Picture memory improves with longer on time and off time.

Both recognition and recall of pictures improve as picture presentation time increases and as time between pictures increases. Processing of the pictures, rehearsal and/or encoding, continues after the picture has disappeared, just as for verbal material. Both the results and conclusions stand in contrast to those of Shaffer and Shiffrin.     

Short-term memory in the pigeon with presentation time precisely controlled

Delayed matching-to-sample was studied in the pigeon using a procedure which precisely controlled the presentation time of the sample stimulus. Experiments 1 and 2 revealed that (a) accuracy of matching increased as a negatively accelerated function of presentation time, (b) accuracy declined when an interstimulus interval was introduced between successive presentations of the sample stimulus, and (c) the rate at which accurate matching was restored after an interstimulus interval was greatest when the initial presentation of the sample was short and the interval was long. It was concluded that a theory of STM based on the growth and decay of trace strength could account adequately for all of these findings. Experiment 3 studied trace interaction by presenting two sample stimuli first in succession and then simultaneously for choice. Predictions from trace competition theory about the specific lengths of presentation of these stimuli at which choice of the second stimulus should be 50% or deviate systematically below 50% were not supported. It appears that a recency mechanism in addition to competition is necessary to explain trace interaction effects.     

Study time effects in recognition memory

We empirically tested the assumption that study time increases recognition accuracy because the storage of information is better when study time is longer as Shiffrin and colleagues have reported, an assumption common to parallel models of recognition. In the present study with 123 subjects, we examined the effect of item strength on four measures: hit rate, false alarm rate, d', and beta, for a single-word recognition task with longer study times than those usually used in the literature. Analysis indicated significant increase for hit rate and d' and a decrease in false alarm rate, as one goes from weak to stronger study conditions, and a change in ln(beta) when study time is greater than 1 sec. These results suggest that familiarization is one, but not the only, factor underlying the strength-mirror effect.     

Short-term memory for time intervals

The effect of intertrial interval, preset interval, and retention interval on the performance of rats in a time estimation task was described. On each trial a signal was presented for a duration of 2 to 8 sec. Eighteen rats were trained to press one lever (the short response) if the signal was shorter than 4 sec, and another lever (the long response) if the signal was longer than 4 sec. When trials were massed (Experiment 1), the percentage long response was affected by the classification of the previous signal, but not by its actual duration. This suggests that the animals remembered the response made on the previous trial, but not the signal duration. If a response was not permitted on the previous trial (Experiment 2), the duration or classification of the previous signal had no effect on performance. This supports the conclusion from the first experiment and suggests that an animal can reset its internal clock in less than 2 sec. In Experiment 3, the difference limen of the psychophysical function increased with the duration of the retention interval, but the point of subjective equality did not change. This suggests that resetting of the internal clock occurs on a non-time dimension.     

Asymmetry in updating long-term memory for time

The present study evaluates the updating of long-term memory for duration. After learning a temporal discrimination associating one lever with a standard duration (4 sec) and another lever with both a shorter (1-sec) and a longer (16-sec) duration, rats underwent a single session for learning a new standard duration. The temporal generalization gradient obtained 24 h later showed a modification in long-term memory for durations longer than the standard but only when the new duration was longer than the one initially learned. The effect was confirmed for another set of durations (0.5–2–8 sec). Our study demonstrates asymmetry in updating long-term memory for time.

