9 at the level of performance observed in these experiments. This estimate is within the typical estimate of human working memory capacity. Performance of rats on large mazes (e.g. 48 arms) has been used as evidence that the working memory capacity of rats may be significantly larger than that of humans. We report that memory capacity in the range 3-9 is sufficient to explain the performance of rats in very large radial mazes. Furthermore, when we simulate non-uniform random search strategies observed in the experiments, the resulting estimates do not differ significantly from those assuming a uniform random search. We conclude that a list-based model of working memory with modest capacity is more powerful than previously expected.