Gezinus Wolters - Profile on Academia.edu (original) (raw)

Papers by Gezinus Wolters

Accuracy, confidence and consistency in repeated recall of events

Psychology Crime & Law, Aug 1, 2013

In legal practice, both confidence and consistency of the testimony of eyewitnesses are often use... more In legal practice, both confidence and consistency of the testimony of eyewitnesses are often used as indicators for accuracy, but their usefulness has been questioned. The present study was designed to determine the relationship between accuracy, confidence and consistency in episodic memory. After viewing a video of a complex series of events, one group of participants was given an initial

Accuracy and confidence of episodic memories of eyewitnesses

Acta Psychologica, Oct 1, 1982

The research reported here, explored the conditions where processing time can be used as a predic... more The research reported here, explored the conditions where processing time can be used as a predictive measure for retention performance. The results showed that, in similar but quantitatively different tasks, both processing time and retention performance increased with increasing task difficulty. This strongly suggests that processing time can be used as an independent measure for extensiveness of processing, and as a predictor for later retention performance. This relationship, however, is restricted to the comparison of similar processing tasks that differ only in the amount of processing necessary to perform the task. It is hypothesized that longer processing times are indicative of more extensive processing, leading to the formation of more distinctive memory representations. These, in turn, cause higher retention performance because they allow better discrimination from other memory traces, and because they are retrieved more easily. Although distinctiveness of memory representations is an important variable in determining retention performance, it is not the only one. In a recall test, semantic relations between items had an effect on performance independent of distinctiveness.

Ó Marta Olivetti Belardinelli and Springer-Verlag 2007

executive’, is used to guide behavior by internal goals or intentions. We suggest that WM is best... more executive’, is used to guide behavior by internal goals or intentions. We suggest that WM is best described as a set of three interdependent functions which are implemented in the prefrontal cortex (PFC). These functions are maintenance, control of attention and integration. A model for the maintenance function is presented, and we will argue that this model can be extended to incorporate the other functions as well. Maintenance is the capacity to briefly maintain information in the absence of corresponding input, and even in the face of distracting information. We will argue that maintenance is based on recurrent loops between PFC and posterior parts of the brain, and probably within PFC as well. In these loops information can be held temporarily in an active form. We show that a model based on these structural ideas is capable of maintaining a limited number of neural patterns. Not the size, but the coherence of patterns (i.e., a chunking principle based on synchronous firing of i...

Voluntary and automatic attention in visual and auditory perception

Bulletin of the Psychonomic Society, 1992

Beneficial effects oflocation cuing in single-letter recognition tasks have been found in a numbe... more Beneficial effects oflocation cuing in single-letter recognition tasks have been found in a number of studies. Van der Heijden, Neerincx, and Wolters (1989) have argued that such identity benefits can be expressed as a fraction of the room for improvement in position information. Their model suggests that an attentional process may, through the addition of location information, enhance identification performance. For this model to be correct, however, two conditions must be met: (1) position information of the target letters has to be missing in a proportion of the trials, and (2) identity benefits have to be smaller than the room for improvement in position information. Two experiments are reported in which position and identity information of single target letters are determined under identical conditions. The outcomes of both experiments are consistent with the conditions suggested by the model. Demonstrating positive selective attention effects on recognition accuracy with single-item displays has proved very hard. Grindley and Townsend (1968) tried but failed. In subsequent location-cuing experiments, attentional benefits were demonstrated, but the effects were generally very small (from 2 % to 5 %;

Enhancing Single-Item Recognition Accuracy by Cueing Spatial Locations in Vision

The Quarterly Journal of Experimental Psychology Section A, 1985

With single-item visual displays, facilitating effects of foreknowledge of position have been sho... more With single-item visual displays, facilitating effects of foreknowledge of position have been shown in detection tasks with latency and with accuracy as the dependent variables, as well as in recognition tasks with latency as the dependent variable. There is no evidence, however, of positive selective attention effects on recognition accuracy with single-item displays. One failure to find such an effect was reported by Grindley and Townsend (1968). It is argued that in the study of Grindley and Townsend sub-optimal conditions were used and that a more elaborate replication of their study is in order. In the experiment reported here, an exposure duration resulting in 75% correct recognitions of target letters was determined per subject. This exposure time was used in the subsequent experimental sessions. In the experimental trials, single letters were presented on one out of five positions on an imaginary circle around a fixation point. The position of the impending target item was e...