Learning and memory updating are based on error detection, so that learning/updating occurs when something new happens. Time-based error detection supposes a comparison between current tracked time and stored/memorized time of the expected event. This is what is at work when on your usual way back home you are judging that the traffic light is broken because it has stayed red for too long, based on your memory of that traffic light duration.Memory of time has been invoked in early treatments of timing (Pavlov 1927; Treisman 1963; Gibbon 1977). Animal research has shown that long-term memory for time is formed in a single session, or even in a single trial (Balsam et al. 2010; Diaz-Mataix et al. 2013; Tallot et al. 2020), while human research has recently shown that it follows biological rules, such as a consolidation time course during the hours following encoding (Cocenas-Silva et al. 2014), which are different from those underlying temporary storage of duration. An in-depth investigation of the neural bases of long-term memory for time requires research in animals, in protocols that isolate the learning of duration from any other aspects of the task (e.g., contingencies and rules).One protocol is to shift temporal contingencies after the initial learning of the task has been stabilized in performance, and observe how updating occurs at the behavioral level. With this approach, human research has mainly concentrated on temporal reference memory created and manipulated within a single session, and thus has not studied its long-term form. For example, Ogden et al. (2008) reported interference in memory, as the temporal generalization gradient for a recently encoded duration was altered by the introduction of another generalization task, whether the new standard was of a shorter or longer duration. Also showing effects in both directions, Simen et al. (2011) found rapid adaptation to successive new, longer or shorter, time targets. Animal research has analyzed the dynamics of behavioral adaptation to new fixed interval (FI) values (e.g., Meck et al. 1984; Lejeune et al. 1997) or CS–US interval in a Pavlovian paradigm (Dallérac et al. 2017), changes in the duration–action association in temporal discrimination tasks (Church and Deluty 1977), or through the demonstration of averaging of time (FI) memories (e.g., Swanton et al. 2009; De Corte and Matell 2016). The difficulty with all these approaches is that they often necessitate several sessions to extract/analyze the behavioral outcome, while memory for the new time is presumably updated and consolidated within hours after the first session. In addition, the behavioral adaptation may differ depending on the magnitude and direction of the difference between the new relevant temporal values and those (shorter or longer) stored in long-term memory (Higa 1997; Lejeune et al. 1997). Importantly also is the fact that these approaches mix two factors: the learning of the new temporal rule and the behavioral adaptation to it, which likely depends on the behavioral protocol used, thus rendering interpretation of effects difficult to link with a specific factor. This may also explain in part why the results are conflicting with sometimes fast adaptation, or in contrast slow adaptation, or even no adaptation to new temporal rules.The aim of the present study was to assess in rats the ability to update in long-term memory a duration memorized in a single session. We developed a temporal generalization procedure, akin to human studies of memory for time (Cocenas-Silva et al. 2014; Derouet et al. 2019), enabling the use of both shorter or longer durations while isolating the formation of a new temporal memory through the investigation of the extent to which it interferes with an already formed stabilized memory. Rats were trained (temporal discrimination training) (see the Supplemental Material) to press one lever (left or right) after a 4-sec tone stimulus duration and the other lever after a shorter (1-sec) or longer (16-sec) tone duration, as an equivalent to the “same” versus “different” task in the training phase for temporal generalization assessment in humans (Wearden 1992). Reward (food pellet) was given if the correct lever was pressed. All the animals showed a good general level of acquisition and discrimination between the durations (see the Supplemental Material). Animals were then assigned to four groups, equilibrated according to their acquisition performance (Supplemental Fig. S1). For three groups, animals were submitted to a single session (called shift session) with 20 trials in which only one lever, the lever associated with the standard 4-sec duration, was presented at the end of the tone, but the tone duration was shorter than (2.5 sec), longer than (6.3 sec), or the same as (4.0 sec, no shift) the standard duration. Animals in the fourth group (control) remained in the colony room. Generalization tests were performed on the following 2 d, with six intermediate durations (2, 2.5, 3.2, 5, 6.3, 8 sec; 10 trials each) not reinforced, in addition to the standard duration (4 sec for 30 trials) and the two “extreme” durations (1 sec and 16 sec for 15 trials each) for which correct responding was reinforced.The generalization gradients obtained on the first day of tests, 24 h after the shift session, differed between groups, and more so for the durations longer than the standard (Fig. 1A). An analysis of variance (ANOVA) performed on the proportion of responses to the lever associated with the 4-sec standard duration, p(4 sec), with one between-subjects factor (four groups) and one within-subject factor (seven stimulus durations, excluding the reinforced extreme durations) showed a significant main effect of stimulus duration, F_(6,408) = 46.88, P < 0.001, confirming that rats did effectively discriminate between durations. However, there was a significant stimulus duration × group interaction, F_(18,408) = 1.892, P = 0.046, while the main effect of group was not significant F_(3,68) < 1. This indicated that rats responded differently among groups depending on the durations. Parsing the interaction, separate analyses, with stimulus durations shorter (2, 2.5, 3.2 sec) and longer (5, 6.3, 8 sec) than the standard (4-sec) duration, revealed a significant stimulus duration × group interaction for long stimulus durations, F_(6,136) = 