Stored Representations Research Articles

Implementation of a UK supermarket intervention to increase purchasing of fresh fruit and vegetables: process evaluation of the WRAPPED natural experiment

BackgroundPlacement interventions, characterised by greater availability and more prominent positioning of healthy food products in supermarkets and other food stores, are associated with healthier patterns of purchasing and diet. The WRAPPED intervention study is a natural experiment that aims to evaluate a supermarket placement intervention to improve fruit and vegetable sales, household purchasing and the dietary quality of women and their children. Process evaluation, alongside the evaluation of outcomes, is essential to understand how interventions are implemented, under what circumstances they are effective, and their mechanisms of impact. This study aimed to assess the implementation of the WRAPPED placement intervention.MethodsThe study adopted a convergent mixed-methods design. Quantitative data extracted from study store planograms (visual representation of stores and product placement) before and after intervention implementation were used to assess the positioning of fresh fruit and vegetables in the first aisle from the front entrance (intervention dose). The availability of fresh fruit and vegetables in each study store was examined from stock-keeping unit (SKU) figures before and after intervention implementation. An intervention implementation survey (IIS) completed with store managers and senior supervisors before and 1- and 6-months post-intervention implementation enabled examination of the context across study stores. Semi-structured interviews with store managers and senior supervisors provided qualitative data about store staff experiences and perceptions of the intervention between 6-months post-intervention implementation.ResultsThe placement intervention was implemented with close adherence to the study protocol. There were marked differences, post-intervention implementation, in the positioning of fresh fruit and vegetables in intervention stores compared with control stores: median distance in intervention stores was 8.0 m (IQR 5.0 to 10.0) compared with 23.8 m (IQR 21.0 to 30.0) in control stores (P < 0.0001). The availability of varieties of fresh fruit and vegetables increased in intervention stores post-intervention compared with control stores: median (IQR) among intervention stores was 72 (51, 84) compared with 56.5 (50, 62) in control stores (P = 0.03). The mean change from baseline to post-implementation in number of different fruit and vegetables available in intervention stores was 15.3 (SD 16.7) (P = 0.01). IIS and interview data demonstrated little difference between intervention and store contexts over time. Reinforcing factors for intervention implementation included: head-office leadership, store staff views and attitudes and increased awareness of the importance of offering healthy food in prominent locations within stores.ConclusionThis study demonstrated that placement interventions which promote fresh fruit and vegetables to customers in discount supermarkets can be implemented effectively. These findings are encouraging for the implementation of national food policies which modify retail environments to improve population purchasing and dietary patterns.Trial registrationNCT03573973; Pre-results.

Unravelling the object-based nature of visual working memory: insight from pointers.

Visual working memory (VWM) plays a crucial role in temporarily storing and processing visual information, but the nature of stored representations and their interaction with new inputs has long been unclear. The pointer system refers to how VWM links new sensory inputs to stored information using specific cues. This study aimed to investigate whether the pointer system is based on spatial, feature-based, or object-based cues by employing the repetition benefit effect, where memory performance improves with repeated memory items. Across three experiments, we manipulated spatial positions, shapes, and colors as pointer cues to determine how these features affect VWM consolidation and updating. The results showed that while spatial location serves as a strong pointer cue, shape and color features can also effectively reestablish object correspondence in VWM. These findings support the view that the pointer system in VWM is flexible and object-based, utilizing various feature cues to maintain memory continuity. This study provides new insights into how VWM connects new inputs with stored information through the pointer system.

Memory representations during slow change blindness.

Classic change blindness is the phenomenon where seemingly obvious changes that coincide with visual disruptions (such as blinks or brief blanks) go unnoticed by an attentive observer. Some early work into the causes of classic change blindness suggested that any pre-change stimulus representation is overwritten by a representation of the altered post-change stimulus, preventing change detection. However, recent work revealed that, even when observers do maintain memory representations of both the pre- and post-change stimulus states, they can still miss the change, suggesting that change blindness can also arise from a failure to compare the stored representations. Here, we studied slow change blindness, a related phenomenon that occurs even in the absence of visual disruptions when the change occurs sufficiently slowly, to determine whether it could be explained by conclusions from classic change blindness. Across three different slow change blindness experiments we found that observers who consistently failed to notice the change had access to at least two memory representations of the changing display. One representation was precise but short lived: a detailed representation of the more recent stimulus states, but fragile. The other representation lasted longer but was fairly general: stable but too coarse to differentiate the various stages of the change. These findings suggest that, although multiple representations are formed, the failure to compare hypotheses might not explain slow change blindness; even if a comparison were made, the representations would be too sparse (longer term stores) or too fragile (short-lived stores) for such comparison to inform about the change.

