The representation of delayed intentions: a prospective subject-performed task?

To-be-enacted material is more accessible in tests of recognition and lexical decision than material not intended for action (T. Goschke J. Kuhl, 1993; R. L. Marsh, J. L. Hicks, & M. L. Bink, 1998). This finding has been attributed to the superior status of intention-related information. The current article explores an alternative (action-superiority) account that draws parallels between the intended enactment effect (IEE) and the subject-performed task effect. Using 2 paradigms, the authors observed faster recognition latencies for both enacted and to-be-enacted material. It is crucial to note that there was no evidence of an IEE for items that had already been executed during encoding. The IEE was also eliminated when motor processing was prevented after verbal encoding. These findings suggest an overlap between overt and intended enactment and indicate that motor information may be activated for verbal material in preparation for subsequent execution.

Implicit memory and consumer choice: the mediating role of brand familiarity

Two experiments investigated the influence of implicit memory on consumer choice for brands with varying levels of familiarity. Priming was measured using a consideration-choice task, developed by Coates, Butler and Berry (2004). Experiment 1 employed a coupon-rating task at encoding that required participants to meaningfully process individual brand names, to assess whether priming could affect participants' final (preferred) choices for familiar brands. Experiment 2 used this same method to assess the impact of implicit memory on consideration and choice for unknown and leader brands, presented in conjunction with familiar competitors. Significant priming was obtained in both experiments, and was shown to directly influence final choice in the case of familiar and highly familiar leader brands. Moreover, it was shown that a single prior exposure could lead participants to consider buying an unknown, and indeed fictitious, brand. Copyright (c) 2006 John Wiley & Sons, Ltd.

Implicit memory: a prime example for brand consideration and choice

Three experiments investigated the influence of implicit memory for familiar brand names on consumer choice. Priming was measured using modified preference judgment tasks that comprised both brand consideration and choice components. Experiment 1 used a 'complex choice task' where consideration and choice stages were characterized as acting in sequence. Experiment 2 explored a different formulation whereby consideration and choice were assumed to act in parallel, Both experiments demonstrated that priming had an influence on brand consideration but not on final or preferred choice. Finally, Experiment 3 replicated and extended these findings under more realistic conditions where participants actually received some of the products that they selected. Overall, the experiments suggested that for many decisions involving the consideration of familiar brands prior to choice, previous exposure to brand names can increase the likelihood that they will enter the consumers' consideration set. However, the advantage does not appear to extend to choice itself. Copyright (C) 2004 John Wiley Sons, Ltd.

Evaluating a realistic agent in an advice-giving task

The aim of this study was to empirically evaluate an embodied conversational agent called GRETA in an effort to answer two main questions: (1) What are the benefits (and costs) of presenting information via an animated agent, with certain characteristics, in a 'persuasion' task, compared to other forms of display? (2) How important is it that emotional expressions are added in a way that is consistent with the content of the message, in animated agents? To address these questions, a positively framed healthy eating message was created which was variously presented via GRETA, a matched human actor, GRETA's voice only (no face) or as text only. Furthermore, versions of GRETA were created which displayed additional emotional facial expressions in a way that was either consistent or inconsistent with the content of the message. Overall, it was found that although GRETA received significantly higher ratings for helpfulness and likability, presenting the message via GRETA led to the poorest memory performance among users. Importantly, however, when GRETA's additional emotional expressions were consistent with the content of the verbal message, the negative effect on memory performance disappeared. Overall, the findings point to the importance of achieving consistency in animated agents. (c) 2005 Elsevier Ltd. All rights reserved.

Memory operations in rapid serial visual presentation

Short-term memory (STM) has often been considered to be a central resource in cognition. This study addresses its role in rapid serial visual presentation (RSVP) tasks tapping into temporal attention-the attentional blink (AB). Various STM operations are tested for their impact on performance and, in particular, on the AB. Memory tasks were found to exert considerable impact on general performance but the size of the AB was more or less immune to manipulations of STM load. Likewise, the AB was unaffected by manipulating the match between items held in STM and targets or temporally close distractors in the RSVP stream. The emerging picture is that STM resources, or their lack, play no role in the AB. Alternative accounts assuming serial consolidation, selection for action, and distractor-induced task-set interference are discussed.