4.050, P = 0.001, but not for short-stimulus durations, F_(6,136) = 1.494, P = 0.188. Thus, the impact of the Shift session was specifically on stimulus durations longer than the standard duration. To characterize the effect, further comparisons were made restricted to these long stimulus durations. First, the 4-sec group did not differ significantly from the control group (no significant interaction or group differences, both Fs < 1). This demonstrated that the procedure itself (i.e., a forced-choice session with a single “standard” duration) did not produce a change in temporal generalization gradient. Second, compared with the 4-sec group, only the group of animals that experienced a shift session with a new standard >4 sec showed a significantly modified generalization gradient (6.3-sec group: interaction, F_(2,68) = 5.236, P = 0.010, group effect, F_(1,34) < 1); 2.5-sec group: interaction, F_(2,68) = 1.501, P = 0.232, group effect, F_(1,34) = 1.662, P = 0.206). Analysis of individual slopes of regression confirmed that the decay magnitude of the generalization gradient differed among groups, F_(3,68) = 6.38, P < 0.001, and that only the 6.3-sec group differed from all the other groups, that is, the control group (Bonferroni, P = 0.035), the 4-sec group (P = 0.05), and the 2.5-sec group (P < 0.001) (Fig. 1A, inset). None of the other comparison pairs was significant (Ps ≥ 0.738) (see Supplemental Fig. S2 for individual curves and slopes of regression for the rising and decay parts of the generalization gradient). Thus, the shift session with a new temporal reference had a significant impact only when it was to a longer duration than the initially learned standard duration, and the impact was asymmetrical with a flattening of the generalization gradient only for the stimulus durations longer than the standard duration.Open in a separate windowFigure 1.Proportion of lever presses on the 4-sec lever -p(4 sec)- plotted against stimulus duration for the control, 4-, 2.5-, and 6.3-sec groups for the first (A) and the second (B) day of the generalization task. Error bars: ±SEM. (Insets) Slope of the regression fitted on p(4 sec) for 5-, 6.3-, and 8-sec test durations for each rat for the four groups, with a dotted line linking the group mean values. (*) Bonferroni P ≤ 0.05, significant difference between the 6.3-sec group and each of the other groups.As the original discrimination rules were in effect during the generalization test (i.e., retraining with the standard [4-sec] and extreme durations reinforced), the impact of the shift session should diminish with retraining. As expected, apart from the main effect of stimulus duration, F_(6,408) = 84.261, P < 0.001, showing that the rats still discriminated among durations, there were no other significant effects during the second day of the generalization test (effect of group and stimulus duration × group interaction, both Fs < 1, ns) (Fig. 1B). Thus, the disruption of temporal judgment observed in the generalization test originated from the interference effects of the new temporal rule in the shift session, and reflected a rapid update in memory of the duration/action association rather than a general irreversible disturbance of behavior.The asymmetry in the temporal generalization gradient suggesting interference effects only on the judgment of stimulus durations longer than the standard duration raises the question of whether it reflects an effect specific to the range of durations used in our study, with judgment of durations <4 sec being immune to interference. It is also possible that memory updating requires a minimum temporal difference from the standard duration (2.3 sec vs. 1.5 sec, for shifts to longer and shorter durations, respectively). To address this issue, a new set of animals was trained on a discrimination between a 2-sec tone standard duration associated with a given lever, and either a 500-msec or 8-sec tone duration associated with the second lever (see the Supplemental Material). A shift session with a 3.15-sec tone duration (i.e., 1.15-sec difference from the standard) was given for one group compared with another group for which the 2-sec standard duration was not changed. The performance criterion was reached by both groups for the standard and long duration, but not for the 500-msec tone (see the Supplemental Material; Supplemental Fig. S3). Performance during the first day of the generalization test (1.25, 1.60, 2.5, 3.15 intermediate durations) run 24 h after the shift session showed an impact of the shift session when the new 3.15-sec duration was associated with the lever corresponding to the 2-sec standard duration, compared with when there was no change in duration (Fig. 2A). The mixed ANOVA performed on p(2 sec) confirmed that rats discriminated between durations (main effect of stimulus duration, F_(6,210) = 12.212, P < 0.001), with no significant main effect of group, F_(1,35) < 1, but a significant stimulus duration × group interaction, F_(6,210) = 3.483, P = 0.008), indicating that rats responded differently between groups depending on the stimulus durations. As in the previous experiment, a significant stimulus duration × group interaction appeared for stimulus durations longer (2.5, 3.15, 4 sec), F_(2,70) = 7.612, P = 0.001, but not for those shorter (1, 1.25, 1.60 sec) than the standard duration (F < 1). Analysis of individual slopes of regression confirmed a significant difference between the two groups for the decay part of the generalization gradient (F_(1,35) = 9.65, P = 0.004) (Fig. 2A, inset; see Supplemental Fig. S4 for individual curves and slopes of regression for the rising and decay parts of the generalization gradient). Also as before, the effect was no longer visible on the second day of generalization test (F < 1 for group effect and stimulus duration × group interaction) (Fig. 2B) while the main effect of stimulus duration remained significant, F_(6,210) = 14.580, P < 0.001). Thus, a 1.15-sec shift in the duration/action association within a range of durations <4 sec triggered an update in memory with an impact restricted specifically to durations longer than the standard duration. This effect was comparable with the one observed when the standard duration was 4 sec in duration and the memory update was to a longer duration with the same magnitude on a