Top-Down Task Goals Induce the Retrieval State.

Engaging the retrieval state (Tulving, 1983) impacts processing and behavior (Long and Kuhl, 2019, 2021; Smith et al., 2022), but the extent to which top-down factors-explicit instructions and goals-versus bottom-up factors-stimulus properties such as repetition and similarity-jointly or independently induce the retrieval state is unclear. Identifying the impact of bottom-up and top-down factors on retrieval state engagement is critical for understanding how control of task-relevant versus task-irrelevant brain states influence cognition. We conducted between-subjects recognition memory tasks on male and female human participants in which we varied test phase goals. We recorded scalp electroencephalography and used an independently validated mnemonic state classifier (Long, 2023) to measure retrieval state engagement as a function of top-down task goals (recognize old vs detect new items) and bottom-up stimulus repetition (hits vs correct rejections (CRs)). We find that whereas the retrieval state is engaged for hits regardless of top-down goals, the retrieval state is only engaged during CRs when the top-down goal is to recognize old items. Furthermore, retrieval state engagement is greater for low compared to high confidence hits when the task goal is to recognize old items. Together, these results suggest that top-down demands to recognize old items induce the retrieval state independent from bottom-up factors, potentially reflecting the recruitment of internal attention to enable access of a stored representation.

The Equations for Consciousness: A Reply to “Tracking the Travels,” a Review of Journey of the Mind

The Equations for Consciousness: A Reply to “Tracking the Travels,” a Review of <i>Journey of the Mind</i>

Modelling representations in speech normalization of prosodic cues

The lack of invariance problem in speech perception refers to a fundamental problem of how listeners deal with differences of speech sounds produced by various speakers. The current study is the first to test the contributions of mentally stored distributional information in normalization of prosodic cues. This study starts out by modelling distributions of acoustic cues from a speech corpus. We proceeded to conduct three experiments using both naturally produced lexical tones with estimated distributions and manipulated lexical tones with f0 values generated from simulated distributions. State of the art statistical techniques have been used to examine the effects of distribution parameters in normalization and identification curves with respect to each parameter. Based on the significant effects of distribution parameters, we proposed a probabilistic parametric representation (PPR), integrating knowledge from previously established distributions of speakers with their indexical information. PPR is still accessed during speech perception even when contextual information is present. We also discussed the procedure of normalization of speech signals produced by unfamiliar talker with and without contexts and the access of long-term stored representations.

3 x Phonology

AbstractWhat does it take to run a full substance-free phonology (SFP)? Because in classical approaches only items below the skeleton have phonetic properties that, according to SFP, need to be expunged, current work in SFP only ever concerns segmental aspects. If substance is removed from segmental representation and primes and computation are therefore arbitrary, the non-trivial question arises: how can such a system communicate with a system where primes and computation are not arbitrary (at and above the skeleton)? The two phonologies below and at / above the skeleton that exist in production are complemented with a third phonology that occurs upon lexicalization, that is, when L1 learners or adults transform the acoustic signal into a stored representation. The core of this article argues that this broad architecture is inhabited by three distinct computational systems along the classical feature geometric divisions: Son(ority) is located at and above the skeleton, while Place and Lar(yngeal) live below the skeleton. The question then is how a multiple-module spell-out works, that is, how ingredients from three distinct vocabularies can be mapped onto a single phonetic item. It is argued that the skeleton plays a central role in this conversion.