A neurophysiological account of working memory limited capacity: Within-chunk integration and betweenitem segregation

Mental arithmetic: Effects of calculation procedure and problem difficulty on solution latency

Journal of Experimental Child Psychology, 1990

In this chronometric study of mental arithmetic, problems with sums greater than 20 and less than... more In this chronometric study of mental arithmetic, problems with sums greater than 20 and less than 100 were presented to third-grade subjects (age 8-9). It is argued that such problems are calculated by using procedures in which the problem is broken down into subproblems for which solutions are retrieved from a declarative knowledge base. Important bottlenecks in this process are the processing capacity (since only one subproblem can be handled at a time) and the storage capacity of working memory (since the original problem and all outcomes of subproblems have to be retained). Therefore it can be hypothesized that arithmetic procedures and types of problems that necessitate more subproblems will lead to longer solution times. Both hypotheses were confirmed. Significant interactions between types of problems and arithmetic procedures show an increasing difference in solution time between the procedures with increasing problem difficulty. It can be concluded that for the type of problems studied, arithmetic procedures requiring a smaller number of subproblems lead to better performance.

De relatie tussen accuratesse en subjectieve zekerheid van episodische herinneringen van getuigen

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Bulletin of the Psychonomic Society, 1989

In studies that clearly show that location cuing benefits in single-item recognition tasks are a ... more In studies that clearly show that location cuing benefits in single-item recognition tasks are a linear function of the room for improvement, researchers have varied room for improvement by manipulating the distance of targets to the fixation point. To show that such benefits are not the result of probing different parts ofthe retina, we manipulated room for improvement in this study by varying the presentation time oftargets. The same relationship between locat ion cuing benefits and room for improvement was found. Therefore, it is parsimonious to conclude that it is indeed room for improvement, and not retinal position or exposure duration, that determines the size of the cuing effect. A tentative model for explaining location cuing benefits is presented. The model shows that an un interpretable empirical relationship can be rewritten into a theoretically interpretable form.

BJA: British Journal of Anaesthesia, 1987

UNCONSCIOUS PERCEPTION DURING GENERAL ANAESTHESIA Sir,-Whether a patient can store memories durin... more UNCONSCIOUS PERCEPTION DURING GENERAL ANAESTHESIA Sir,-Whether a patient can store memories during anaesthesia is fundamentally important to our conception of what is anaesthesia. It is, therefore, regrettable that publications that make startling claims do not provide adequate evidence because of statistical and methodological shortcomings. Bonke and colleagues (1986) believe that positive auditory suggestions during an operation can lead to a shorter postoperative stay in hospital in older patients. It is, however, not particularly surprising that they have found one "significant" comparison, since they have carried out 14 separate statistical tests on the outcome data. A rough rule in this situation is to multiply the obtained P value by the number of tests, and this would produce a corrected P value of 0.004 x 14 = 0.056 which is not so impressive, especially since the groups were unbalanced in age. Further manipulation by pooling two of the groups and then splitting by age on the basis of observed results invalidates any resulting P values. Indeed, as duration of stay is likely to be affected by so many extraneous factors, common sense suggests that this would be the least likely outcome to show an effect of suggestion. It is unfortunate that the most informative result-overall effect of treatments corrected for age-was not provided. Bennett, Davis and Giannini (1985) stated that their "data. ..establish the phenomenon of a non-verbal response to intra-operative conversation"; that is to say, these patients could be persuaded later to touch an ear more frequently than the control patients. However, when the number of patients in each group who touched an ear at least once during interview are compared, using the correctly calculated and more appropriate tzoo-sided Fisher's Exact Probability Test, P •= 0.08. Furthermore, the tetrachoric correlation does not only seem inappropriate for such discrete data, but the correctly calculated value is 0.05 in place of the claimed P < 0.001. Finally, although there were more ear pulls per postoperative interview per patient in the suggestion group than in the control group (Mann-Whitney U test, P > 0.02), no preoperative record was made of the frequency of ear pulls in each group to show that they were initially similar in this respect. Perhaps the most dramatic claim was made by Levinson (1965) some years ago, that four out of 10 subjects could, when later hypnotized, recall a simulated emergency enacted during deep ether anaesthesia. Unfortunately, there were no control subjects in this study, the hypnotist knew the nature of the "emergency" and insufficient details were published of the interview between the hypnotist and the subject to enable one to judge if leading questions were asked and to judge how accurately the subjects recalled the stimulus words. Despite allusions to further work, a more detailed study was never forthcoming. It is our contention that these three papers, which might be considered to be key ones, do not provide adequate evidence. A more rigorous, critical review of methodology is called for when novel claims are made that have great theoretical or practical implications.