geometric scale (factor 1.575).Open in a separate windowFigure 2.Proportion of lever presses on the 2-sec lever -p(2 sec)- plotted against stimulus duration for the 2-sec and 3.15-sec groups for the first (A) and the second (B) day of generalization task. Error bars: ±SEM. (Insets) Slope of the regression fitted on p(2 sec) for 2.5-, 3.15-, and 4-sec test durations for each rat for the two groups, with a dotted line linking the group mean values. (*) Bonferroni P ≤ .05, significant difference between the 3.15-sec group and the 2-sec group.In all, the results show that a single session pairing a new duration with a learned response interferes with an already formed long-term memory of a duration–action association. This result first provides further support for rapid learning of duration, extending the previous findings in Pavlovian settings in which a single trial was shown to suffice for learning an interval between conditioned and unconditioned stimuli (Balsam et al. 2010; Diaz-Mataix et al. 2013). In instrumental tasks, only few studies have examined the time course of behavioral adaptation, and the majority of them used paradigms in which the animals were repeatedly exposed to shifts in fixed interval values, and therefore may have learned to adapt. Nevertheless, when analyzed, the behavioral shifts were rapid, if not in a single trial (e.g., Higa et al. 2002).The procedure we implemented here enabled us to highlight two, possibly independent, sources of asymmetry: (1) Memory updating was produced when the new standard duration was longer (upshift), but not shorter (downshift), than the initially trained standard duration. (2) The impact of the interference on the generalization gradient (i.e., flattening of the curve) was restricted to durations longer than the standard. The asymmetry cannot be due to a differential detection of temporal changes, as their sizes were equivalent on a geometric scale (in all upshift and downshift conditions), or even opposite to the effect predicted when comparing the two experiments on an arithmetic/absolute scale (significant impact of a 1.15-sec upshift in experiment 2 vs. no impact of a bigger 1.5-sec downshift in experiment 1). These asymmetrical effects resonate with previous reports showing asymmetries in the adaptation to new fixed interval values or to new duration/action association, albeit not always in the same direction. Shifts in fixed or peak interval schedules in rodents have produced mixed results, with reports of either symmetry or a tendency for faster adaptation to longer durations (e.g., Meck et al. 1984; Lejeune et al. 1997) or, in contrast, slower, or in some instances, no adaptation to the new schedule when the shift was to a longer duration, but faster adaptation when the shift was to a shorter duration (e.g., Higa 1996; 1997; Higa and Tillou 2001). Furthermore, readaptation to a short duration after a shift to longer duration is very rapid (Higa and Tillou 2001), which stands in contrast to our results, which could be interpreted as a fast learning of a longer duration and/or slow readaptation to a shorter duration. Previously reported asymmetries in adaptation to changing FI schedules may be partly explained through the learned anticipation of upcoming shifts, due to the repetition of shifts (Sanabria and Oldenburg 2014).Our results may be better compared with tasks involving choice rather than anticipatory responding. In the temporal bisection task, no asymmetry has been reported in rats after shift to new duration/action pairings, whether to shorter or longer ranges (Church and Deluty 1977), but some asymmetry has been reported in pigeons with a noticeable change in behavior mainly when the long anchor duration was lengthened (Machado and Keen 2003), whose magnitude may depend on the initial training condition (Araiba and Brown 2017). In this type of task, categorization processes may be at play in addition to temporal generalization, possibly rendering the behavior less sensitive to changes in duration. However, the present observed asymmetry would suggest that the short and standard durations may have belonged to the same category, which is opposite to findings in the literature (Russell and Kirkpatrick 2007). Although our paradigm involved a discrimination task similar to the same/different task and temporal generalization gradient test used in humans, it can also be regarded as a discrimination with three—short versus standard versus long—durations, and a “dual”-bisection task during tests with intermediate duration values. The standard duration in our paradigm could be considered as a “long” anchor for the short–standard discrimination, but as a “short” anchor for the standard–long discrimination. In the first case, larger changes in behavior would be expected in the upshift condition than in the downshift condition (Araiba and Brown 2017), whereas in the second case no change would be expected (Machado and Keen 2003). Our results seem congruent with the reported asymmetry in the first case, and may also explain the lack of modification in the temporal generalization for the range of durations shorter than the standard duration.By restricting the change in duration/action association to a single session of interference, rather than looking at repetitive or stable adaptation of behavior to new temporal contingencies, our experiment reveals new information about how a duration is learned and memorized in long-term memory, to serve as a reference for later comparison when choices are made. We show that memory updating happens rapidly and the new temporal reference is memorized for long-term storage for at least 24 h. Our results, however, clearly point to an asymmetry in updating the memory, an asymmetry that was also suggested in our recent experiment in humans (Derouet et al. 2019). Whether the asymmetry originates from an asymmetrical detection of changes, that is, shorter versus longer than the standard duration, or from differential speed of learning and/or adaptation to temporal contingencies will need to be addressed in future investigations. The present novel paradigm will enable answering these questions and provide grounds for fruitful assessments of the neurobiological basis of memory for time, critical for time-based error monitoring and adaptation of behavior to novel contingencies.     