Specificity of phonological representations in school-age high-functioning ASD children

Purpose: Well-specified phonological representations are important for the development of spoken and written language. This study investigates the types of speech errors and the quality of phonological representations in Greek-speaking school-age children with high-functioning autism spectrum disorder (HF-ASD), as well as the relationship between stored phonological representations and speech output in this sample, according to Stackhouse and Wells’ (1997) model. Method: All participants completed a phonological and a naming test, and a non-word repetition task. A receptive phonological task was administered to a subgroup of HF-ASD and typically developing (TD) participants. According to performance in the phonological test, the HF-ASD children were categorised as ASD with Speech Sound Disorder (SSD) or ASD without SSD. Result: The HF-ASD children made significantly more speech errors and showed significant difficulties in the repetition of non-words and the stored phonological representations compared to the TD group but had the same naming abilities with their TD peers. The ASD children with SSD and without SSD performed alike in the receptive task, indicating that both groups had unspecified phonological representations. Conclusion: These results support the hypothesis of distinct phonological representations for speech input and output and highlight the need of using receptive tasks to evaluate underlying phonological knowledge, a process which could allow clinicians to identify the level of speech breakdown.

The sense of body ownership shapes the visual representation of body size.

The conscious body image includes the visual representation of body-parts size; whether this component of body perception can flexibly adapt to changes of the sense of ownership of one's body-parts remains to be demonstrated. The present study addresses this issue, showing that the ownership of a novel hand affects the conscious visual perception of the size of the really owned hand. Through a series of experiments in healthy adults, we assess how the embodiment of fake hands of different sizes (i.e., Rubber Hand Illusion, RHI) affects visual size estimation of the own hand. Our results demonstrate that the embodiment of a fake hand bigger in size than the own hand (Experiment 1), but not of a smaller fake hand (Experiment 2), affects the perception of similarity in size between the own hand and a visual model of the own hand, with a tendency toward an overestimation of the size of the hand exposed to the RHI (Experiment 1). The illusory ownership of a bigger hand does not affect the visual estimate of object size (Experiment 3). These findings show the tight link between the body image and the sense of ownership, the latter being able to change stored representations of body-parts size. This evidence might pave the way for restoring pathological alteration of body image through strategies accessing the body schema. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

A Variable Clock Underlies Internally Generated Hippocampal Sequences.

Humans have the ability to store and retrieve memories with various degrees of specificity, and recent advances in reinforcement learning have identified benefits to learning when past experience is represented at different levels of temporal abstraction. How this flexibility might be implemented in the brain remains unclear. We analyzed the temporal organization of male rat hippocampal population spiking to identify potential substrates for temporally flexible representations. We examined activity both during locomotion and during memory-associated population events known as sharp-wave ripples (SWRs). We found that spiking during SWRs is rhythmically organized with higher event-to-event variability than spiking during locomotion-associated population events. Decoding analyses using clusterless methods further indicate that a similar spatial experience can be replayed in multiple SWRs, each time with a different rhythmic structure whose periodicity is sampled from a log-normal distribution. This variability increases with experience despite the decline in SWR rates that occurs as environments become more familiar. We hypothesize that the variability in temporal organization of hippocampal spiking provides a mechanism for storing experiences with various degrees of specificity.SIGNIFICANCE STATEMENT One of the most remarkable properties of memory is its flexibility: the brain can retrieve stored representations at varying levels of detail where, for example, we can begin with a memory of an entire extended event and then zoom in on a particular episode. The neural mechanisms that support this flexibility are not understood. Here we show that hippocampal sharp-wave ripples, which mark the times of memory replay and are important for memory storage, have a highly variable temporal structure that is well suited to support the storage of memories at different levels of detail.

A biophysical counting mechanism for keeping time.

The ability to estimate and produce appropriately timed responses is central to many behaviors including speaking, dancing, and playing a musical instrument. A classical framework for estimating or producing a time interval is the pacemaker-accumulator model in which pulses of a pacemaker are counted and compared to a stored representation. However, the neural mechanisms for how these pulses are counted remain an open question. The presence of noise and stochasticity further complicates the picture. We present a biophysical model of how to keep count of a pacemaker in the presence of various forms of stochasticity using a system of bistable Wilson-Cowan units asymmetrically connected in a one-dimensional array; all units receive the same input pulses from a central clock but only one unit is active at any point in time. With each pulse from the clock, the position of the activated unit changes thereby encoding the total number of pulses emitted by the clock. This neural architecture maps the counting problem into the spatial domain, which in turn translates count to a time estimate. We further extend the model to a hierarchical structure to be able to robustly achieve higher counts.

