Forgetting Research Articles

Executive control is shared between sentence processing and digit maintenance: Evidence from a strictly timed dual-task paradigm

We investigated whether the comprehension of syntactically difficult sentences taxes the executive control component of working memory more than the comprehension of their easier counterparts. To that end, we tested the effect of sharing executive control between sentence comprehension and the maintenance of a digit load in two dual-task experiments with strictly controlled timing (Barrouillet, Bernardin, & Camos, 2004). Recall was worse after participants had processed one (Experiment 2) or two (Experiment 1) difficult sentences than after they had processed one or two easy sentences, respectively. This finding suggests that sentence processing and the maintenance of a digit load share executive control. Processing syntactically difficult sentences seems to occupy executive control for a longer time than processing their easy counterparts, thereby blocking refreshments of the memory traces of the digits so that these traces decay more and recall is worse. There was no effect of the size of the digit load on sentence-processing performance (Experiment 2), suggesting that sentence processing completely occupied executive control until processing was complete.

The effect of time on word learning: An examination of decay of the memory trace and vocal rehearsal in children with and without specific language impairment

Purpose The purpose of this study was to measure the effect of time to response in a fast-mapping word learning task for children with specific language impairment (SLI) and children with typically developing language skills (TD). Manipulating time to response allows us to examine decay of the memory trace, the use of vocal rehearsal, and their effects on word learning. Method Participants included 40 school-age children: half with SLI and half with TD. The children were asked to expressively and receptively fast-map 24 novel labels for 24 novel animated dinosaurs. They were asked to demonstrate learning either immediately after presentation of the novel word or after a 10-second delay. Data were collected on the use of vocal rehearsal and for recognition and production accuracy. Results Although the SLI group was less accurate overall, there was no evidence of decay of the memory trace. Both groups used vocal rehearsal at comparable rates, which did not vary when learning was tested immediately or after a delay. Use of vocal rehearsal resulted in better accuracy on the recognition task, but only for the TD group. Conclusions A delay in time to response without interference was not an undue burden for either group. Despite the fact that children with SLI used a vocal rehearsal strategy as often as unimpaired peers, they did not benefit from the strategy in the same way as their peers. Possible explanations for these findings and clinical implications will be discussed. Learning outcomes: Readers will learn about how time to response affects word learning in children with specific language impairment and unimpaired peers. They will see how this issue fits into a framework of phonological working memory. They will also become acquainted with the effect of vocal rehearsal on word learning.

Processing of Complex Auditory Patterns in Musicians and Nonmusicians

In the present study we investigated the capacity of the memory store underlying the mismatch negativity (MMN) response in musicians and nonmusicians for complex tone patterns. While previous studies have focused either on the kind of information that can be encoded or on the decay of the memory trace over time, we studied capacity in terms of the length of tone sequences, i.e., the number of individual tones that can be fully encoded and maintained. By means of magnetoencephalography (MEG) we recorded MMN responses to deviant tones that could occur at any position of standard tone patterns composed of four, six or eight tones during passive, distracted listening. Whereas there was a reliable MMN response to deviant tones in the four-tone pattern in both musicians and nonmusicians, only some individuals showed MMN responses to the longer patterns. This finding of a reliable capacity of the short-term auditory store underlying the MMN response is in line with estimates of a three to five item capacity of the short-term memory trace from behavioural studies, although pitch and contour complexity covaried with sequence length, which might have led to an understatement of the reported capacity. Whereas there was a tendency for an enhancement of the pattern MMN in musicians compared to nonmusicians, a strong advantage for musicians could be shown in an accompanying behavioural task of detecting the deviants while attending to the stimuli for all pattern lengths, indicating that long-term musical training differentially affects the memory capacity of auditory short-term memory for complex tone patterns with and without attention. Also, a left-hemispheric lateralization of MMN responses in the six-tone pattern suggests that additional networks that help structuring the patterns in the temporal domain might be recruited for demanding auditory processing in the pitch domain.

