The facilitative effect of positive stimuli on 3-year-olds’ flexible rule use

This study examined the effect of emotional stimuli on 3- to 4-year old children's flexible rule use, as measured by the Dimensional Change Card Sort (DCCS). In Experiment 1, children in two countries (Canada and China) were given 2 versions of the DCCS. The Standard version required children to sort red and blue boats and rabbits first by shape and then by color (or vice versa); the Emotional Faces version required children to sort happy and sad male and female faces first by emotion and then by gender (or vice versa). Children performed significantly better on the Emotional Faces version, and performance on the 2 versions was related. Order in which dimensions were presented had no effect. Experiment 2 examined which aspects of the emotional faces were responsible for the facilitation of children's performance. Performance on the Standard version was compared to performance on three contextual faces versions, in which children were shown happy, sad, or neutral faces and required to sort them by age (child versus adult) and then by gender (or vice versa). Facilitation was only seen in the context of happy faces. Results are consistent with the suggestion that positive stimuli promote cognitive flexibility, perhaps by increasing dopamine levels in prefrontal cortex.     

Bootstrapping the lexicon: a computational model of infant speech segmentation

Prelinguistic infants must find a way to isolate meaningful chunks from the continuous streams of speech that they hear. BootLex, a new model which uses distributional cues to build a lexicon, demonstrates how much can be accomplished using this single source of information. This conceptually simple probabilistic algorithm achieves significant segmentation results on various kinds of language corpora - English, Japanese, and Spanish; child- and adult-directed speech, and written texts; and several variations in coding structure - and reveals which statistical characteristics of the input have an influence on segmentation performance. BootLex is then compared, quantitatively and qualitatively, with three other groups of computational models of the same infant segmentation process, paying particular attention to functional characteristics of the models and their similarity to human cognition. Commonalities and contrasts among the models are discussed, as well as their implications both for theories of the cognitive problem of segmentation itself, and for the general enterprise of computational cognitive modeling.     

Children’s (in)ability to recover from garden paths in a verb-final language: Evidence for developing control in sentence processing

An eye-tracking study explored Korean-speaking adults’ and 4- and 5-year-olds’ ability to recover from misinterpretations of temporarily ambiguous phrases during spoken language comprehension. Eye movement and action data indicated that children, but not adults, had difficulty in recovering from these misinterpretations despite strong disambiguating evidence at the end of the sentence. These findings are notable for their striking similarities with findings from children parsing English; however, in those and other studies of English, children were found to be reluctant to use late-arriving syntactic evidence to override earlier verb-based cues to structure, whereas here Korean children were reluctant to use late-arriving verb-based cues to override earlier syntactic evidence. The findings implicate a general cross-linguistic pattern for parsing development in which late-developing cognitive control abilities mediate the recovery from so-called “garden path” sentences. Children’s limited cognitive control prevents them from inhibiting misinterpretations even when the disambiguating evidence comes from highly informative verb information.     

A computational model of fractionated conflict-control mechanisms in task-switching

A feature of human cognition is the ability to monitor and adjust one's own behavior under changing circumstances. A dynamic balance between controlled and rapid responding is needed to adapt to a fluctuating environment. We suggest that cognitive control may include, among other things, two distinct processes. Incongruent stimuli may drive top-down facilitation of task-relevant responses to bias performance toward exploitation vs. exploration. Task or response switches may generally slow responses to bias toward accuracy vs. speed and exploration vs. exploitation. Behavioral results from a task switching study demonstrate these two distinct processes as revealed by higher-order sequential effects. A computational model implements the two conflict-control mechanisms, which allow it to capture many complex and novel sequential effects. Lesion studies with the model demonstrate that the model is unable to capture these effects without the conflict-control loops and show how each monitoring component modulates cognitive control. The results suggest numerous testable predictions regarding the neural substrates of cognitive control.     

On the time course of exogenous cueing effects in bilinguals: Higher proficiency in a second language is associated with more rapid endogenous disengagement

Previous investigations have demonstrated a bilingual advantage on various aspects of executive control. It remains unclear how the language proficiency of bilinguals might relate to the mechanisms involved in attentional disengagement. In the present investigation, we tested the hypothesis that high bilingual proficiency would lead to a more rapid endogenous disengagement of attention from task-irrelevant peripheral cues. We predicted that more rapid attentional disengagement would result in an earlier appearance of inhibition of return (IOR). In this study Hindi–English bilinguals who differed in their L2 (English) proficiency participated in a target detection task. Visual targets were preceded by uninformative peripheral cues at various stimulus onset asynchronies (SOAs) allowing for us to visualize the time course of cue-related facilitation and inhibition. High-proficient Hindi–English bilinguals showed an earlier appearance of IOR than did low-proficient bilinguals, suggesting increased efficiency in disengagement of attention from task-irrelevant inputs. Furthermore, consistent with the “global” advantage that characterizes bilinguals in many tasks, the high-proficient group outperformed low-proficient bilinguals in overall reaction time.     