The development of template-based facial expression perception from 6 to 15 years of age.

When perceiving emotional facial expressions, adults use a template-matching strategy, comparing the perceived face with a stored representation. A rejection of unnaturally exaggerated faces is characteristic of this strategy because the exaggerated expressions do not match the stored template. In contrast, a rule-based perceptual strategy (e.g., wide eyes indicate surprise) would be more tolerant of exaggeration. The current study uses exaggeration tolerance to test the expression perception strategies of children from 6 to 15 years of age. In Experiment 1, 62 (38 male) participants viewed pairs of happy or sad faces varying in exaggeration and selected the face that looked closest to how a happy (or sad) person really looks. With age, children became less likely to choose the more exaggerated expression. In Experiment 2, this result was replicated with each of the six basic emotions. Sixty-six children (26 male, 50 Caucasian, 10 mixed-race, four Indian, two unidentified) from 6 to 15 years of age completed the same experimental tasks as Experiment 1 for all six emotions. Again, with age children became less likely to choose the more exaggerated face. The results from both experiments suggest that the development of an adult-like template-matching strategy lasts into adolescence. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Eye-hand coordination: memory-guided grasping during obstacle avoidance.

When reaching to grasp previously seen, now out-of-view objects, we rely on stored perceptual representations to guide our actions, likely encoded by the ventral visual stream. So-called memory-guided actions are numerous in daily life, for instance, as we reach to grasp a coffee cup hidden behind our morning newspaper. Little research has examined obstacle avoidance during memory-guided grasping, though it is possible obstacles with increased perceptual salience will provoke exacerbated avoidance maneuvers, like exaggerated deviations in eye and hand position away from obtrusive obstacles. We examined the obstacle avoidance strategies adopted as subjects reached to grasp a 3D target object under visually-guided (closed loop or open loop with full vision prior to movement onset) and memory-guided (short- or long-delay) conditions. On any given trial, subjects reached between a pair of flanker obstacles to grasp a target object. The positions and widths of the obstacles were manipulated, though their inner edges remained a constant distance apart. While reach and grasp behavior was consistent with the obstacle avoidance literature, in that reach, grasp, and gaze positions were biased away from obstacles most obtrusive to the reaching hand, our results reveal distinctive avoidance approaches undertaken depend on the availability of visual feedback. Contrary to expectation, we found subjects reaching to grasp after a long delay in the absence of visual feedback failed to modify their final fixation and grasp positions to accommodate the different positions of obstacles, demonstrating a more moderate, rather than exaggerative, obstacle avoidance strategy.

The spontaneous location recognition task for assessing spatial pattern separation and memory across a delay in rats and mice.

Keeping similar memories distinct from one another is a critical cognitive process without which we would have difficulty functioning in everyday life. Memories are thought to be kept distinct through the computational mechanism of pattern separation, which reduces overlap between similar input patterns to amplify differences among stored representations. At the behavioral level, impaired pattern separation has been shown to contribute to memory deficits seen in neuropsychiatric and neurodegenerative diseases, including Alzheimer's disease, and in normal aging. This protocol describes the use of the spontaneous location recognition (SLR) task in mice and rats to behaviorally assess spatial pattern separation ability. This two-phase spontaneous memory task assesses the extent to which animals can discriminate and remember object locations presented during the encoding phase. Using three configurations of the task, the similarity of the to-be-remembered locations can be parametrically manipulated by altering the spatial positions of objects-dissimilar, similar or extra similar-to vary the load on pattern separation. Unlike other pattern separation tasks, SLR varies the load on pattern separation during encoding, when pattern separation is thought to occur. Furthermore, SLR can be used in standard rodent behavioral facilities with basic expertise in rodent handling. The entire protocol takes ~20 d from habituation to testing of the animals on all three task configurations. By incorporating breaks between testing, and varying the objects used as landmarks, animals can be tested repeatedly, increasing experimental power by allowing for within-subjects manipulations.

