Models provide specificity: Testing a proposed mechanism of visual working memory capacity development

Numerous studies have established that visual working memory has a limited capacity that increases during childhood. However, debate continues over the source of capacity limits and its developmental increase. Simmering (2008) adapted a computational model of spatial cognitive development, the Dynamic Field Theory, to explain not only the source of capacity limitations but also the developmental mechanism. Capacity is limited by the balance between excitation and inhibition that maintains multiple neural representations simultaneously in the model. Development occurs according to the Spatial Precision Hypothesis, which proposes that excitatory and inhibitory connections strengthen throughout early childhood. These changes in connectivity result in increasing precision and stability of neural representations over development. Here we test this developmental mechanism by probing children's memory in a single-item change detection task. Results confirmed the model's predictions, providing further support for this account of visual working memory capacity development.     

The importance of feature distribution and correlation for simulating 3 to 4-month-old infants' visual categorization processes

Mareschal, French, and Quinn (2000) and Mareschal, Quinn, and French (2002) have proposed a connectionist model of visual categorization in 3- to 4-month-old infants that simulates and predicts previously unexplained behavioural effects such as the asymmetric categorization effect (French, Mareschal, Mermillod, & Quinn, 2004). In the current paper, we show that the model's ability to simulate the asymmetry depends on the correlational structure of the stimuli. These results are important given that adults (Anderson & Fincham, 1996) as well as infants (Younger & Cohen, 1986) are able to rely on correlation information to perform visual categorization. At a behavioural level, the current paper suggests that pure bottom-up processes, based on the correlational structure of the categories, could explain the disappearance of the asymmetry in older 10-month-old infants (Furrer & Younger, 2005). Moreover, our results also raise new challenges for visual categorization models that attempt to simulate the shift from asymmetric categorization in 3- to 4-month-old to symmetric categorization in 10-month-old infants (Shultz & Cohen, 2004; Westermann & Mareschal, 2004, 2012).     

Feature synchrony-asynchrony and rate of change in visual search

ABSTRACT

Attention is known to be sensitive to the temporal structure of scenes. We initially tested whether feature synchrony, an attribute with potential special status because of its association with objecthood, is something which draws attention. Search items were surrounded by colours which periodically changed either in synchrony or out-of synchrony with periodic changes in their shape. Search for a target was notably faster when the target location contained a unique synchronous feature change amongst asynchronous changes. However, the reverse situation produced no search advantage. A second experiment showed that this effect of unique synchrony was actually a consequence of the lower rate of perceived flicker in the synchronous compared to the asynchronous items, not the synchrony itself. In our displays it seems that attention is drawn towards a location which has a relatively low rate of change. Overall, the pattern of results suggested the attentional bias we find is for relative temporal stability. Results stand in contrast to other work which has found high and low flicker rates to both draw attention equally [Cass, J., Van der Burg, E., & Alais, D. (2011). Finding flicker: Critical differences in temporal frequency capture attention. Frontiers in Psychology, 2, 320]. Further work needs to determine the exact conditions under which this bias is and is not found when searching in complex dynamically-changing displays.     

Mother–infant mutual eye gaze supports emotion regulation in infancy during the Still-Face paradigm

This study was designed to examine the sequential relationship between mother–infant synchrony and infant affect using multilevel modeling during the Still Face paradigm. We also examined self-regulatory behaviors that infants use during the Still-Face paradigm to modulate their affect, particularly during stressors where their mothers are not available to help them co-regulate. There were 84 mother–infant dyads, of healthy full term 4 month old infants. Second-by-second coding of infant self-regulation and infant affect was done, in addition to mother–infant mutual eye gaze. Using multilevel modeling, we found that infant affect became more positive when mutual gaze had occurred the previous second, suggesting that the experience of synchronicity was associated with observable shifts in affect. We also found a positive association between self-regulatory behaviors and increases in positive affect only during the Still-Face episode (episode 2). Our study provides support for the role of mother–infant synchronicity in emotion regulation as well as support for the role of self-regulatory behaviors in emotion regulation that can have important implication for intervention.     

Intention,Emotion, and Action: A Neural Theory Based on Semantic Pointers

We propose a unified theory of intentions as neural processes that integrate representations of states of affairs, actions, and emotional evaluation. We show how this theory provides answers to philosophical questions about the concept of intention, psychological questions about human behavior, computational questions about the relations between belief and action, and neuroscientific questions about how the brain produces actions. Our theory of intention ties together biologically plausible mechanisms for belief, planning, and motor control. The computational feasibility of these mechanisms is shown by a model that simulates psychologically important cases of intention.     