Time-based prospective memory difficulties in children with ADHD and the role of time perception and working memory

Time-based prospective memory (PM) is the ability to remember to perform an intended action at a given time in the future. It is a competence that is crucial for effective performance in everyday life and may be one of the main causes of problems for individuals who have difficulty in planning and organizing their life, such as children with attention deficit/hyperactivity disorder (ADHD). This study systematically examines different aspects of time-based PM performance in a task that involves taking an action at a given future time in a group of 23 children with ADHD who were compared with a matched group of typically-developing (TD) children. The children were asked to watch a cartoon and then answer a questionnaire about its content (ongoing task). They were also asked to press a key every 2 minutes while watching the cartoon (PM task). The relationships of time perception and verbal working memory with PM performance were examined by administering appropriate tasks. The results showed that the children with ADHD were less accurate than the TD children in the PM task and exhibited less strategic time-monitoring behavior. Time perception was found to predict PM accuracy, whereas working memory was mainly involved in time-monitoring behavior, but this applied more to the TD group than to the ADHD group, suggesting that children with ADHD are less able to use their cognitive resources when meeting a PM request.     

Stimulus exposure time and perceptual memory

The recent explosion of research on implicit memory has facilitated the examination of perceptual and conceptual processes in the encoding of information. Nevertheless, stimulus exposure time—the amount of time that a stimulus is physically available to a perceiver’s scrutiny—has received little attention. In the present paper, we examine the effect of stimulus exposure time on three implicit memory measures (word-fragment completion, perceptual identification, and general knowledge) and two explicit memory measures (graphemic cued recall and semantic cued recall). In Experiment 1, we demonstrated that increases in exposure time lead to increases in implicit perceptual memory, but not to implicit conceptual memory, when the encoding task focuses on perceptual features of the stimulus. We replicated this effect in Experiment 2 and demonstrated that increases in exposure time lead to increases in perceptualand conceptual memory when the measures are explicit. Thus, the current experiments demonstrate that manipulations of exposure time lead to dissociations in implicit, but not explicit, memory.     