Handbook of Binding and MemoryPerspectives from Cognitive Neuroscience, 2006

Models of long-term and working memory assume various forms of binding processes. Long-term memor... more Models of long-term and working memory assume various forms of binding processes. Long-term memory consolidation involves a process whereby memory representations are first bound by the hippocampus and certain surrounding areas. Then, a consolidation process is assumed whereby the binding role is transferred from the hippocampus to neocortical sites, a movement from hippocampal-cortical to cortico-cortical connectivity. Many models of working memory assume that high levels of neural synchrony or simultaneous firing rate represent its memory contents. Short-term binding is thus accomplished through firing rates and temporal correlations of firing that emerge from the complex interplay of existing connections and from the effects of the recent activation history (from 'thinking', planning, perception, setting of motor movements, etc.). In a few seconds this content can in principle be transferred to long-term memory, specifically to the hippocampus, via Hebbian plasticity. In this paper, we will present a binding perspective from two connectionist models developed by us: a model of binding in working memory and a model of trace binding in long-term memory consolidation. We will delineate four different neurodynamical binding mechanisms, describe and discuss these two models of short-term and long-term memory binding, and finally present ideas for an integrated model architecture of binding in memory.

Elaboration effects in implicit and explicit memory tests

Psychological Research, 1996

Abstract Dissociation effects in explicit and implicit tests of memory were examined in two exper... more Abstract Dissociation effects in explicit and implicit tests of memory were examined in two experiments. In Experiment 1 serial-position effects were studied. Re-sults showed that the standard primacy effect found in free recall is absent in an implicit word-stem comple-tion test. In ...

A constructivist and connectionist view on conscious and nonconscious processes

Philosophical Psychology, 1997

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Contrasts and dissociations suggest qualitative differences between conscious and unconscious processes

Behavioral and Brain Sciences, 2002

The authors reject a computationally powerful unconscious. Instead, they suggest that simple unco... more The authors reject a computationally powerful unconscious. Instead, they suggest that simple unconscious processes give rise to complex conscious representations. We discuss evidence showing contrastive effects of conscious and unconscious processes, suggesting a distinction between these types of processes. In our view, conscious processes often serve to correct or control negative consequences of relatively simple unconscious processes.

A competitive manifesto

Behavioral and Brain Sciences, 2000

The distinction made by Page between localist and distributed representations seems confounded by... more The distinction made by Page between localist and distributed representations seems confounded by the distinction between competitive and associative learning. His manifesto can also be read as a plea for competitive learning. The power of competitive models can even be extended further, by simulating similarity effects in forced-choice perceptual identification (Ratcliff & McKoon 1997) that have defied explanation by most memory models.

The American Journal of Psychology, 1986

Renal dysfunction is a common comorbidity in patients with liver failure and is a well-establishe... more Renal dysfunction is a common comorbidity in patients with liver failure and is a well-established predictor of both morbidity and mortality among patients awaiting liver transplantation. The etiology of renal failure in patients with cirrhosis can be functional, structural, or represent a combination of potentially reversible physiologic changes and permanent histologic damage. Diagnostic criteria for acute and chronic kidney disease have been established, but cirrhosis poses challenges for accurate assessment of renal function with conventional clinical methods such as serum creatinine and creatinine-based estimating equations. Renal biopsies can have an important role for defining permanent structural damage as part of the pre-transplant evaluation of patients with liver disease; however, coagulopathy, portal hypertension and ascites increase the risk of biopsy-associated complications in cirrhotic patients. While renal dysfunction due to hepatorenal physiology is potentially reversible after liver transplantation, simultaneous kidney liver transplantation and kidney after liver transplant can also improve outcomes in a subset of patients with irreversible renal injury.

Attentional Shifts in Maintenance Rehearsal

The American Journal of Psychology, 1993

The distinction between maintenance and elaborative rehearsal was inves-tigated in four experimen... more The distinction between maintenance and elaborative rehearsal was inves-tigated in four experiments. Experiments 1-3 showed that long periods of maintenance rehearsal, induced in a distractor recall procedure, consistently produced small increases in recall ...