Short-term memory and the attentional blink: capacity versus content

When people monitor the rapid serial visual presentation (RSVP) of stimuli for two targets (T1 and T2), they often miss T2 if it falls into a time window of about half a second after T1 onset, a phenomenon known as the attentional blink (AB). We found that overall performance in an RSVP task was impaired by a concurrent short-term memory (STM) task and, furthermore, that this effect increased when STM load was higher and when its content was more task relevant. Loading visually defined stimuli and adding articulatory suppression further impaired performance on the RSVP task, but the size of the AB over time (i.e., T1-T2 lag) remained unaffected by load or content. This suggested that at least part of the performance in an RSVP task reflects interference between competing codes within STM, as interference models have held, whereas the AB proper reflects capacity limitations in the transfer to STM, as consolidation models have claimed.

Understanding of auditory discourse in older adults: the effects of syntax and working memory

Background: As people age, language-processing ability changes. While several factors modify discourse comprehension ability in older adults, syntactic complexity of auditory discourse has received scant attention. This is despite the widely researched domain of syntactic processing of single sentences in older adults. Aims: The aims of this study were to investigate the ability of healthy older adults to understand stories that differed in syntactic complexity, and its relation to working memory. Methods & Procedures: A total of 51 healthy adults (divided into three age groups) took part. They listened to brief stories (syntactically simple and syntactically complex) and had to respond to false/true comprehension probes following each story. Working memory capacity (digit span, forward and backward) was also measured. Outcomes & Results: Differences were found in the ability of healthy older adults to understand simple and complex discourse. The complex discourse in particular was more sensitive in discerning age-related language patterns. Only the complex discourse task correlated moderately with age. There was no correlation between age and simple discourse. As far as working memory is concerned, moderate correlations were found between working memory and complex discourse. Education did not correlate with discourse, neither simple, nor complex. Conclusions: Older adults may be less efficient in forming syntactically complex representations and this may be influenced by limitations in working memory.

Speech perception and phonological short-term memory capacity in language impairment: preliminary evidence from adolescents with specific language impairment (SLI) and autism spectrum disorders (ASD)

Background: The cognitive bases of language impairment in specific language impairment (SLI) and autism spectrum disorders (ASD) were investigated in a novel non-word comparison task which manipulated phonological short-term memory (PSTM) and speech perception, both implicated in poor non-word repetition. Aims: This study aimed to investigate the contributions of PSTM and speech perception in non-word processing and whether individuals with SLI and ASD plus language impairment (ALI) show similar or different patterns of deficit in these cognitive processes. Method & Procedures: Three groups of adolescents (aged 14–17 years), 14 with SLI, 16 with ALI, and 17 age and non-verbal IQ matched typically developing (TD) controls, made speeded discriminations between non-word pairs. Stimuli varied in PSTM load (two- or four-syllables) and speech perception load (mismatches on a word-initial or word-medial segment). Outcomes & Results: Reaction times showed effects of both non-word length and mismatch position and these factors interacted: four-syllable and word-initial mismatch stimuli resulted in the slowest decisions. Individuals with language impairment showed the same pattern of performance as those with typical development in the reaction time data. A marginal interaction between group and item length was driven by the SLI and ALI groups being less accurate with long items than short ones, a difference not found in the TD group. Conclusions & Implications: Non-word discrimination suggests that there are similarities and differences between adolescents with SLI and ALI and their TD peers. Reaction times appear to be affected by increasing PSTM and speech perception loads in a similar way. However, there was some, albeit weaker, evidence that adolescents with SLI and ALI are less accurate than TD individuals, with both showing an effect of PSTM load. This may indicate, at some level, the processing substrate supporting both PSTM and speech perception is intact in adolescents with SLI and ALI, but also in both there may be impaired access to PSTM resources.

