Usage of semantic representations in recognition memory

Meanings of words facilitate false acceptance as well as correct rejection of lures in recognition memory tests, depending on the experimental context. This suggests that semantic representations are both directly and indirectly (i.e., mediated by perceptual representations) used in remembering. Studies using memory conjunction errors (MCEs) paradigms, in which the lures consist of component parts of studied words, have reported semantic facilitation of rejection of the lures. However, attending to components of the lures could potentially cause this. Therefore, we investigated whether semantic overlap of lures facilitates MCEs using Japanese Kanji words in which a whole-word image is more concerned in reading. Experiments demonstrated semantic facilitation of MCEs in a delayed recognition test (Experiment 1), and in immediate recognition tests in which participants were prevented from using phonological or orthographic representations (Experiment 2), and the salient effect on individuals with high semantic memory capacities (Experiment 3). Additionally, analysis of the receiver operating characteristic suggested that this effect is attributed to familiarity-based memory judgement and phantom recollection. These findings indicate that semantic representations can be directly used in remembering, even when perceptual representations of studied words are available.     

Unique contribution of semantic representations to immediate memory: an individual-differences approach

Studies have reported dissociations between the contributions of semantic and phonological representations to immediate remembering, found through experimental manipulations as well as specific clinical cases. Also, some studies based on the analysis of individual differences reported that a semantic cued recall task has a variance unshared with the immediate memory tasks which tap the contribution of phonological representations. However, another study suggested that cued recall performance could reflect a wider ability to cluster information by category. Furthermore, no studies of individual differences have investigated the unique semantic contribution in the visual domain. Therefore, the present study used specific immediate recognition memory tasks that have been used to investigate the semantic contribution in the verbal and visual domains. The results demonstrate the unshared variance that reflects the semantic contribution in both the verbal and the visual domain, and some commonality in these variances across the domains.     

Switching memory perspective

The perspective in which memories were spontaneously recalled, field (original perspective) or observer (see oneself in the memory), was examined for both recent and remote memories. Recent memories were dominated by field perspective whilst remote memories were dominated by observer perspective. Further, field memories contained reliably more episodic detail than observer memories. After a 1-week interval, the same memories were recalled again but with a switched memory perspective. Switching from an observer to a field perspective did not reliably increase the amount of episodic details in a memory. Switching from field to observer perspective did, however, reliably reduce the number of episodic details. These findings suggest that memories may be represented in long-term memory with a fixed perspective, either field or observer, which can be temporarily altered sometimes changing the nature of a memory, i.e. how much detail remains accessible.     

Factors influencing infants’ ability to update object representations in memory

Remembering persisting objects over occlusion is critical to representing a stable environment. Infants remember hidden objects at multiple locations and can update their representation of a hidden array when an object is added or subtracted. However, the factors influencing these updating abilities have received little systematic exploration. Here we examined the flexibility of infants’ ability to update object representations. We tested 11-month-olds in a looking-time task in which objects were added to or subtracted from two hidden arrays. Across five experiments, infants successfully updated their representations of hidden arrays when the updating occurred successively at one array before beginning at the other. But when updating required alternating between two arrays, infants failed. However, simply connecting the two arrays with a thin strip of foam-core led infants to succeed. Our results suggest that infants’ construal of an event strongly affects their ability to update memory representations of hidden objects. When construing an event as containing multiple updates to the same array, infants succeed, but when construing the event as requiring the revisiting and updating of previously attended arrays, infants fail.     

Media representations of environmental issues: From scientific to political discourse

IntroductionThe media is considered to be a social agent that intervenes in the elaboration of social representations of environmental issues.ObjectiveThis research analyses media representations of environmental issues and how they have been constructed and transformed from the Rio Summit in 1992 to 2006. The authors adopted a constructionist approach based on the theory of social representations (Moscovici, 1961/1976) to describe the generation of information by the mass media.MethodA sample of 1039 news articles from two Spanish newspapers (La Vanguardia and El País) was analysed. The period of study ranged from the Rio Earth Summit to several years after the Johannesburg Summit (1992–2006), and the study analyses both the content and form of the environmental news.ResultsThis longitudinal study shows not only an increase in environmental news during the period of analysis but also an increased variety of themes addressed and represented. The results evidence significant urban problems in recent years. The environment has shifted from being associated with nature to being predominately associated with the urban environment.ConclusionThe results suggest that there has been a movement from scientific to political discourse and a change towards greater reflection and social recognition of the relevance of environmental issues.     