The relevance of sleep and circadian misalignment for procrastination among shift workers

This daily diary study contributes to current research uncovering the role of sleep for employees’ effective self‐regulation at work. We focus on shift workers’ effective self‐regulation in terms of their general and day‐specific inclination to procrastinate, that is, their tendency to delay the initiation or completion of work activities. We hypothesized that transitory sleep characteristics (day‐specific sleep quality and sleep duration) and chronic sleep characteristics in terms of circadian misalignment are relevant for procrastination. Sixty‐six shift workers completed two daily questionnaires over the course of one work week, resulting in 332 days of analysis. Results of multilevel regression analyses showed that on days when shift workers slept better and longer—compared to days when they slept worse and shorter—they had more energy and willpower available after sleep and subsequently were less prone to procrastination. Moreover, the more work times (permanent shift) were misaligned with employees’ sleep–wake preferences (chronotype) the more pronounced was shift workers’ inclination to procrastinate at work. The present findings provide important implications for shift workers’ effective functioning at work.

Practitioner Points

• To promote shift workers’ effective functioning at work, when scheduling shift work, circadian principles should be taken into account, and work times should be aligned with workers’ chronotypes.
• Day‐specific sleep quality and duration co‐vary with procrastination at work. Thus, on days on which procrastination would be especially harmful, sleep of good quality and of sufficient duration should be obtained.

     

Multi-tasking deep convolutional network architecture design for extracting nonverbal communicative information from a face

Facial expressions convey not only emotions but also communicative information. Therefore, facial expressions should be analysed to understand communication. The objective of this study is to develop an automatic facial expression analysis system for extracting nonverbal communicative information. This study focuses on specific communicative information: emotions expressed through facial movements and the direction of the expressions. We propose a multi-tasking deep convolutional network (DCN) to classify facial expressions, detect the facial regions, and estimate face angles. We reformulate facial region detection and face angle estimation as regression problems and add task-specific output layers in the DCN’s architecture. Experimental results show that the proposed method performs all tasks accurately. In this study, we show the feasibility of the multi-tasking DCN for extracting nonverbal communicative information from a human face.     

The Fragility of Evolution: Part Two

This essay argues for a shift in evolutionary metaphor-away from natural selection and the elimination of the less fit, to a focus on the fragility of biological change. Three biological arenas, in which the organism and environment more obviously interpenetrate, will be examined. The vulnerable and exceptionally plastic neural system of organisms makes possible subtle capacities such as learning and memory. Behavior, as it often precedes morphological change, emerges as an evolutionary axis. Synergisms between organisms lead to novelty on a macroevolutionary scale-multicellularity, coloniality, sociality, and eusociality. Although fragile due to competitive tensions, novel cohesions have repeatedly emerged throughout evolution. Ecology involves the flow of energy between organisms and the biophysical realm, which life has increasingly shaped. Radical spatial heterogeneity and varying levels of temporal disturbances serve to enhance biodiversity, and restrict the dominance of any single species. The atypical event of evolution can occur relatively suddenly and on varied scales. Paradoxically, evolution can be prompted by novel stresses and spaces protected from harsh competitive stress. As life moves to a greater total complexity, fragility increases. In conclusion, this essay discusses the protection of "less fit" human populations.     

Using Reinforcement Learning to Examine Dynamic Attention Allocation During Reading

A fundamental question in reading research concerns whether attention is allocated strictly serially, supporting lexical processing of one word at a time, or in parallel, supporting concurrent lexical processing of two or more words (Reichle, Liversedge, Pollatsek, & Rayner, 2009). The origins of this debate are reviewed. We then report three simulations to address this question using artificial reading agents (Liu & Reichle, 2010; Reichle & Laurent, 2006) that learn to dynamically allocate attention to 1–4 words to “read” as efficiently as possible. These simulation results indicate that the agents strongly preferred serial word processing, although they occasionally attended to more than one word concurrently. The reason for this preference is discussed, along with implications for the debate about how humans allocate attention during reading.     

Sex differences in neural efficiency: Are they due to the stereotype threat effect?

The neural efficiency hypothesis postulates a more efficient use of brain resources in more intelligent people as compared to less intelligent ones. However, this relationship was found to be moderated by sex and task content. While the phenomenon of neural efficiency was previously supported for men when performing visuo-spatial tasks it occurred for women only when performing verbal tasks. One possible explanation for this finding could be provided by the well-studied phenomenon called stereotype threat. Stereotype threat arises when a negative stereotype of one’s own group is made salient and can result in behavior that confirms the stereotype. Overall, 32 boys and 31 girls of varying intellectual ability were tested with a mental rotation task, either under a stereotype exposure or a no-stereotype exposure condition while measuring their EEG. The behavioral results show that an activated negative stereotype not necessarily hampers the performance of girls. Physiologically, a confirmation of the neural efficiency phenomenon was only obtained for boys working under a no-stereotype exposure condition. This result pattern replicates previous findings without threat and thus suggests that sex differences in neural efficiency during visuo-spatial tasks may not be due to the stereotype threat effect.