Short-term memory for spatial, sequential and duration information

Space and time appear to play key roles in the way that information is organized in short-term memory (STM). Some argue that they are crucial contexts within which other stored features are embedded, allowing binding of information that belongs together within STM. Here we review recent behavioral, neurophysiological and imaging studies that have sought to investigate the nature of spatial, sequential and duration representations in STM, and how these might break down in disease. Findings from these studies point to an important role of the hippocampus and other medial temporal lobe structures in aspects of STM, challenging conventional accounts of involvement of these regions in only long-term memory

Is a Picture Worth a Thousand Words? Congruency Between Encoding and Testing Improves Detection of Concealed Memories

The current study addressed modality effects in a web-based Concealed Information Test (CIT) by asking participants to encode, and later conceal, crime-related details. Items were encoded and tested verbally or pictorially. A pilot (N = 73) and a preregistered study (N = 158) showed a robust interaction between encoding and testing modality: Items that were encoded and tested in the same modality were associated with better detection. Moreover, recognition of verbally encoded items could not be detected in a pictorial test. Our findings support the existence of a modality-congruency effect when subjects try to conceal their knowledge. In applied scenarios, the modality of test items should be matched to the modality in which crime-related details were encoded. Furthermore, a pictorial CIT might protect informed innocents if leakage happened verbally

Spatial constancy of attention across eye movements is mediated by the presence of visual objects

Recent studies have shown that attentional facilitation lingers at the retinotopic coordinates of a previously attended position after an eye movement. These results are intriguing, because the retinotopic location becomes behaviorally irrelevant once the eyes have moved. Critically, in these studies participants were asked to maintain attention on a blank location of the screen. In the present study, we examined whether the continuing presence of a visual object at the cued location could affect the allocation of attention across eye movements. We used a trans-saccadic cueing paradigm in which the relevant positions could be defined or not by visual objects (simple square outlines). We find an attentional benefit at the spatiotopic location of the cue only when the object (the placeholder) has been continuously present at that location. We conclude that the presence of an object at the attended location is a critical factor for the maintenance of spatial constancy of attention across eye movements, a finding that helps to reconcile previous conflicting results

Classic and recent advances in understanding amnesia

Neurological amnesia has been and remains the focus of intense study, motivated by the drive to understand typical and atypical memory function and the underlying brain basis that is involved. There is now a consensus that amnesia associated with hippocampal (and, in many cases, broader medial temporal lobe) damage results in deficits in episodic memory, delayed recall, and recollective experience. However, debate continues regarding the patterns of preservation and impairment across a range of abilities, including semantic memory and learning, delayed recognition, working memory, and imagination. This brief review highlights some of the influential and recent advances in these debates and what they may tell us about the amnesic condition and hippocampal function

An eye-movement study of relational memory in adults with Autism Spectrum Disorder

Persons with Autism Spectrum Disorder (ASD) demonstrate good memory for single items but difficulties remembering contextual information related to these items. Recently, we found compromised explicit but intact implicit retrieval of object-location information in ASD (Ring et al. 2015). Eye-movement data collected from a sub-sample of the participants are the focus of the current paper. At encoding, trial-by-trial viewing durations predicted subsequent retrieval success only in typically developing (TD) participants. During retrieval, TD compared to ASD participants looked significantly longer at previously studied objectlocations compared to alternative locations. These findings extend similar observations recently reported by Cooper et al. (2017a) and demonstrate that eye-movement data can shed important light on the source and nature of relational memory difficulties in ASD

Something from (almost) nothing: Buildup of object memory from forgettable single fixations

We can recognize thousands of individual objects in scores of familiar settings, and yet we see most of them only through occasional glances that are quickly forgotten. How do we come to recognize any of these objects? Here, we show that when objects are presented intermittently for durations of single fixations, the originally fleeting memories become gradually stabilized, such that, after just eight separated fixations, recognition memory after half an hour is as good as during an immediate memory test. However, with still shorter presentation durations, memories take more exposures to stabilize. Our results thus suggest that repeated glances suffice to remember the objects of our environment