Verbal cues flexibly transform spatial representations in human memory

ABSTRACT

Humans possess a unique ability to communicate spatially-relevant information, yet the intersection between language and navigation remains largely unexplored. One possibility is that verbal cues accentuate heuristics useful for coding spatial layouts, yet this idea remains largely untested. We test the idea that verbal cues flexibly accentuate the coding of heuristics to remember spatial layouts via spatial boundaries or landmarks. The alternative hypothesis instead conceives of encoding during navigation as a step-wise process involving binding lower-level features, and thus subsequently formed spatial representations should not be modified by verbal cues. Across three experiments, we found that verbal cues significantly affected pointing error patterns at axes that were aligned with the verbally cued heuristic, suggesting that verbal cues influenced the heuristics employed to remember object positions. Further analyses suggested evidence for a hybrid model, in which boundaries were encoded more obligatorily than landmarks, but both were accessed flexibly with verbal instruction. These findings could not be accounted for by a tendency to spend more time facing the instructed component during navigation, ruling out an attentional-encoding mechanism. Our findings argue that verbal cues influence the heuristics employed to code environments, suggesting a mechanism for how humans use language to communicate navigationally-relevant information.     

Interacting with objects compresses environmental representations in spatial memory

People perceive individual objects as being closer when they have the ability to interact with the objects than when they do not. We asked how interaction with multiple objects impacts representations of the environment. Participants studied multiple-object layouts, by manually exploring or simply observing each object, and then drew a scaled version of the environment (Exp. 1) or reconstructed a copy of the environment and its boundaries (Exp. 2) from memory. The participants who interacted with multiple objects remembered these objects as being closer together and reconstructed smaller environment boundaries than did the participants who looked without touching. These findings provide evidence that action-based perceptual distortions endure in memory over a moving observer’s multiple interactions, compressing not only representations between touched objects, but also untouched environmental boundaries.     

任务转换中惯性激活对内隐记忆的影响：来自ERPs的证据

以往研究认为内隐记忆具有不受干扰影响的自动化加工特征,其证据主要来自于对内隐记忆编码过程的研究。最近已有多项研究发现,内隐记忆受提取过程中的干扰影响,但对这一现象的产生机制目前仍尚无定论。本研究根据任务转换相关理论,通过将go/no-go范式引入干扰任务,探讨提取过程中前置干扰对内隐记忆产生影响的内在机制。结果表明,前置的干扰任务产生惯性激活时,后续的内隐记忆任务会受到影响,即启动效应降低。对惯性激活进行抑制后,随后的内隐记忆则不受影响。并且,在内隐记忆相关的N400成分上得到了与行为数据一致的结果,即在no-go干扰下,获得的N400新旧效应,在go干扰下却未被发现。研究结果证明,提取干扰对内隐记忆的影响主要由干扰任务与内隐记忆任务对认知资源的竞争导致。     

Dynamic states in working memory modulate guidance of visual attention: Evidence from an n-back paradigm

Items held in working memory (WM) can automatically bias attention when they reappear in visual displays. Recent evidence, however, suggests that WM biases of attention may be reduced under certain conditions, for example with increasing memory load. We employed a dual task paradigm to investigate how WM biases are affected by dynamic updating of memory contents. 1-back and 2-back versions of a memory task with colour stimuli were interrupted at intervals by an unrelated visual search task. Reappearance in the search display of the item that was currently active in WM guided attention, while suppressed or inactive items did not. We conclude that the rapid updating of memory contents facilitates the shifting of memory representations into different activity states on a moment-to-moment basis. The finding is consistent with models that propose that only one item can be “active” in WM at any one time to guide attention.     

Conceptual implicit memory and environmental context

Changes in environmental context between encoding and retrieval often affect explicit memory but research on implicit memory is equivocal. One proposal is that conceptual but not perceptual priming is influenced by context manipulations. However, findings with conceptual priming may be compromised by explicit contamination. The present study examined the effects of environmental context on conceptual explicit (category-cued recall) and implicit memory (category production). Explicit recall was reduced by context change. The implicit test results depended on test awareness (assessed with a post-test questionnaire). Among test-unaware participants, priming was equivalent for same-context and different-context groups, whereas for the test-aware, the same-context group produced more priming. Thus, when explicit contamination is controlled, changes in environmental context do not impair conceptual priming. Context dependency appears to be a general difference between implicit and explicit memory rather than a difference between conceptual and perceptual implicit memory. Finally, measures of mood indicated no changes in affect across contexts, arguing against mood mediation for the context effects in explicit recall.     