Directed forgetting: an ERP research on postgraduate

Objective To investigate neural correlates of directed forgetting. Methods ERP was recorded from 12 healthy postgraduates while they performed a directed forgetting task based on the item-cueing method. During the study phase, each word was followed by a cue indicated that it need to be remembered, to be forgotten or just to be viewed. During the test phase, subjects were asked to make an old/new recognition response. One-way ANOVA of repeated-measurement and paired comparisons were carried out for the cue factor. Results Both of the accuracy and reaction time of the TBR group were significantly superior to those of the other two groups. No significant behavioral effect was found between the TBF group and the TBV group. In the study phase, statistical parametric mapping of ERP suggested the cue effects were presented in the frontal poles ( 200～300 ms ) and the parietal regions (300～400 ms) ,the left fronto-parietal and the right occipital region (450～700 ms). The difference between the TBF and the TBV was significant in the left parietal area (500～525 ms) and has the significant trend in the right frontal area ( 350～600 ms). In the retrieval phase, the old/new effects of ERP occurred in the left fro-nto-temporal (300～450 ms) for the TBF cue. Conclusions The TBF cue and the TBV cue have the equivalent behavioral performance. During the study period, the activation of the right frontal lobe and the left parietal suggests the active inhibition evoked by the TBF cue. And the TBR cue can enhance the rehearsal function of left hemisphere and improve the memory performance of words. The retrieval of the items of TBF is based on more familiarity and less recollection. Key words: Directed forgetting; Item-cuing method; Event-related potentials

Models of trace decay, eligibility for reinforcement, and delay of reinforcement gradients, from exponential to hyperboloid

Behavior such as depression of a lever or perception of a stimulus may be strengthened by consequent behaviorally significant events (BSEs), such as reinforcers. This is the Law of Effect. As time passes since its emission, the ability for the behavior to be reinforced decreases. This is trace decay. It is upon decayed traces that subsequent BSEs operate. If the trace comes from a response, it constitutes primary reinforcement; if from perception of an extended stimulus, it is classical conditioning. This paper develops simple models of these processes. It premises exponentially decaying traces related to the richness of the environment, and conditioned reinforcement as the average of such traces over the extended stimulus, yielding an almost-hyperbolic function of duration. The models account for some data, and reinforce the theories of other analysts by providing a sufficient account of the provenance of these effects. It leads to a linear relation between sooner and later isopreference delays whose slope depends on sensitivity to reinforcement, and intercept on that and the steepness of the delay gradient. Unlike human prospective judgments, all control is vested in either primary or secondary reinforcement processes; therefore the use of the term discounting, appropriate for humans, may be less descriptive of the behavior of nonverbal organisms.

A Study on the Constitution Type-Specific Presentation of Physical Symptoms

1. Objectives: This clinical study was conducted to understand the differences between Sasang constitutional types and to identify the physical symptoms presentation specific to each Sasang constitutional type. 2. Methods: In this descriptive study, 2,629 subjects (1,061 Taeeum-type, 683 Soeum-type, 885 Soyang-type) were surveyed between Nov 1, 2007 and Jul 31, 2010. The subjective symptoms experienced by the subjects were collected using a Physical Symptoms questionnaire, and the subjects were interviewed by Sasang specialists who determined the subjects' constitutional type. The data (in crude number and percentage) was analyzed on the general characteristics, Sasang constitutional type, and physical symptoms using the SPSS 17.0 software. The symptomatic presentation in men and women were analyzed on Sasang constitutional distribution using the chi-square test. 3. Results: 1) The physical symptoms specific to each Sasang constitutional type were as follows: 'frequent aphthous lesions in the oral cavity', 'lingering fatigue after sleep', 'headache', 'common cold symptoms presenting as loss of appetite or indigestion', and 'physical deterioration presenting as problems with digestion' in the Soeum type; 'physical deterioration presenting as problems in perspiration' and 'swelling and puffiness' in the Taeeum type; and 'excessive forgetfulness' in the Soyang type. 2) The physical symptoms specific to each Sasang constitutional type in men were as follows: 'Unilateral or bilateral headaches, 'frequent aphthous lesions in the oral cavity', 'common cold symptoms presenting as rhinorrhea or nasal congestion', 'common cold symptoms presenting as loss of appetite or indigestion', and 'physical deterioration presenting as problems with digestion' in the Soeum type; and 'swelling and puffiness' in the Taeeum type. 3) The physical symptoms specific to each Sasang constitutional type in women were as follows: 'common cold symptoms presenting as headaches', 'common cold symptoms presenting as loss of appetite or indigestion', 'physical deterioration presenting as problems with digestion' in the Soeum type; and 'pain in knees', 'redness of eyes', 'dryness of mouth', 'common cold symptoms presenting as coughing', 'physical deterioration presenting as problems in perspiration', 'swelling and puffiness' in the Taeeum type. 4. Conclusions: This study demonstrates that physical symptoms present in constitutional type-specific patterns. Understanding of the personal Sasang constitutional type and systematic, personalized healthcare based on constitutional typology is anticipated to contribute to improved health management strategy.

Further evidence for temporal decay in working memory: Reply to Lewandowsky and Oberauer (2009).