The lifespan of time intervals in reference memory

To further explore how memory influences time judgments, we conducted two experiments on the lifespan of temporal representations in memory. Penney et al (2000, Journal of Experimental Psychology Human Perception and Performance 26 1770-1787) reported that the perceived duration of auditorily and visually marked intervals differs only when both marker-type intervals are compared directly. This finding can be explained by a 'memory-mixing' process, whereby the memory trace of previous intervals influences the perception of upcoming ones, which are then added to the memory content. In the experiments discussed here, we manipulated the mixing mode of auditory/visual signal presentations. In experiment 1, signals from the same modality were either grouped by blocks or randomised within blocks. The results showed that the auditory/visual difference decreased but remained present when modalities were grouped by blocks. In experiment 2, we used a line-segmentation task. The results showed that, after a training block was performed in one modality, the perceived duration of signals from the other modality was distorted for at least 30 trials and that the magnitude of the difference decreased as the block went on. The results of both experiments highlight the influence of memory on time judgments, providing empirical support to, and quantitative portrayal of, the memory-mixing process.     

Recognition time for information stored in long-term memory

Two experiments were performed to determine the effects of number of words in a target set (varying from 10 to 26) and the nature of distractor words on the latency of both positive and negative recognition responses. Before the test phase, S memorized a list of words and then was tested with a series of single words. To each presentation S made a positive or negative response to indicate whether or not the word was a member of the memorized target list. Response latency was observed to be an increasing function of memory list length. Negative response latency also was greater if distractor words were visually or semantically similar to specific target words. The results were analyzed in terms of a modified signal detection model. It is assumed that S makes a subjective judgment of the familiarity of a test item and on that basis decides either to respond immediately or to delay the response until a search of the memorized list can be executed. Several different models of the search process are considered and evaluated against latency measures and error data.     

Order information in short-term memory and time estimation

In previous experiments, the amount of interference between time production and visual or memory search tasks was shown not to be related to the level of difficulty of the search task per se, but instead to the amount of processing in short-term memory required in the search task. The first experiment of the present study verified whether the amount of interference between time production and a short-term memory task may be related to the level of difficulty of the short-term memory task. Two versions of a memory task, with and without processing of order information, were combined with a temporal interval production task in a concurrent processing condition. As is shown in a control reaction time task, processing order information increased the level of difficulty of the memory search task. In the concurrent processing condition, the interference between short-term memory processing and time production was stronger when the level of difficulty of the short-term memory search task was increased by requiring that order information be processed. The results of Experiment 2 showed that the amount of interference between a similar short-term memory task and time production seems not to be related to the amount of order information that must be maintained during the time production task. This dissociation between the effects of processing and the maintenance of order information is compatible with a similar dissociation, observed in previous experiments, between the effects of processing and those of maintaining item information in short-term memory on concurrent time production.     

Offline consolidation of memory varies with time in slow wave sleep and can be accelerated by cuing memory reactivations

Memory representations are reactivated during slow-wave sleep (SWS) after learning, and these reactivations cause a beneficial effect of sleep for memory consolidation. Memory reactivations can also be externally triggered during sleep by associated cues which enhance the sleep-dependent memory consolidation process. Here, we compared in humans the influence of sleep periods (i) of 40min and (ii) of 90min without externally triggered reactivations and (iii) of externally triggered reactivations by an associated odor cue during a 40-min sleep period on the consolidation of previously learned hippocampus-dependent visuo-spatial memories. We show that external reactivation by an odor cue during the 40-min sleep period enhanced memory stability to the same extent as 90min of sleep without odor reactivation. In contrast, 40min of sleep without external reactivations were not sufficient to benefit memory. In the 90-min sleep condition, memory enhancements were associated with time spent in SWS and were independent of the presence or absence of REM sleep. These results suggest that the efficacy of hippocampus-dependent memory consolidation depends on the duration of sleep and particularly SWS. External reactivation cues can accelerate the consolidation process even during shorter sleep episodes.     

