Biomedical subjects

John T Wixted

Publications and source records attributed to John T Wixted.

14 recordsLinked to original sources

PubMed2007

Dual-process theory and signal-detection theory of recognition memory.

Two influential models of recognition memory, the unequal-variance signal-detection model and a dual-process threshold/detection model, accurately describe the receiver operating characteristic, but only the latter model can provide estimates of recollection and familiarity. Such estimates often accord with those provided by the remember-know procedure, and both methods are now widely used in the neuroscience literature to identify the brain correlates of recollection and familiarity. However, in recent years, a substantial literature has accumulated directly contrasting the signal-detection model against the threshold/detection model, and that literature is almost unanimous in its endorsement of signal-detection theory. A dual-process version of signal-detection theory implies that individual recognition decisions are not process pure, and it suggests new ways to investigate the brain correlates of recognition memory.

Humans↗

PubMed2006

The hippocampus supports both the recollection and the familiarity components of recognition memory.

The receiver operating characteristic (ROC) has been used to investigate the component processes of recognition memory. Some studies with this technique have been taken to indicate that the hippocampus selectively supports the process of recollection, whereas adjacent cortex in the parahippocampal gyrus supports the process of familiarity. We analyzed ROC data from young adults, memory-impaired patients with limited hippocampal lesions, and age-matched controls. The shape of the ROC changed in similar ways from asymmetric to symmetric, as a function of the strength of memory (strong to weak) in both the young adults and the patients. Moreover, once overall memory strength was similar, the shape of the patient ROC was asymmetric and matched the control ROC. These results suggest that the component processes that determine the shape of the ROC are operative in the absence of the hippocampus, and they argue against the idea that the hippocampus selectively supports the recollection process.

Adult↗

PubMed2006

Distributed practice in verbal recall tasks: A review and quantitative synthesis.

The authors performed a meta-analysis of the distributed practice effect to illuminate the effects of temporal variables that have been neglected in previous reviews. This review found 839 assessments of distributed practice in 317 experiments located in 184 articles. Effects of spacing (consecutive massed presentations vs. spaced learning episodes) and lag (less spaced vs. more spaced learning episodes) were examined, as were expanding interstudy interval (ISI) effects. Analyses suggest that ISI and retention interval operate jointly to affect final-test retention; specifically, the ISI producing maximal retention increased as retention interval increased. Areas needing future research and theoretical implications are discussed.

Humans↗

PubMed2006

Effect of delay on recognition decisions: evidence for a criterion shift.

Recent evidence indicates that in intermixed recognition testing of different stimulus classes, people can apply different decision criteria (a criterion shift) to stimulus classes distinguished by the study-test delay (Singer, Gagnon, & Richards, 2002), but not by a conspicuous strength manipulation (Stretch & Wixted, 1998b). In an attempt to reconcile these differences, we applied Singer et al.'s text retrieval method to word recognition. People first studied blocked items from each of five categories. After a delay, five new category lists were presented. After each one, the participants recognized intermixed targets and distractors from the current category and one of the earlier ones. At delays of up to 40 min, the answering criteria for immediate and delayed categories were indistinguishable. At delays of 2 days, in contrast, however, both yes-no and confidence-rating data indicated that more lenient criteria were applied to delayed than to immediate test items. This suggests that people can use the delay between study and test to flexibly adjust the decision criteria of word recognition.

Adolescent↗

PubMed2005

When does feedback facilitate learning of words?

Some researchers have suggested that although feedback may enhance performance during associative learning, it does so at the expense of later retention. To examine this issue, subjects (N = 258) learned Luganda-English word pairs. After 2 initial exposures to the materials, subjects were tested on each item several times, with the presence and type of feedback varying between subjects. A final test followed after 1 week. Supplying the correct answer after an incorrect response not only improved performance during the initial learning session--it also increased final retention by 494%. On the other hand, feedback after correct responses made little difference either immediately or at a delay, regardless of whether the subject was confident in the response. Practical and theoretical implications are discussed.

Feedback↗

PubMed2004

On Common Ground: Jost's (1897) law of forgetting and Ribot's (1881) law of retrograde amnesia.

T. Ribot's (1881) law of retrograde amnesia states that brain damage impairs recently formed memories to a greater extent than older memories, which is generally taken to imply that memories need time to consolidate. A. Jost's (1897) law of forgetting states that if 2 memories are of the same strength but different ages, the older will decay more slowly than the younger. The main theoretical implication of this venerable law has never been worked out, but it may be the same as that implied by Ribot's law. A consolidation interpretation of Jost's law implies an interference theory of forgetting that is altogether different from the cue-overload view that has dominated thinking in the field of psychology for decades.

Amnesia, Retrograde↗

PubMed2004

Local proactive interference in delayed matching to sample: the role of reinforcement.

Discriminability in delayed matching to sample was lower when the samples on consecutive trials differed compared with when samples on consecutive trials were the same. This local proactive interference occurred when correct choices on the previous trial were reinforced but not when correct choices on the previous trial were not reinforced. When the choice on the previous trial was incorrect, discriminability was higher on different consecutive trials than on same trials. These effects were amplified by varying the ratio of reinforcers for correct choices, as predicted by a model that attributes local proactive interference to an interaction between control by the sample on the current trial and the influence of reinforcers for correct choices on previous trials.

Animals↗

PubMed2004

Explaining purportedly irrational behavior by modeling skepticism in task parameters: an example examining confidence in forced-choice tasks.