The sources of forgetting in working memory (WM) are a matter of intense debate: Is there a time-related decay of memory traces, or is forgetting uniquely due to representation-based interference? In a previous study, we claimed to have provided evidence supporting the temporal decay hypothesis (S. Portrat, P. Barrouillet, & V. Camos, 2008). However, reanalyzing our data, S. Lewandowsky and K. Oberauer (2009) demonstrated that they do not provide compelling evidence for temporal decay and suggested a class of alternative models favoring a representation-based interference account. In this article, we develop from the most recent proposals made by Lewandowsky and Oberauer 2 of the most plausible extensions of these alternative models. We show that neither of these extensions can account for recent findings related to between-domain WM performance and that both lead to predictions that are contradicted by new empirical evidence. Finally, we show that recent studies that have been claimed to rule out the temporal decay hypothesis do not resist close scrutiny. We conclude that the time-based resource-sharing model remains the most parsimonious way to account for forgetting and restoration of memory traces in WM.

Alternation Frequency Thresholds for Stereopsis as a Technique for Exploring Stereoscopic Difficulties

When stereoscopic images are presented alternately to the two eyes, stereopsis occurs at F ≥ 1 Hz full-cycle frequencies for very simple stimuli, and F ≥ 3 Hz full-cycle frequencies for random-dot stereograms (eg Ludwig I, Pieper W, Lachnit H, 2007 “Temporal integration of monocular images separated in time: stereopsis, stereoacuity, and binocular luster” Perception & Psychophysics 69 92–102). Using twenty different stereograms presented through liquid crystal shutters, we studied the transition to stereopsis with fifteen subjects. The onset of stereopsis was observed during a stepwise increase of the alternation frequency, and its disappearance was observed during a stepwise decrease in frequency. The lowest F values (around 2.5 Hz) were observed with stimuli involving two to four simple disjoint elements (circles, arcs, rectangles). Higher F values were needed for stimuli containing slanted elements or curved surfaces (about 1 Hz increment), overlapping elements at two different depths (about 2.5 Hz increment), or camouflaged overlapping surfaces (> 7 Hz increment). A textured cylindrical surface with a horizontal axis appeared easier to interpret (5.7 Hz) than a pair of slanted segments separated in depth but forming a cross in projection (8 Hz). Training effects were minimal, and F usually increased as disparities were reduced. The hierarchy of difficulties revealed in the study may shed light on various problems that the brain needs to solve during stereoscopic interpretation. During the construction of the three-dimensional percept, the loss of information due to natural decay of the stimuli traces must be compensated by refreshes of visual input. In the discussion an attempt is made to link our results with recent advances in the comprehension of visual scene memory.

Modeling working memory: a computational implementation of the Time-Based Resource-Sharing theory

Working memory is a core concept in cognition, predicting about 50% of the variance in IQ and reasoning tasks. A popular test of working memory is the complex span task, in which encoding of memoranda alternates with processing of distractors. A recent model of complex span performance, the Time-Based-Resource-Sharing (TBRS) model of Barrouillet and colleagues, has seemingly accounted for several crucial findings, in particular the intricate trade-off between deterioration and restoration of memory in the complex span task. According to the TBRS, memory traces decay during processing of the distractors, and they are restored by attentional refreshing during brief pauses in between processing steps. However, to date, the theory has been formulated only at a verbal level, which renders it difficult to test and to be certain of its intuited predictions. We present a computational instantiation of the TBRS and show that it can handle most of the findings on which the verbal model was based. We also show that there are potential challenges to the model that await future resolution. This instantiated model, TBRS*, is the first comprehensive computational model of performance in the complex span paradigm. The Matlab model code is available as a supplementary material of this article.

Review of Rediscovering psychoanalysis: Thinking and dreaming, learning and forgetting.

Review of Rediscovering psychoanalysis: Thinking and dreaming, learning and forgetting.

Decay of iconic memory traces is related to psychometric intelligence: A fixed-links modeling approach

Several memory processes have been examined regarding their relation to psychometric intelligence with the exception of sensory memory. This study examined the relation between decay of iconic memory traces, measured with a partial-report task, and psychometric intelligence, assessed with the Berlin Intelligence Structure test, in 111 participants. Using a fixed-links modeling approach, the exponential decay of iconic memory traces was quantified and separated from the effects of (systematic variance due to) subsidiary processes unrelated to this decay. Higher psychometric intelligence was associated with slower decay of iconic memory traces even when the influence of selective and divided attention was controlled for. These findings provide first experimental evidence for a functional relationship between information processing in sensory memory and individual levels of psychometric intelligence. The use of fixed-links models is discussed with regard to delineating processes in a repeated-measures design.