MOST intelligent people are accurate and SOME fast people are intelligent.: Intelligence,working memory,and semantic processing of quantifiers from a computational perspective

The paper explores the relationship between intelligence and the semantic processing of natural language quantifiers. The first study revealed that intelligence is positively associated with the subjects' performance when solving a picture verification task with one of the four types of sentences: Aristotelian (e.g. ‘All cars are red’), parity (e.g. ‘An even number of cars are red’), numerical (e.g. ‘More than five cars are red’), and proportional (‘More than half of the cars are red’). The strongest relationship was observed between the cognitive ability and the accuracy of proportional sentences, in accordance with the computational theory which predicts the highest engagement of working memory (WM) within the group of proportional quantifiers. Moreover, individuals with higher intelligence reacted faster, but this was observed only in case of quantifiers with low complexity. Exploring further, in the second study we found that WM and intelligence were both significant predictors of subjects' score on proportional sentences. In the third study, we examined the relationships between quantifiers, intelligence, short-term memory (STM), and executive control function. STM was correlated with all types of quantifiers that need counting and keeping track of elements (parity, numerical, and proportional). Only proportional quantifiers were associated with cognitive control. The obtained results are discussed within the computational paradigm of language processing.     

Executive control is shared between sentence processing and digit maintenance: Evidence from a strictly timed dual-task paradigm

We investigated whether the comprehension of syntactically difficult sentences taxes the executive control component of working memory more than the comprehension of their easier counterparts. To that end, we tested the effect of sharing executive control between sentence comprehension and the maintenance of a digit load in two dual-task experiments with strictly controlled timing (Barrouillet, Bernardin, & Camos, 2004). Recall was worse after participants had processed one (Experiment 2) or two (Experiment 1) difficult sentences than after they had processed one or two easy sentences, respectively. This finding suggests that sentence processing and the maintenance of a digit load share executive control. Processing syntactically difficult sentences seems to occupy executive control for a longer time than processing their easy counterparts, thereby blocking refreshments of the memory traces of the digits so that these traces decay more and recall is worse. There was no effect of the size of the digit load on sentence-processing performance (Experiment 2), suggesting that sentence processing completely occupied executive control until processing was complete.     

Too much control can hurt: A threaded cognition model of the attentional blink

Explanations for the attentional blink (AB; a deficit in identifying the second of two targets when presented 200-500 ms after the first) have recently shifted from limitations in memory consolidation to disruptions in cognitive control. With a new model based on the threaded cognition theory of multi-tasking we propose a different explanation: the AB is produced by an overexertion of control. This overexertion is produced by a production rule that blocks target detection during memory consolidation. In addition to fitting many known effects in the literature, the model predicts that adding certain secondary tasks will decrease the AB. In Experiment 1, a secondary task is added to the AB task in which participants have to respond to a moving dot. As predicted, AB decreases. Experiment 2 expands this result by controlling for learning, and adds a second variation, rotating the first target. For this variation the model predicts an increase in AB, which is indeed what we found.     

A putative role for neurogenesis in neurocomputational terms: Inferences from a hippocampal model

New neurons are generated daily in the hippocampus during adult life. They are integrated into the existing neuronal circuits according to several factors such as age, physical exercise and hormonal status. At present, the role of these new neurons is debated. Computational simulations of hippocampal function allow the effects of neurogenesis to be explored, at least from a computational perspective. The present work implements a model of neurogenesis in the hippocampus with artificial neural networks, based on a standard theoretical model of biologically plausible hippocampal circuits. The performance of the model in retrieval of a variable number of patterns or memories was evaluated (episodic memory evaluation). The model increased, in a phase subsequent to initial learning, the number of granular cells by 30% relative to their initial number. In contrast to a model without neurogenesis, the retrieval of recent memories was very significantly improved, although remotes memories were only slightly affected by neurogenesis. This increase in the quality of retrieval of new memories represents a clear advantage that we attribute to the neurogenesis process. This advantage becomes more significant for higher storage loads. The model presented here suggests an important functional role of neurogenesis on learning and memory.     

Comprehension of simple quantifiers: empirical evaluation of a computational model

We examine the verification of simple quantifiers in natural language from a computational model perspective. We refer to previous neuropsychological investigations of the same problem and suggest extending their experimental setting. Moreover, we give some direct empirical evidence linking computational complexity predictions with cognitive reality. In the empirical study we compare time needed for understanding different types of quantifiers. We show that the computational distinction between quantifiers recognized by finite-automata and push-down automata is psychologically relevant. Our research improves upon, the hypotheses and explanatory power of recent neuroimaging studies as well as provides evidence for the claim that human linguistic abilities are constrained by computational complexity.     