The basolateral amygdala modulates specific sensory memory representations in the cerebral cortex

Stress hormones released by an experience can modulate memory strength via the basolateral amygdala, which in turn acts on sites of memory storage such as the cerebral cortex [McGaugh, J. L. (2004). The amygdala modulates the consolidation of memories of emotionally arousing experiences. Annual Review of Neuroscience, 27, 1–28]. Stimuli that acquire behavioral importance gain increased representation in the cortex. For example, learning shifts the tuning of neurons in the primary auditory cortex (A1) to the frequency of a conditioned stimulus (CS), and the greater the level of CS importance, the larger the area of representational gain [Weinberger, N. M. (2007). Associative representational plasticity in the auditory cortex: A synthesis of two disciplines. Learning & Memory, 14(1–2), 1–16]. The two lines of research suggest that BLA strengthening of memory might be accomplished in part by increasing the representation of an environmental stimulus. The present study investigated whether stimulation of the BLA can affect cortical memory representations. In male Sprague–Dawley rats studied under urethane general anesthesia, frequency receptive fields were obtained from A1 before and up to 75 min after the pairing of a tone with BLA stimulation (BLAstm: 100 trials, 400 ms, 100 Hz, 400 μA [±16.54]). Tone started before and continued after BLAstm. Group BLA/1.0 (n = 16) had a 1 s CS–BLAstm interval while Group BLA/1.6 (n = 5) has a 1.6 s interval. The BLA/1.0 group did develop specific tuning shifts toward and to the CS, which could change frequency tuning by as much as two octaves. Moreover, its shifts increased over time and were enduring, lasting 75 min. However, group BLA/1.6 did not develop tuning shifts, indicating that precise CS–BLAstm timing is important in the anesthetized animal. Further, training in the BLA/1.0 paradigm but stimulating outside of the BLA did not produce tuning shifts. These findings demonstrate that the BLA is capable of exerting highly specific, enduring, learning-related modifications of stimulus representation in the cerebral cortex. These findings suggest that the ability of the BLA to alter specific cortical representations may underlie, at least in part, the modulatory influence of BLA activity on strengthening long-term memory.     

Interactions between visual working memory representations

We investigated whether the representations of different objects are maintained independently in working memory or interact with each other. Observers were shown two sequentially presented orientations and required to reproduce each orientation after a delay. The sequential presentation minimized perceptual interactions so that we could isolate interactions between memory representations per se. We found that similar orientations were repelled from each other whereas dissimilar orientations were attracted to each other. In addition, when one of the items was given greater attentional priority by means of a cue, the representation of the high-priority item was not influenced very much by the orientation of the low-priority item, but the representation of the low-priority item was strongly influenced by the orientation of the high-priority item. This indicates that attention modulates the interactions between working memory representations. In addition, errors in the reported orientations of the two objects were positively correlated under some conditions, suggesting that representations of distinct objects may become grouped together in memory. Together, these results demonstrate that working-memory representations are not independent but instead interact with each other in a manner that depends on attentional priority.     

Applying social psychology to the study of environmental concern and environmental worldviews: contributions from the social representations approach

Recently some social psychological approaches have intensified their contributions to research in the environmental domain, helping it to focus more consistently on the shared aspects of all environment related experiences. The goal of this paper is that of joining these efforts, exploring the contributions of the social representations approach to research on environmental concern and environmental thought, as another area for applying social psychological knowledge. The paper first sketches how the environmental concern of the publics emerged in the 70s as a problem for the social sciences and proceeds to summarizing the main characteristics of this research, focusing on three problematic areas: (1) incipient theoretical integration among the frameworks dominating research; (2) insufficient reflection about the assumptions and measurement of the concepts employed; (3) a need for new research questions that push studies beyond the analysis of the socio‐demographical correlates of beliefs. Afterwards a presentation of social representations theory will be undertaken and the usefulness of the approach to deal with some aspects of the problematic areas identified will be explored, with examples from recent research, and highlighting the importance of focusing on contradiction, polyphasia, and the articulation of the local and the global. Copyright © 2006 John Wiley & Sons, Ltd.     