The intentional forgetting to emotional words of PTSD children after Wenchuan earthquake 18 months

Objective To compare the ability of intentional forgetting to emotional words of post traumatic stress disorder(PTSD) children and normal children by item method after Wenchuan earthquake 18 months.Methods Twenty PTSD children who met with CCMD-3 and DSM-Ⅳ criteria and twenty control group children were investigated. Sixteen positive and sixteen negative words were adopted as materials. PTSD children accomplished the words learning, arithmetical operation and memory tests ( include free recall, words completion and words recognition) in orderly. Results ( 1 )The free recall accuracy of PTSD children to positive words was significant high than negative words( (0.32 ±0.11 ), (0.28 ±0.10), P＜0.05). The free recall accuracy of control group to positive words was significant high than negative words ( (0.37 ± 0.09 ), (0.34 ± 0.13 ), P＜ 0.05 ). ( 2 )The words completion accuracy of PTSD children to positive words was significant low than negative words( (0.38± 0.12 ), (0.49 ± 0.12 ), P ＜ 0.05 ). The words completion accuracy of control group to positive words was significant low than negative words ( (0.39 ± 0.15 ), (0.56 ± 0.14 ), P ＜ 0.01 ). ( 3 ) There was no difference of words recognition accuracy of PTSD children to positive and negative words ( ( 0.64 ± 0. 19 ), (0.63 ± 0. 16), P ＞0. 05). There was no difference of words recognition accuracy of control group to positive and negative words ((0.64 ± 0. 16), (0.65 ±0. 19), P ＞ 0. 05). Conclusion There is a significant intentional forgetting effect on emotional words in PTSD children and normal children, and this effect were influenced not only by selective rehearsal but also retrieval inhibition. Key words: Post traumatic stress disorder; Earthquake; Children; PTSD children; Emotional words; Intentional forgetting

Pharmacological Forgetting

Pharmacological Forgetting

Study of the correlation of clinical symptoms,mental health and plasma cortisol level of post-traumatic stress disorder

Objectives To study the correlation of clinical symptoms,mental health and plasma cortisol levels of post-traumatic stress disorder(PTSD).Methods According to diagnostic and statistic manual of mental disorders,4th ed(DSM-Ⅳ)criteria,all subjects were divided into PTSD group and non-PTSD group.PTSD symptoms were investigated and subjects were assessed with Symptom Checklist-90(SCL-90)and Eysenck Personality Questionnaire(EPQ).Radio-immunity technique was used to test plasma cortisol concentration.Results The most common of PTSD symptoms were markedly diminished interest or participation in significant activities (94.29%),irritability or outbursts of anger(94.29%)and difficulty falling or staying asleep(91.43%)respectively.There were different in PTSD symptoms,but recurrent and intrusive distressing recollections of the events,recurrent illusions and hallucinations and selective forgetting,between PTSD group and non-PTSD group(P＜0.05).Plasma cortisol concentrations in patients with PTSD((281.57±123.93)ng/ml)and those without PTSD ((243.39±125.60)ng/ml)were all lower than that in normal controls((344.21±86.76)ng/ml,P=0.037,P=0.009).In Pearson correlation model,plasma cortisol was significantly positive correlated with interpersonal sensitivity(r=0.446,P=0.008),depression(r=0.428,P=0.019)of SCL-90 and neuroticism(r=0.380,P=0.026)of EPQ.Conclusions People with traumatic events have some PTSD symptoms.Plasma cortisol concentrations in patients with PTSD axe lower than those in normal controls.And plasma cortisol are significantly positive correlated with interpersonal sensitivity,depression and neurotieism. Key words: Post-traumatic stress disorder; Cortisol; Pearson correlation analysis

Memory – mechanisms, tools and aids

Memory loss is an abnormal degree of forgetfulness and inability to retrieve past experiences and events. Nootropic agents act on brain to improve the cognitive function. They are used for the treatment of amnesia or dementia, occurring due to the disturbance of neuronal mechanism in various pathological conditions. Long-term potentiation (LTP) is a well-accepted molecular mechanism of learning and memory. Neurotransmitters such as GABA, Nor-epinephrine, dopamine, acetylcholine etc and their receptors are also reported to modulate learning and memory. Impairment in the physiological process of LTP produces memory deficits. Moreover, antioxidant, metabolic enhancers, chelators, nerve growth factors and calcium channel blockers have been reported to decline the progress of neurodegeneration and improve the cognition. Drugs, obtained from various plant sources, are now tested in animals and humans with hope of inventing newer therapeutic agents. doi : 10.5214/ans.0972.7531.2009.160308 Competing interests: None. Source of Funding: None Received Date: 29 May 2009 Revised Date: 24 June 2009 Accepted Date: 11 July 2009