Distributed associative memory network with memory refreshing loss

Despite recent progress in memory augmented neural network (MANN) research, associative memory networks with a single external memory still show limited performance on complex relational reasoning tasks. Especially the content-based addressable memory networks often fail to encode input data into rich enough representation for relational reasoning and this limits the relation modeling performance of MANN for long temporal sequence data. To address these problems, here we introduce a novel Distributed Associative Memory architecture (DAM) with Memory Refreshing Loss (MRL) which enhances the relation reasoning performance of MANN. Inspired by how the human brain works, our framework encodes data with distributed representation across multiple memory blocks and repeatedly refreshes the contents for enhanced memorization similar to the rehearsal process of the brain. For this procedure, we replace a single external memory with a set of multiple smaller associative memory blocks and update these sub-memory blocks simultaneously and independently for the distributed representation of input data. Moreover, we propose MRL which assists a task’s target objective while learning relational information existing in data. MRL enables MANN to reinforce an association between input data and task objective by reproducing stochastically sampled input data from stored memory contents. With this procedure, MANN further enriches the stored representations with relational information. In experiments, we apply our approaches to Differential Neural Computer (DNC), which is one of the representative content-based addressing memory models and achieves the state-of-the-art performance on both memorization and relational reasoning tasks.

Statistical learning of target selection and distractor suppression shape attentional priority according to different timeframes

Recent findings suggest that attentional and oculomotor control is heavily affected by past experience, giving rise to selection and suppression history effects, so that target selection is facilitated if they appear at frequently attended locations, and distractor filtering is facilitated at frequently ignored locations. While selection history effects once instantiated seem to be long-lasting, whether suppression history is similarly durable is still debated. We assessed the permanence of these effects in a unique experimental setting investigating eye-movements, where the locations associated with statistical unbalances were exclusively linked with either target selection or distractor suppression. Experiment 1 and 2 explored the survival of suppression history in the long and in the short term, respectively, revealing that its lingering traces are relatively short lived. Experiment 3 showed that in the very same experimental context, selection history effects were long lasting. These results seem to suggest that different mechanisms support the learning-induced plasticity triggered by selection and suppression history. Specifically, while selection history may depend on lasting changes within stored representations of the visual space, suppression history effects hinge instead on a functional plasticity which is transient in nature, and involves spatial representations which are constantly updated and adaptively sustain ongoing oculomotor control.

The strength of morphophonological schemas: Consonant mutations in Polish

Selective elimination of consonant mutations in Polish provides evidence supporting construction-based sublexicons and morphophonological schemas extracted from them. Morphophonological schemas exhibit various strength depending on their type frequency, they refer to morpheme-specific classes of segments and their impact is continuously mediated by paradigm uniformity pressures. A low-frequency and a highfrequency pattern are analyzed: agent nouns in -ist-a/-yst-a and diminutives in -ek. Two kinds of frequency are important predictors of pattern modification: type frequency and token frequency. As for the impact of type frequency, the less frequent a pattern is in the lexicon, the more susceptible it is to modifications promoted by paradigm uniformity. Schemas are ranked based on the type frequency of the morphological patterns they encode and interact with paradigm uniformity constraints. Schemas representing less frequent patterns are outranked by paradigm uniformity constraints and are thus more likely to be modified than those representing more frequent patterns. Regarding token frequency, the greater stability of high-frequency words than comparable low-frequency words is linked to their strong representations and a constraint promoting the use of stored representations. The continuous effect of paradigm uniformity effects gets support from the results of a nonce-word experiment.

Sensing and seeing associated with overlapping occipitoparietal activation in simultaneous EEG-fMRI.

