A mechanism for the formation of hippocampal neuronal firing patterns that represent what happens where

The association of specific events with the context in which they occur is a fundamental feature of episodic memory. However, the underlying network mechanisms generating what-where associations are poorly understood. Recently we reported that some hippocampal principal neurons develop representations of specific events occurring in particular locations (item-position cells). Here, we investigate the emergence of item-position selectivity as rats learn new associations for reward and find that before the animal's performance rises above chance in the task, neurons that will later become item-position cells have a strong selective bias toward one of two behavioral responses, which the animal will subsequently make to that stimulus. This response bias results in an asymmetry of neural activity on correct and error trials that could drive the emergence of particular item specificities based on a simple reward-driven synaptic plasticity mechanism.     

Reliability and validity of a bilingual measure of religiosity in English and Vietnamese: preliminary results from a pilot study

This study reports preliminary psychometric findings for a seven-item religiosity scale in a community-based sample of Vietnamese Americans ages 18 to 83 years (N = 119; 58% women, 42% men). A bilingual survey was distributed to Vietnamese who were evacuated during Hurricane Katrina and had returned after the disaster. Internal consistency, factorial structure validity, and criterion validity were evaluated on the scale items. The bilingual scale had good internal consistency. While exploratory and confirmatory factor analysis results provided support for a two-factor structure which captured Religious Involvement and Religious Coping, a one-factor model had slightly better fit. Individuals who scored high on the religiosity scale reported a significantly lower score on their stressful experiences during the hurricane, providing evidence of criterion validity.     

On the flexibility of letter position coding during lexical processing: the case of Thai

In Indo-European languages, letter position coding is particularly noisy in middle positions (e.g., judge and jugde look very similar), but not in the initial letter position (e.g., judge vs. ujdge). Here we focus on a language (Thai) which, potentially, may be more flexible with respect to letter position coding than Indo-European languages: (i) Thai is an alphabetic language which is written without spaces between words (i.e., there is a degree of ambiguity in relation to which word a given letter belongs to) and (ii) some of the vowels are misaligned (e.g., [see text] ε:bn/ is pronounced as /bε:n/), whereas others are not (e.g., [see text]/a:p/ is pronounced as /a:p/). We conducted a masked priming lexical decision experiment with 3-4 letter Thai words (with vs. without an initial misaligned vowel) in which the prime was: (i) identical to the target, (ii) a nonword generated by transposing the two initial letters of the target, or (iii) a replacement-letter control nonword. Results showed a significant masked transposed-letter priming effect in the initial letter positions, which was similar in size for words with and without an initial misaligned vowel. These findings reflect that: (i) letter position coding in Thai is very flexible and (ii) the nature of the obtained priming effects is orthographic rather than phonological.     

Further evidence for temporal decay in working memory: reply to Lewandowsky and Oberauer (2009)

The sources of forgetting in working memory (WM) are a matter of intense debate: Is there a time-related decay of memory traces, or is forgetting uniquely due to representation-based interference? In a previous study, we claimed to have provided evidence supporting the temporal decay hypothesis (S. Portrat, P. Barrouillet, & V. Camos, 2008). However, reanalyzing our data, S. Lewandowsky and K. Oberauer (2009) demonstrated that they do not provide compelling evidence for temporal decay and suggested a class of alternative models favoring a representation-based interference account. In this article, we develop from the most recent proposals made by Lewandowsky and Oberauer 2 of the most plausible extensions of these alternative models. We show that neither of these extensions can account for recent findings related to between-domain WM performance and that both lead to predictions that are contradicted by new empirical evidence. Finally, we show that recent studies that have been claimed to rule out the temporal decay hypothesis do not resist close scrutiny. We conclude that the time-based resource-sharing model remains the most parsimonious way to account for forgetting and restoration of memory traces in WM.     

Genetic architecture of context processing in late middle age: more than one underlying mechanism

Studies comparing young and older adults suggest a deficit in processing context information as a key mechanism underlying cognitive aging. However, the genetic architecture of context processing has not been examined. Consistent with previous results, we found evidence of functionally dissociable components of context processing accuracy in 1127 late middle-aged twins ages 51-60. One component emphasizes use of context cues to prepare responses (proactive cognitive control), and the other emphasizes adjustment of responses after probes are presented (reactive control). Approximately one-quarter of the variance in each component was accounted for by genes. Multivariate twin analysis indicated that genetic factors underlying two important components of context processing were independent of one another, thus implicating more than one underlying mechanism. Slower reaction time (RT) on noncontext processing trials was positively correlated with errors on the strongly proactive control component on which young adults outperform older adults, but RT was negatively correlated with errors on the strongly reactive control component on which older adults perform better. Although this RT measure was uncorrelated with chronological age in our age-homogeneous sample, slower RT was associated with performance patterns that were more like older adults. However, this did not generalize to other processing speed measures. Genetic correlations, which reflect shared genetic variance, paralleled the phenotypic correlations. There was also a positive genetic correlation between general cognitive ability and accuracy on the proactive control component, but there were still mostly distinct genetic influences underlying these measures. In contrast, the reactive control component was unrelated to general cognitive ability.     