Autobiographical memory and the self in a case of transient epileptic amnesia

Transient epileptic amnesia (TEA) is characterized by deficits in autobiographical memory (AM). One of the functions of AM is to maintain the self, suggesting that the self may undergo changes as a result of memory loss in temporal lobe epilepsy. To examine this, we used a modification of a task used to assess the relationship between self and memory (the IAM task) in a single case, E.B. Despite complaints of AM loss, E.B. had no difficulty in producing a range of self-images (e.g., I am a husband) and collections of self-defining AMs in support of these statements. E.B. produced fewer episodic memories at times of self-formation, but this did not seem to impact on the maintenance of self. The results support recent work suggesting the self may be maintained in the absence of episodic memory. The application of tasks such as that used here will further elucidate AM impairment in temporal lobe epilepsy. (C) 2011 Elsevier Inc. All rights reserved.

Blueberry supplementation induces spatial memory improvements and region-specific regulation of hippocampal BDNF mRNA expression in young rats

Rationale: Flavonoid-rich foods have been shown to be able to reverse age-related cognitive deficits in memory and learning in both animals and humans. However, to date, there have been only a limited number of studies investigating the effects of flavonoid-rich foods on cognition in young/healthy animals. Objectives: The aim of this study was to investigate the effects of a blueberry-rich diet in young animals using a spatial working memory paradigm, the delayed non-match task, using an eight-arm radial maze. Furthermore, the mechanisms underlying such behavioural effects were investigated. Results: We show that a 7-week supplementation with a blueberry diet (2 % w/w) improves the spatial memory performance of young rats (2 months old). Blueberry-fed animals also exhibited a faster rate of learning compared to those on the control diet. These behavioural outputs were accompanied by the activation of extracellular signal-related kinase (ERK1/2), increases in total cAMP-response element binding protein (CREB) and elevated levels of pro- and mature brain-derived neurotrophic factor (BDNF) in the hippocampus. Changes in hippocampal CREB correlated well with memory performance. Further regional analysis of BDNF gene expression in the hippocampus revealed a specific increase in BDNF mRNA in the dentate gyrus and CA1 areas of hippocampi of blueberry-fed animals. Conclusions: The present study suggests that consumption of flavonoid-rich blueberries has a positive impact on spatial learning performance in young healthy animals, and these improvements are linked to the activation of ERK–CREB– BDNF pathway in the hippocampus.

Causal evidence for frontal involvement in memory target maintenance by posterior brain areas during distracter interference of visual working memory

Dorsolateral prefrontal cortex (DLPFC) is recruited during visual working memory (WM) when relevant information must be maintained in the presence of distracting information. The mechanism by which DLPFC might ensure successful maintenance of the contents of WM is, however, unclear; it might enhance neural maintenance of memory targets or suppress processing of distracters. To adjudicate between these possibilities, we applied time-locked transcranial magnetic stimulation (TMS) during functional MRI, an approach that permits causal assessment of a stimulated brain region's influence on connected brain regions, and evaluated how this influence may change under different task conditions. Participants performed a visual WM task requiring retention of visual stimuli (faces or houses) across a delay during which visual distracters could be present or absent. When distracters were present, they were always from the opposite stimulus category, so that targets and distracters were represented in distinct posterior cortical areas. We then measured whether DLPFC-TMS, administered in the delay at the time point when distracters could appear, would modulate posterior regions representing memory targets or distracters. We found that DLPFC-TMS influenced posterior areas only when distracters were present and, critically, that this influence consisted of increased activity in regions representing the current memory targets. DLPFC-TMS did not affect regions representing current distracters. These results provide a new line of causal evidence for a top-down DLPFC-based control mechanism that promotes successful maintenance of relevant information in WM in the presence of distraction.

Epoch-specific functional networks involved in working memory

Working memory (WM) is not a unitary construct. There are distinct processes involved in encoding information, maintaining it on-line, and using it to guide responses. The anatomical configurations of these processes are more accurately analyzed as functionally connected networks than collections of individual regions. In the current study we analyzed event-related functional magnetic resonance imaging (fMRI) data from a Sternberg Item Recognition Paradigm WM task using a multivariate analysis method that allowed the linking of functional networks to temporally-separated WM epochs. The length of the delay epochs was varied to optimize isolation of the hemodynamic response (HDR) for each task epoch. All extracted functional networks displayed statistically significant sensitivity to delay length. Novel information extracted from these networks that was not apparent in the univariate analysis of these data included involvement of the hippocampus in encoding/probe, and decreases in BOLD signal in the superior temporal gyrus (STG), along with default-mode regions, during encoding/delay. The bilateral hippocampal activity during encoding/delay fits with theoretical models of WM in which memoranda held across the short term are activated long-term memory representations. The BOLD signal decreases in the STG were unexpected, and may reflect repetition suppression effects invoked by internal repetition of letter stimuli. Thus, analysis methods focusing on how network dynamics relate to experimental conditions allowed extraction of novel information not apparent in univariate analyses, and are particularly recommended for WM experiments for which task epochs cannot be randomized.