Open and closed cortico-subcortical loops: A neuro-computational account of access to consciousness in the distractor-induced blindness paradigm

How the brain decides which information to process ‘consciously’ has been debated over for decades without a simple explanation at hand. While most experiments manipulate the perceptual energy of presented stimuli, the distractor-induced blindness task is a prototypical paradigm to investigate gating of information into consciousness without or with only minor visual manipulation. In this paradigm, subjects are asked to report intervals of coherent dot motion in a rapid serial visual presentation (RSVP) stream, whenever these are preceded by a particular color stimulus in a different RSVP stream. If distractors (i.e., intervals of coherent dot motion prior to the color stimulus) are shown, subjects’ abilities to perceive and report intervals of target dot motion decrease, particularly with short delays between intervals of target color and target motion.We propose a biologically plausible neuro-computational model of how the brain controls access to consciousness to explain how distractor-induced blindness originates from information processing in the cortex and basal ganglia. The model suggests that conscious perception requires reverberation of activity in cortico-subcortical loops and that basal-ganglia pathways can either allow or inhibit this reverberation. In the distractor-induced blindness paradigm, inadequate distractor-induced response tendencies are suppressed by the inhibitory ‘hyperdirect’ pathway of the basal ganglia. If a target follows such a distractor closely, temporal aftereffects of distractor suppression prevent target identification. The model reproduces experimental data on how delays between target color and target motion affect the probability of target detection.     

A Computational Model for the Item‐Based Induction of Construction Networks

According to usage‐based approaches to language acquisition, linguistic knowledge is represented in the form of constructions—form‐meaning pairings—at multiple levels of abstraction and complexity. The emergence of syntactic knowledge is assumed to be a result of the gradual abstraction of lexically specific and item‐based linguistic knowledge. In this article, we explore how the gradual emergence of a network consisting of constructions at varying degrees of complexity can be modeled computationally. Linguistic knowledge is learned by observing natural language utterances in an ambiguous context. To determine meanings of constructions starting from ambiguous contexts, we rely on the principle of cross‐situational learning. While this mechanism has been implemented in several computational models, these models typically focus on learning mappings between words and referents. In contrast, in our model, we show how cross‐situational learning can be applied consistently to learn correspondences between form and meaning beyond such simple correspondences.     

The effect of repetitive saccade execution on the attention network test: Enhancing executive function with a flick of the eyes

The simple act of repeatedly looking left and right can enhance subsequent cognition, including divergent thinking, detection of matching letters from visual arrays, and memory retrieval. One hypothesis is that saccade execution enhances subsequent cognition by altering attentional control. To test this hypothesis, we compared performance following repetitive bilateral saccades or central fixation on the revised attention network test, which measures the operation of three distinct attentional networks: alerting, orienting, and executive function. The primary finding was that saccade execution increased the subsequent operation of the executive function network, which encompasses attentional control. Specifically, saccade execution decreased response time to target stimuli in the presence of response-incongruent flankers. A secondary finding was that saccade execution decreased response time to targets when an invalid location was cued prior to target onset. These findings suggest that saccades are an effective means of improving attentional control. Of greater theoretical importance, the study establishes attentional enhancement as a potential mechanism by which saccades enhance other aspects of cognition. Although some saccade execution effects have been found to depend on consistency of handedness (i.e., the consistency with which an individual uses one hand over the other), saccade-induced enhancement of attentional control occurred independently of handedness consistency.     

Using finite mixture of GLMs to explore variability in children's flexibility in a task-switching paradigm

The present study illustrates the usefulness of finite mixture of generalized linear models (GLMs) to examine variability in cognitive strategies during childhood. More precisely, it addresses this variability in set-shifting situations where task-goal updating is endogenously driven. In a task-switching paradigm 5–6-year-olds had to switch between color- and shape-matching rules as a function of a predetermined, predictable task sequence. A finite mixture of GLMs was fitted to explore individual differences in performance. The statistical model revealed five response profiles, defined by accuracy and response times. These response profiles likely correspond to different cognitive strategies with varying efficiency and differential relations to working memory capacity (assessed by backward digit span). These results illustrate the heuristic value of statistical modeling to reveal the behavioral and cognitive variability in the temporal dynamics of children's cognitive functioning.     

Optimal versus heuristic planning of object manipulations: A review and a computational model of the continuous end-state comfort effect

Human beings select actions that facilitate the execution of later actions. For example, humans tend to select grasps that ensure that forthcoming object manipulations end in a comfortable posture (“end-state comfort effect”). Basic experimental results and their explanation within the optimal control framework are reviewed. I conclude that the discrete grasp selection tasks, which are commonly used to study anticipatory planning, leave room for alternative explanations. Moreover, the results of seven experiments employing a continuous grasp selection task seem incompatible with the optimal control (of end-state comfort) account. I introduce the weighted integration of multiple biases (WIMB) model, which accounts for many aspects of the selection of human grasp orientations in continuous tasks. Additionally, it accounts for the precision effect and hysteresis effect. The model shows that the brain may rely on a simple heuristic and does not actually has to anticipate the end-state of a movement to select effective grasps for object manipulations.     