Natural-scene perception requires attention

Is visual attention required for visual consciousness? In the past decade, many researchers have claimed that awareness can arise in the absence of attention. This claim is largely based on the notion that natural scene (or "gist") perception occurs without attention. This article presents evidence against this idea. We show that when observers perform a variety of demanding, sustained-attention tasks, inattentional blindness occurs for natural scenes. In addition, scene perception is impaired under dual-task conditions, but only when the primary task is sufficiently demanding. This finding suggests that previous studies that have been interpreted as demonstrating scene perception without attention failed to fully engage attention and that natural-scene perception does indeed require attention. Thus, natural-scene perception is not a preattentive process and cannot be used to support the idea of awareness without attention.     

In the beginning: role of autonomy support on the motivation, mental health and intentions of participants entering an exercise referral scheme

Self-determination theory (Deci & Ryan, 2000, Intrinsic motivation and self-determination in human behaviour. New York: Plenum Publishing) highlights the impact autonomy supportive environments can have on exercise motivation and positive health outcomes. Yet little is known about whether differential effects occur as a function of which significant other is providing this support. Further, no research has examined the relationship between motivation and the social environment with participants' mental health and intentions to be physically active before entering an exercise intervention. Study participants were 347 British adults who were about to start an exercise referral scheme. Regression analyses revealed that the effects of autonomy support on mental health and physical activity intentions differed as a function of who provided the support (offspring, partner or physician), with the offspring having the weakest effects. A structural model was supported, indicating that autonomy support and more autonomous regulations led to more positive mental health outcomes and stronger intentions to be physically active. Knowledge of the social environmental and personal motivation of those about to commence an exercise programme can provide important insights for professionals supporting such efforts.     

Mother-child play and maltreatment: a longitudinal analysis of emerging social behavior from infancy to toddlerhood

Mother-child play of maltreating and nonmaltreating families was analyzed when infants were 12 months old (Time 1), and 2 years old (Time 2), as a context to examine children's developing cognitive and social skills. At Time 1, infants from abusing families demonstrated less independent and more imitative behavior during play than did infants from neglecting and nonmaltreating families, suggesting a delay in emerging social behaviors. In this longitudinal follow-up, mother-child play was reassessed 1 year later (N = 78), with a focus on children's engagement in nonplay and pretend play and on children's abilities to initiate social exchanges and respond to parental requests. Play and social behavior were coded from semistructured and unstructured play paradigms at both time points. Maternal attention-directing behavior and limit setting also was assessed. At Time 2, children from abusing, neglecting, and nonmaltreating families did not differ in cognitive play complexity. However, children from abusing families engaged in less child-initiated play than did children from neglecting and nonmaltreating families, demonstrating less socially competent behavior. Longitudinal analyses revealed child initiated play at Time 2 was negatively associated with abuse and with maternal physical attention directing behavior at Time 1. Child negative reactivity at Time 2 was positively associated with Time 1 maternal physical behavior and child imitation and with Time 2 maternal controlling behavior. Implications for early intervention efforts are emphasized.     

Sleep hygiene behaviours: an application of the theory of planned behaviour and the investigation of perceived autonomy support, past behaviour and response inhibition

This study investigated the sleep hygiene behaviour of university students within the framework of the Theory of Planned Behaviour (TPB [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211.]), and examined the predictive validity of additional variables including perceived autonomy support, past behaviour and response inhibition. A total of 257 undergraduate students from an Australian university were administered two online questionnaires at two time points. At time 1, participants completed the TPB questionnaire and the Go/NoGo task as a measure of response inhibition. A week later at time 2, participants completed a questionnaire measuring the performance of sleep hygiene behaviours. Multiple and hierarchical regression analyses showed that the TPB model significantly predicted intention and behaviour. Although intention and perceived behavioural control were statistically significant in predicting behaviour, past behaviour and response inhibition accounted for more variance when added to the TPB model. Subjective norm was found to be the strongest predictor of intention implying the importance of normative influences in sleep hygiene behaviours. Response inhibition was the strongest predictor of behaviour, reinforcing the argument that the performance of health protective behaviours requires self-regulatory ability. Therefore, interventions should be targeted at enhancing self-regulatory capacity.