The presence of a change in a visual scene can influence brain activity and behavior, even in the absence of full conscious report. It may be possible for us to sense that such a change has occurred, even if we cannot specify exactly where or what it was. Despite existing evidence from electroencephalogram (EEG) and eye-tracking data, it is still unclear how this partial level of awareness relates to functional magnetic resonance imaging (fMRI) blood oxygen level dependent (BOLD) activation. Using EEG, fMRI, and a change blindness paradigm, we found multi-modal evidence to suggest that sensing a change is distinguishable from being blind to it. Specifically, trials during which participants could detect the presence of a colour change but not identify the location of the change (sense trials), were compared to those where participants could both detect and localise the change (localise or see trials), as well as change blind trials. In EEG, late parietal positivity and N2 amplitudes were larger for localised changes only, when compared to change blindness. However, ERP-informed fMRI analysis found no voxels with activation that significantly co-varied with fluctuations in single-trial late positivity amplitudes. In fMRI, a range of visual (BA17,18), parietal (BA7,40), and mid-brain (anterior cingulate, BA24) areas showed increased fMRI BOLD activation when a change was sensed, compared to change blindness. These visual and parietal areas are commonly implicated as the storage sites of visual working memory, and we therefore argue that sensing may not be explained by a lack of stored representation of the visual display. Both seeing and sensing a change were associated with an overlapping occipitoparietal network of activation when compared to blind trials, suggesting that the quality of the visual representation, rather than the lack of one, may result in partial awareness during the change blindness paradigm.

How the unconscious mind controls body movements: Body schema distortion in anorexia nervosa.

Besides all visible somatic manifestations, distorted body representation is a key symptom for anorexia nervosa (AN). Body representation can be divided into a conscious component, body image, and an unconscious action-related one, body schema. As behavioral studies already explored the impact of a distorted body image in AN, we aimed to explore whether distortion also extends into unconscious body schema. This study is the first with an unbiased measurement of the body schema in a homogeneous sample of AN patients. Twenty-three patients diagnosed with AN and 23 healthy controls (HC) walked through a door like aperture varying in width. Door width was based on participants shoulder width and ranged from an aperture-to-shoulder-ratio of (A/S) 0.9 to 1.45. Shoulder rotation was measured as indication of perceived body width. To measure the unconscious body schema, we used a cover story pretending to investigate the influence of change of position on retention memory. We found a significantly higher critical A/S for AN than HC, which indicates that AN patients rotate their shoulders for relatively larger door widths than HC, thus unconsciously estimating their body size to be larger than in reality. Additionally, we found a correlation between negative body attribution and overestimation of bodily dimensions. As stated by the "allocentric-lock"-hypothesis, AN patients might be locked to a stored representation of their body that cannot be updated and remains at pre-AN conditions. We suggest future AN-therapy to counter body schema alterations by combining cognitive behavioral therapy and virtual reality therapy.

Development of Persian Lexical Neighborhood Tests

IntroductionSpoken word recognition (SWR) is a complicated process whereby through listening to a word or sentence we automatically connect each word's acoustic signal to its stored representations in the mental lexicon. We hypothesized that the children's performance on SWR would be influenced by the lexical difficulty and word length. The aim of the study was to develop the Persian Lexical Neighborhood Tests (PLNTs) as a lexically controlled toolkit based on the Neighborhood Activation Model to measure the SWR of Persian-speaking children. MethodsThe research project was carried out in two phases (Weber and Scharenborg, 2012) [1]: development of the PLNTs (Luce and Pisoni, 1998) [2]; Using PLNTs in children with normal hearing. In Phase 1, to determine the lexical difficulty of words (easy, hard, and neutral), we calculated word frequencies and neighborhood densities for the words elicited from the 461 well documented language samples of Persian-speaking children aged 2–5 years old. Accordingly, four lexically controlled words subscales were generated by selecting appropriately easy and hard key words include: Persian Monosyllabic Lexical Neighborhood Test (PMLNT)-easy, PMLNT-hard, Persian Disyllabic Lexical Neighborhood Test (PDLNT)-easy, and PDLNT -hard. In Phase 2, The PLNTs were performed by sound field at different levels of signal to noise ratio (SNR) on twenty children with normal hearing between the ages of 6–12 year. ResultsThe participants performed significantly better on SWR using the PLNTs consisting of easy words compared to the PLNTs consisting of hard words and using disyllabic words compared to monosyllabic words. Moreover, the participants’ performance on SWR improved overall with increasing the SNR levels. ConclusionThe PLNTs is a lexically controlled assessment toolkit independent of vocabulary and language competency that can be used to measure the SWR performance in Persian-speaking children under spectrally degraded conditions.