I blush, therefore I will be judged negatively: influence of false blush feedback on anticipated others’ judgments and facial coloration in high and low blushing-fearfuls

In the present study, we investigate whether people attribute costs to displaying a blush. Individuals with and without fear of blushing were invited to have a short conversation with two confederates. During the conversation, half of the individuals received the feedback that they were blushing intensely. The study tested whether the belief that one is blushing leads to the anticipation that one will be judged negatively. In addition, the set-up permitted the actual physiological blush response to be investigated. In line with the model that we propose for erythrophobia, participants in the feedback condition expected the confederates to judge them relatively negatively, independent of their fear of blushing. Furthermore, sustaining the idea that believing that one will blush can act as a self-fulfilling prophecy, high-fearfuls showed relatively intense facial coloration in both conditions, whereas low-fearfuls only showed enhanced blush responses following false blush feedback.     

Placing inspection time, reaction time, and perceptual speed in the broader context of cognitive ability: The VPR model in the Lothian Birth Cohort 1936

The idea that information processing speed is related to cognitive ability has a long history. Much evidence has been amassed in its support, with respect to both individual differences in general intelligence and developmental trajectories. Two so-called elementary cognitive tasks, reaction time and inspection time, have been used to compile this evidence, but most studies have used either one or the other. Relations between speed and fluid intelligence have tended to be stronger than those between speed and crystallized intelligence, but studies testing this have confounded verbal abilities with crystallized intelligence and spatial/perceptual abilities with fluid intelligence. Questions have also been raised regarding whether speed contributes directly to general intelligence or to more specific cognitive abilities to which general intelligence also contributes. We used 18 ability and speed measures in the Lothian Birth Cohort 1936, assessed at approximately age 70, to construct alternative versions of the Verbal-Perceptual-Image Rotation (Johnson & Bouchard, 2005a) model of cognitive ability to test different hypotheses regarding these issues. Though differences in the extents to which our models fit the data were relatively small, they suggested that reaction and inspection time tasks were comparable indicators of information processing speed with respect to general intelligence, that verbal and spatial abilities were similarly related to information processing speed, and that spatial, verbal, and perceptual speed abilities were more directly related to information processing speed than was general intelligence. We discuss the theoretical implications of these results.     

Posttraumatic stress disorder in the emergency room: exploration of a cognitive model

Ehlers and Clark (Behav. Res. Ther., 38 (2000) 319) recently proposed a cognitive model of posttraumatic stress disorder (PTSD). In this study, we examined two facets of this model, appraisal and peritraumatic dissociation, in the context of a hospital emergency room. Fifty-one emergency room personnel completed questionnaires measuring posttraumatic stress symptoms, interpretations of traumatic events experienced while working in the emergency room and subsequent intrusive recollections, and peritraumatic dissociation. Twelve percent of participants met formal diagnostic criteria for PTSD, and 20% met PTSD symptom criteria. As predicted, both negative appraisals of the trauma and of intrusive recollections were associated with increased PTSD severity. Although peritraumatic dissociation did not correlate with overall PTSD symptom severity, it was associated with the reexperiencing symptom cluster. Discussion focuses on the factors associated with PTSD in emergency room professionals and implications for intervention.     

Cost-effectiveness of Internet-based cognitive behavior therapy vs. cognitive behavioral group therapy for social anxiety disorder: results from a randomized controlled trial

Social anxiety disorder (SAD) is highly prevalent and associated with a substantial societal economic burden, primarily due to high costs of productivity loss. Cognitive behavior group therapy (CBGT) is an effective treatment for SAD and the most established in clinical practice. Internet-based cognitive behavior therapy (ICBT) has demonstrated efficacy in several trials in recent years. No study has however investigated the cost-effectiveness of ICBT compared to CBGT from a societal perspective, i.e. an analysis where both direct and indirect costs are included. The aim of the present study was to investigate the cost-effectiveness of ICBT compared to CBGT from a societal perspective using a prospective design. We conducted a randomized controlled trial where participants with SAD were randomized to ICBT (n = 64) or CBGT (n = 62). Economic data were assessed at pre-treatment, immediately following treatment and six months after treatment. Results showed that the gross total costs were significantly reduced at six-month follow-up, compared to pre-treatment in both treatment conditions. As both treatments were equivalent in reducing social anxiety and gross total costs, ICBT was more cost-effective due to lower intervention costs. We conclude that ICBT can be more cost-effective than CBGT in the treatment of SAD and that both treatments reduce societal costs for SAD.