Behavioral effects of agmatine in naive rats are task- and delay-dependent

The present study systematically investigated the effects of agmatine administered i.p. in several commonly used behavioral tasks. In Experiment 1, pre-test treatment of agmatine (1 and 40 mg/kg) appeared to improve animals' performance in the water maze probe test conducted 24 h, but not 120 s, after training, when the effect was evaluated within subjects. In Experiment 2, pre-test agmatine treatment (40 mg/kg) did not affect animals' performance in the open field, and the place navigation, probe tests (1–4 and 6), reversal test and cued navigation in the water maze, but significantly facilitated performance in probe 5 which was conducted 96 h after training. In Experiment 3, rats with pre-test agmatine treatment (40 mg/kg) were less anxious relative to the controls, with no performance changes in the open field. In the water maze task, post-training agmatine treatment (40 mg/kg) did not affect place and cued navigation, but significantly improved animals' performance in the probe test conducted 24 h after training and the reversal test. In the working memory version of the task, agmatine treated rats took significantly less time and generated markedly shorter path length to reach the platform at the 180 s, but not 30 s, delay relative to the controls. In the object recognition task, rats with pre-test agmatine treatment (40 mg/kg) spent significantly more time exploring displaced objects, but not novel object, as compared to the controls. In Experiment 4, pre-test agmatine treatment (40 mg/kg) had no effect on the task acquisition in the delayed non-match to position task in the T-maze, but significantly facilitated performance at the 600 s delay. These results suggest that the behavioral effects of agmatine are task- and delay-dependent, and agmatine facilitates memory particularly when the task difficulty is increased due to memory trace decay and/or greater interference.

Introspective forgetting

Introspective forgetting

Emplotting Forgiveness: Narrative, Forgetting and Memory

Emplotting Forgiveness: Narrative, Forgetting and Memory

The characteristics of directed forgetting with depressed college students

Objective To study the characteristics of directed forgetting between non-depressed subjects and depressed individuals. Methods 40 non-depressed subjects and 40 depressed individuals performed the word method of directed forgetting task, then recorded and analyzed the accuracy rate and response time. Non-depressed subjects and 40 depressed individuals performed the word method of directed forgetting task, then recorded and analyzed the accuracy rate and response time. Results ①There was obvious directed forgetting effect in free recall stage between normal and depressed subjects, difference significantly to negative, positive materials(1.84±0.87 vs 0.86±0.89,t =5.15,P ＜0.01;1.14±0.71 vs 0.67±0.75,t =2.96,P ＜0.01).②The reverse phenomenon of directed forgetting was found in recognition stage, especially in depressed subjects(8.66±1.84 vs 9.62±1.84,t =2.25,P ＜0.05). ③Behavior data showed that normal controls were better than depressed subjects(84.40±0.20,78.70±17.71,P ＜0.05),but no typically differences in reaction time( P ＞0.05).Conclusion Different information processing was present between normal and depressed subjects. Normal controls may remember positive and forget negative materials better, reverse the depressed .It is concluded that the directed forgetting task could be improved and extended to investigate cognition-emotion fields usefully. Key words: Depressive symptom; Directed forgetting; College students

Reconsidering the two-second decay hypothesis in verbal working memory

A common belief in the study of short-term memory is that the verbal trace decays around two seconds after it is encoded. This belief is typically assumed to follow from the finding that in immediate serial recall, the time required to rapidly articulate a span-length list is around two seconds. Empirically, this belief is in opposition to a broad set of findings across a number of domains that establish mean decay times to be longer than two seconds. Theoretically, the available computational and mathematical models of immediate serial recall do not address this issue directly, because they typically rely on other mechanisms in addition to decay to account for forgetting. As such, they may show that decay times can be longer than two seconds, but they fail to show that they cannot be as short as two seconds. We address the issue directly and set a lower bound on mean trace decay times, even under the limiting assumption that all forgetting is due to trace decay. We do this by presenting a simple item-based model of trace decay that allows us to estimate values of mean trace duration. For a set of words whose span-length lists can be rapidly articulated in about two seconds, the model offers a conservative estimate for their mean decay times of around four seconds. Both the experimental and theoretical evidence show that items in verbal working memory decay considerably slower than the two-second decay hypothesis claims.