Many purported demonstrations of irrational behavior rely on the assumption that participants believe key task parameters that are merely asserted by experimenters. For example, previous researchers have found that participants who first reported confidence in items presented in a yes-no format did not change confidence to the degree prescribed by the normative model when those same items were later presented in a forced-choice format. A crucial assumption, however, was that participants fully believed the assertion that the forced-choice items were mutually exclusive and exhaustive. In this article, the authors derive and test a new normative model in which it is not assumed that participants fully believe the assertion. Two visual identification experiments show that the new normative model provides a compelling account of participants' confidence reports.

Attitude↗

PubMed2004

The psychology and neuroscience of forgetting.

Traditional theories of forgetting are wedded to the notion that cue-overload interference procedures (often involving the A-B, A-C list-learning paradigm) capture the most important elements of forgetting in everyday life. However, findings from a century of work in psychology, psychopharmacology, and neuroscience converge on the notion that such procedures may pertain mainly to forgetting in the laboratory and that everyday forgetting is attributable to an altogether different form of interference. According to this idea, recently formed memories that have not yet had a chance to consolidate are vulnerable to the interfering force of mental activity and memory formation (even if the interfering activity is not similar to the previously learned material). This account helps to explain why sleep, alcohol, and benzodiazepines all improve memory for a recently learned list, and it is consistent with recent work on the variables that affect the induction and maintenance of long-term potentiation in the hippocampus.

Humans↗

PubMed2004

Stimulus salience and asymmetric forgetting in the pigeon.

Pigeons were trained using a symbolic delayed matching-to-sample procedure involving bright versus dim houselight samples. We hypothesized that when sample stimuli differ in salience, increasing the size of the retention interval will affect performance on trials initiated by the more salient sample only. In agreement with this prediction, accuracy following the dim sample did not decline as the retention interval increased, whereas accuracy following the bright sample declined to well below 50% correct. In a second experiment, the less salient (dim) sample from Experiment 1 was arranged as the more salient sample in a sample/no-sample procedure. Accuracy on dim sample trials then declined to well below 50% correct as the retention interval increased, whereas accuracy on no-sample trials remained constant. The results suggest that when sample stimuli differ in salience, pigeons may transform the nominal discrimination task into a detection task in which they respond on the basis of the presence or absence of the more salient sample.

Animals↗

PubMed2004

In defense of the signal detection interpretation of remember/know judgments.

Donaldson (1996) argued that remember/know judgments can be conceptualized within a signal detection framework by assuming that they are based on two criteria situated along a strength-of-memory decision axis. According to this model, items that exceed a high criterion receive a remember response, whereas items that only exceed a lower criterion receive a know response. Although a variety of findings have been presented in evidence against this idea, Dunn (2004) recently showed that detection theory is fully compatible with those findings. We present a variety of new results and new analyses that weigh strongly in favor of the detection interpretation. We further show that a dual-process account of recognition memory is compatible with a unidimensional detection model despite the common notion that such a model necessarily assumes a single process. The key assumption of this model is that individual recognition decisions are based on both recollection and familiarity (not on one process or the other).

Humans↗

PubMed2004

Recall and recognition are equally impaired in patients with selective hippocampal damage.

In two recent studies, the hypothesis that recall is more severely impaired than recognition in patients with damage thought to be limited to the hippocampus was tested. Yonelinas et al. (2002) reported findings that appeared to support this hypothesis, whereas Manns, Hopkins, Reed, Kitchener, and Squire (2003) found that recall and recognition were equally impaired. An analysis of the individual subject data from the two studies revealed that the apparent disagreement stemmed from the inclusion of a single outlying recognition score for 1 of the 55 control subjects in Yonelinas et al. (2002). When that outlier was excluded, the studies were in agreement that recognition and recall are substantially and similarly impaired in these patients. Yonelinas et al. (2002) also analyzed remember/know judgments and ROC data in an effort to show that recollection is selectively impaired in patients, but these analyses also raise problems.

Brain Damage, Chronic↗

PubMed2002

Cognitive theories as reinforcement history surrogates: the case of likelihood ratio models of human recognition memory.

B. F. Skinner (1977) once argued that cognitive theories are essentially surrogates for the organism's (usually unknown) reinforcement history. In this article, we argue that this notion applies rather directly to a class of likelihood ratio models of human recognition memory. The point is not that such models are fundamentally flawed or that they are not useful and should be abandoned. Instead, the point is that the role of reinforcement history in shaping memory decisions could help to explain what otherwise must be explained by assuming that subjects are inexplicably endowed with the relevant distributional information and computational abilities. To the degree that a role for an organism's reinforcement history is appreciated, the importance of animal memory research in understanding human memory comes into clearer focus. As Skinner was also fond of pointing out, it is only in the animal laboratory that an organism's history of reinforcement can be precisely controlled and its effects on behavior clearly understood.

Animals↗

PubMed2002

On the nature of the decision axis in signal-detection-based models of recognition memory.

Most models of recognition memory involve a signal-detection component in which a criterion is placed along a decision axis. Older models generally assume a familiarity-decision axis, but newer models often assume a likelihood ratio axis instead because it allows for a more natural account of the ubiquitous mirror effect. In 3 experiments reported here, item strength was differentially manipulated to see whether a mirror effect would occur. Within a list, the items from 1 category were strengthened by repetition, but the items from another category were not. On the subsequent recognition test, the hit rate was higher for the strong category, but the false-alarm rates for the weak and strong categories were the same (i.e., no mirror effect was observed). This result suggests that the decision axis represents a familiarity scale and that participants adopt a single decision criterion that they maintain throughout the recognition test.

Adult↗