The proposed interaction between working memory and inhibition

Two experiments investigated the determinants of performance on a go/no-go task by studying the interplay of two executive function components, working memory (WM) and inhibition. Systematically varied task demands on WM and inhibition were used in the analysis of performance together with individual capacity measures of both functions, thereby investigating an interactive view of WM and inhibition. Further analyses were conducted with individual differences in general fluid intelligence (gF), in an attempt to study the role of higher order cognition in handling task demands. The results are new in presenting empirical evidence for interactive effects of the task demand variables in concert with individual WM capacity as well as with gF, suggesting that executive processes common to WM and gF are involved in inhibitory performance, whereas gF appears to reflect a broader function in controlling behaviour in relation to task goals, whether it involves active responding or not.     

The construction of large number representations in adults

What is the nature of our mental representation of quantity? We find that human adults show no performance cost of comparing numerosities across vs. within visual and auditory stimulus sets, or across vs. within simultaneous and sequential sets. In addition, reaction time and performance in such tasks are determined by the ratio of the numerosities to be compared; absolute set size has no effect. These findings suggest that modality-specific stimulus properties undergo a non-iterative transformation into representations of quantity that are independent of the modality or format of the stimulus.     

Multisensory spatial representations in eye-centered coordinates for reaching

Humans can reach for objects with their hands whether the objects are seen, heard or touched. Thus, the position of objects is recoded in a joint-centered frame of reference regardless of the sensory modality involved. Our study indicates that this frame of reference is not the only one shared across sensory modalities. The location of reaching targets is also encoded in eye-centered coordinates, whether the targets are visual, auditory, proprioceptive or imaginary. Furthermore, the remembered eye-centered location is updated after each eye and head movement. This is quite surprising since, in principle, a reaching motor command can be computed from any non-visual modality without ever recovering the eye-centered location of the stimulus. This finding may reflect the predominant role of vision in human spatial perception.     

Attachment representations in mothers of preterm infants

The aim of the study was to assess attachment representations in mothers of preterm infants using the Working Model of Child Interview (WMCI) at the 12 months of the infant's corrected age. In addition, the relation between WMCI representation categories and the Edinburgh Postnatal Depression Scale score at 6 months of the infant's corrected age was studied. There were 38 mothers of preterm infants (<1500 g or <32 gestational weeks) and 45 mothers of full-term infants. The results showed no differences between the study groups in the distribution of the three main representation categories (balanced, disengaged and distorted). However, there were qualitative differences in representations between the groups. Furthermore, maternal depression symptoms were associated with distorted representation category. We suggest that despite the qualitative differences in the mothers’ representations, mothers of preterm infants are as likely to form balanced attachments with their infants as mothers of full-term infants.     

Mental representations of social status

How do people think about social status? We investigated the nature of social status and number representations using a semantic distance latency test. In Study 1, 21 college students compared words connoting different social status as well as numbers, which served as a control task. Participants were faster at comparing occupations and numbers that were semantically farther apart relative to those more closely related. In Study 2, we examined the semantic distance effect for a social status category, for which participants have as much knowledge of, as with numbers. We asked 15 US Navy Midshipmen to compare the social status associated with different ranks in the Navy as well as compare number magnitudes. Participants were fastest when comparing ranks far in status relative to ranks close in status. These findings reveal that humans have mental representations of social status that share properties with that of number.     

Reuse and body-formatted representations in simulation theory

I review the shifting definitions of simulation as found in recent versions of the simulation theory (ST) of social cognition. I focus on two concepts that have become central to recent ST in the work of a number of simulation theorists: the notion of reuse and the notion of B-formatted representations. I point out specific limitations or problems involved in these concepts. Although the reuse hypothesis provides an interesting evolutionary account of how neural mechanisms may adapt to new tasks, it doesn’t offer an explanation of how these mechanisms work. In contrast to the genuinely embodied account that simulation theorists seek, an explanation of social cognition in terms of B-formatted representations not only remains disembodied, but also ignores social interaction and remains solipsistic. I conclude by briefly outlining a non-simulationist enactivist account that can incorporate the reuse hypothesis.