Suppression-induced forgetting:a pre-registered replication of the think/no-think paradigm

Post-traumatic stress disorder is characterised by recurring memories of a traumatic experience despite deliberate attempts to forget (i.e., suppression). The Think/No-Think (TNT) task has been used widely in the laboratory to study suppression-induced forgetting. During the task, participants learn a series of cue-target word pairs. Subsequently, they are presented with a subset of the cue words and are instructed to think (respond items) or not think about the corresponding target (suppression items). Baseline items are not shown during this phase. Successful suppression-induced forgetting is indicated by the reduced recall of suppression compared to baseline items in recall tests using either the same or different cues than originally studied (i.e., same- and independent-probe tests, respectively). The current replication was a pre-registered collaborative effort to evaluate an online experimenter-present version of the paradigm in 150 English-speaking healthy individuals (89 females; MAge = 31.14, SDAge = 7.73). Overall, we did not replicate the suppression-induced forgetting effect (same-probe: BF01 = 7.84; d = 0.03 [95% CI: −0.13; 0.20]; independent-probe: BF01 = 5.71; d = 0.06 [95% CI: −0.12; 0.24]). These null results should be considered in light of our online implementation of the paradigm. Nevertheless, our findings call into question the robustness of suppression-induced forgetting

The Rapid Forgetting of Faces

How are faces forgotten? Studies examining forgetting in visual working memory (VWM) typically use simple visual features; however, in ecological scenarios, VWM typically contains complex objects. Given their significance in everyday functioning and their visual complexity, here we investigated how upright and inverted faces are forgotten within a few seconds, focusing on the raw errors that accompany such forgetting and examining their characteristics. In three experiments we found that longer retention intervals increased the size of errors. This effect was mainly accounted for by a larger proportion of random errors - suggesting that forgetting of faces reflects decreased accessibility of the memory representations over time. On the other hand, longer retention intervals did not modulate the precision of recall – suggesting that forgetting does not affect the precision of accessible memory representation. Thus, when upright and inverted faces are forgotten there is a complete failure to access them or a complete collapse of their memory representation. In contrast to the effect of retention interval (i.e., forgetting), face inversion led to larger errors that were mainly associated with decreased precision of recall. This effect was not modulated by the duration of the retention interval, and was observed even when memory was not required in the task. Therefore, upright faces are remembered more precisely compared to inverted ones due to perceptual, rather than mnemonic processes

The reference frame for encoding and retention of motion depends on stimulus set size

YesThe goal of this study was to investigate the reference frames used in perceptual encoding and storage of visual motion information. In our experiments, observers viewed multiple moving objects and reported the direction of motion of a randomly selected item. Using a vector-decomposition technique, we computed performance during smooth pursuit with respect to a spatiotopic (nonretinotopic) and to a retinotopic component and compared them with performance during fixation, which served as the baseline. For the stimulus encoding stage, which precedes memory, we found that the reference frame depends on the stimulus set size. For a single moving target, the spatiotopic reference frame had the most significant contribution with some additional contribution from the retinotopic reference frame. When the number of items increased (Set Sizes 3 to 7), the spatiotopic reference frame was able to account for the performance. Finally, when the number of items became larger than 7, the distinction between reference frames vanished. We interpret this finding as a switch to a more abstract nonmetric encoding of motion direction. We found that the retinotopic reference frame was not used in memory. Taken together with other studies, our results suggest that, whereas a retinotopic reference frame may be employed for controlling eye movements, perception and memory use primarily nonretinotopic reference frames. Furthermore, the use of nonretinotopic reference frames appears to be capacity limited. In the case of complex stimuli, the visual system may use perceptual grouping in order to simplify the complexity of stimuli or resort to a nonmetric abstract coding of motion information