Binding across space and time in visual working memory

Recent studies of visual short-term memory have suggested that the binding of features such as color and shape into remembered objects is relatively automatic. A series of seven experiments broadened this investigation by comparing the immediate retention of colored shapes with performance when color and shape were separated either spatially or temporally, with participants required actively to form the bound object. Attentional load was manipulated with a demanding concurrent task, and retention in working memory was then tested using a single recognition probe. Both spatial and temporal separation of features tended to impair performance, as did the concurrent task. There was, however, no evidence for greater attentional disruption of performance as a result of either spatial or temporal separation of features. Implications for the process of binding in visual working memory are discussed, and an interpretation is offered in terms of the episodic buffer component of working memory, which is assumed to be a passive store capable of holding bound objects, but not of performing the binding.     

工作记忆的存储时间及目标时距对时间知觉的影响

本研究操作记忆信息与计时开始之间的时间间隔（ISI）和目标时距,探讨工作记忆影响时间判断的灵活性。被试首先记忆一个客体,然后在每个trial的最后判断测试刺激是否与记忆项相同;在延迟阶段,被试完成时间判断任务,即判断相继出现的两个刺激的时距哪个更长（或更短）。时间任务中的一个刺激与记忆内容完全相同,相应的另一个刺激与记忆内容在形状和颜色上都不同。重复条件下,被试忽略第一个刺激,仅完成时间判断任务。结果发现,时间间隔（ISI）短时,记忆匹配条件下的准确率更高,匹配刺激延长了知觉的时间;但随着时间间隔的增加,工作记忆匹配对时间判断的影响降低甚至消失。并且,长或短ISI,记忆任务或重复条件下,目标时距长时,记忆匹配反而缩短了知觉的时间。研究说明工作记忆对时间判断的影响是灵活的,受到注意或工作记忆等高级认知系统的调控。     

The time course of consolidation in visual working memory

How long does it take to form a durable representation in visual working memory? Several theorists have proposed that this consolidation process is very slow. Here, we measured the time course of consolidation. Observers performed a change-detection task for colored squares, and shortly after the presentation of the first array, pattern masks were presented at the locations of each of the colored squares to disrupt representations that had not yet been consolidated. Performance on the memory task was impaired when the delay between the colored squares and the masks was short, and this effect became larger when the number of colored squares was increased. The rate of consolidation was approximately 50 ms per item, which is considerably faster than previous proposals.     

Hemispheric asymmetries in the time course of recognition memory

Hemispheric specialization has been studied extensively within subfields ranging from perception to language comprehension. However, the study of asymmetries for basic memory functions—an area that holds promise for bridging these low- and high-level cognitive domains—has been sporadic at best. We examined each hemisphere’s tendency to retain verbal information over time, using a continuous recognition memory task with lateralized study items and central test probes. We found that the ubiquitous advantage of the left hemisphere for the processing and retention of verbal information is attenuated and perhaps even reversed over long retention intervals. This result is consistent with theories that propose differences in the degree to which the hemispheres maintain veridical versus semantically transformed representations of the input they receive.     

On time, memory and dynamic form

A common approach to explaining the perception of form is through the use of static features. The weakness of this approach points naturally to dynamic definitions of form. Considering dynamical form, however, leads inevitably to the need to explain how events are perceived as time-extended--a problem with primacy over that even of qualia. Optic flow models, energy models, models reliant on a rigidity constraint are examined. The reliance of these models on the instantaneous specification of form at an instant, t, or across a series of such instants forces the consideration of the primary memory supporting both the perception of time-extended events and the time-extension of consciousness. This cannot be reduced to an integration over space and time. The difficulty of defining the basis for this memory is highlighted in considerations of dynamic form in relation to scales of time. Ultimately, the possibility is raised that psychology must follow physics in a more profound approach to time and motion.     

The time course of spatial memory distortions

Four experiments investigated the memory distortions for the location of a dot in relation to two horizontally aligned landmarks. In Experiment 1, participants reproduced from memory a dot location with respect to the two landmarks. Their performance showed a systematic pattern of distortion that was consistent across individual participants. The three subsequent experiments investigated the time course of spatial memory distortions. Using a visual discrimination task, we were able to map the emergence of spatial distortions within the first 800 msec of the retention interval. After retention intervals as brief as 50 msec, a distortion was already present. In all but one experiment, the distortion increased with longer retention intervals. This early onset of spatial memory distortions might reflect the almost immediate decay of detailed spatial information and the early influence of an enduring spatial memory representation, which encodes spatial information in terms of the perceived structure of space.