The sample autocorrelation function and the detection of long-memory processes

The detection of long-range dependence in time series analysis is an important task to which this paper contributes by showing that whilst the theoretical definition of a long-memory (or long-range dependent) process is based on the autocorrelation function, it is not possible for long memory to be identified using the sum of the sample autocorrelations, as usually defined. The reason for this is that the sample sum is a predetermined constant for any stationary time series; a result that is independent of the sample size. Diagnostic or estimation procedures, such as those in the frequency domain, that embed this sum are equally open to this criticism. We develop this result in the context of long memory, extending it to the implications for the spectral density function and the variance of partial sums of a stationary stochastic process. The results are further extended to higher order sample autocorrelations and the bispectral density. The corresponding result is that the sum of the third order sample (auto) bicorrelations at lags h,k≥1, is also a predetermined constant, different from that in the second order case, for any stationary time series of arbitrary length.

Prefrontal inhibition of threat processing reduces working memory interference

Bottom-up processes can interrupt ongoing cognitive processing in order to adaptively respond to emotional stimuli of high potential significance, such as those that threaten wellbeing. However it is vital that this interference can be modulated in certain contexts to focus on current tasks. Deficits in the ability to maintain the appropriate balance between cognitive and emotional demands can severely impact on day-to-day activities. This fMRI study examined this interaction between threat processing and cognition; 18 adult participants performed a visuospatial working memory (WM) task with two load conditions, in the presence and absence of anxiety induction by threat of electric shock. Threat of shock interfered with performance in the low cognitive load condition; however interference was eradicated under high load, consistent with engagement of emotion regulation mechanisms. Under low load the amygdala showed significant activation to threat of shock that was modulated by high cognitive load. A directed top-down control contrast identified two regions associated with top-down control; ventrolateral PFC and dorsal ACC. Dynamic causal modeling provided further evidence that under high cognitive load, top-down inhibition is exerted on the amygdala and its outputs to prefrontal regions. Additionally, we hypothesized that individual differences in a separate, non-emotional top-down control task would predict the recruitment of dorsal ACC and ventrolateral PFC during top-down control of threat. Consistent with this, performance on a separate dichotic listening task predicted dorsal ACC and ventrolateral PFC activation during high WM load under threat of shock, though activation in these regions did not directly correlate with WM performance. Together, the findings suggest that under high cognitive load and threat, top-down control is exerted by dACC and vlPFC to inhibit threat processing, thus enabling WM performance without threat-related interference.

An investigation of working memory effects on oral grammatical accuracy and fluency in producing questions in English

This article addresses the question of how far working memory may affect second language (L2) learners' improvement in spoken language during a period of immersion. Research is presented testing the hypothesis that individual differences in working memory (WM) capacity are associated with individual variation in improvements in oral production of questions in English. Thirty-two Chinese adult speakers of English were tested, before and after a year's postgraduate study in the United Kingdom, to measure grammatical accuracy and fluency using a question elicitation task, and to measure WM using a battery of first language (L1) and L2 WM tests. Story recall in L1 (Mandarin) was significantly associated with individuals' improvement in oral grammatical measures (p < .05). However, there was no significant mean improvement across the cohort in grammatical accuracy, although there was for fluency. The findings suggest that WM may aid certain aspects of individuals' L2 oral proficiency during academic immersion through postgraduate study. They also indicate that academic immersion in itself can lead to improvements in oral proficiency, independent of WM capacity, but there is no general guarantee of significant grammatical change. Further research to clarify the opportunities for input and interaction available in academic immersion settings is called for.