Neurocognitive development and externalizing problems: the role of inhibitory control deficits from 4 to 6 years

Executive processes have been posited as important regulators of externalizing problems (EP), but there has been little research on the relation between executive dysfunction and EP in early childhood. During the preschool period, maturation of the prefrontostriatal circuitry parallels increases in inhibitory control (IC). Poor IC development could result in elevated levels of aggressive, disruptive, and impulsive behavior. In this investigation, the development of the relation between IC and EP was examined in preschool and early elementary school children using the Day/Night and Tapping tasks. Children with more EP made more incorrect responses on both IC tasks, consistently across age and sex. The associations between EP and response latencies differed across children, however, with longer latencies on the Tapping task being most characteristic for boys with high levels of EP. This association was not apparent for girls. Two prominent aspects of early EP, aggressive and inattentive behavior, showed only weak unique associations with IC performance. These findings imply that diminished IC accompanies elevated EP as early as the preschool years, and that this decrement persists into the elementary school-age years for both girls and boys, and that accuracy and response latency may confer different information about the development of IC.     

Fishing for happiness: the effects of generating positive imagery on mood and behaviour

Experimental evidence using picture-word cues has shown that generating mental imagery has a causal impact on emotion, at least for images prompted by negative or benign stimuli. It remains unclear whether this finding extends to overtly positive stimuli and whether generating positive imagery can increase positive affect in people with dysphoria. Dysphoric participants were assigned to one of three conditions, and given instructions to generate mental images in response to picture-word cues which were either positive, negative or mixed (control) in valence. Results showed that the positive picture-word condition increased positive affect more than the control and negative conditions. Participants in the positive condition also demonstrated enhanced performance on a behavioural task compared to the two other conditions. Compared to participants in the negative condition, participants in the positive condition provided more positive responses on a homophone task administered after 24h to assess the durability of effects. These findings suggest that a positive picture-word task used to evoke mental imagery leads to improvements in positive mood, with transfer to later performance. Understanding the mechanisms underlying mood change in dysphoria may hold implications for both theory and treatment development.     

Influence of facial expression on memory for facial identity: effects of visual features or emotional meaning?

Research has shown that neutral faces are better recognized when they had been presented with happy rather than angry expressions at study, suggesting that emotional signals conveyed by facial expressions influenced the encoding of novel facial identities in memory. An alternative explanation, however, would be that the influence of facial expression resulted from differences in the visual features of the expressions employed. In this study, this possibility was tested by manipulating facial expression at study versus test. In line with earlier studies, we found that neutral faces were better recognized when they had been previously encountered with happy rather than angry expressions. On the other hand, when neutral faces were presented at study and participants were later asked to recognize happy or angry faces of the same individuals, no influence of facial expression was detected. As the two experimental conditions involved exactly the same amount of changes in the visual features of the stimuli between study and test, the results cannot be simply explained by differences in the visual properties of different facial expressions and may instead reside in their specific emotional meaning. The findings further suggest that the influence of facial expression is due to disruptive effects of angry expressions rather than facilitative effects of happy expressions. This study thus provides additional evidence that facial identity and facial expression are not processed completely independently.     

Learning implicitly to produce avoided behaviours

The literature on repetition processing reveals an intriguing paradox between the particular salience of repetitions, which makes them easy to learn, and a tendency to avoid them when generating sequences. The aim of this experiment was to study the extent to which children can learn to produce these avoided behaviours by means of an artificial grammar paradigm using generation tests with implicit or explicit instructions. The analysis of the control group's performance confirmed the presence of a spontaneous tendency to avoid generating repetitions. A comparison with chance revealed that the children learned to produce repetitions in the explicit test but not in the implicit test. However, a comparison with the control group showed that learning nonetheless occurred in the experimental group with the implicit test. The discussion focused on this antirepetition behavioural bias and how it interacted with the type of information processes elicited by the tests selected for assessing implicit learning effects.     

Role of action observation and action in sequence learning and coding

A complex sequence learning task was used to determine if the type of coding acquired through physical practice (PP), observation of the stimulus (Obs-S), or observation of stimulus and action (Obs-SA) differs between conditions and whether the type of observation influences subsequent learning of the task when physical practice was permitted. Participants in the Obs-S group were permitted to watch the sequentially illuminated stimuli on the screen. In the Obs-SA group participants could see both flexion-extension movements of the model's arm performing the sequence and the sequentially illuminated stimuli on the screen. Participants in the PP group actually performed the 16-element sequence with their dominant right arm. Delayed retention tests and two inter-manual transfer tests were completed following each of two acquisition sessions. First, the data indicated that learning the sequence structure, as revealed by response time per element, occurred similarly irrespective of the initial practice condition. Secondly, the movement sequence appeared to be coded in abstract visual-spatial coordinates resulting in effector-independent performance. Finally, observing the model's action and sequential stimuli allows participants to transfer the perceived aspects of the movement sequence into efficient coordination patterns when additional physical practice is permitted.     

Working memory for ballet moves and spatial locations in professional ballet dancers

The aim of the present study was to investigate working memory for ballet moves in expert dancers. Experiment 1 showed that a concurrent spatial task did not interfere with the recall of a sequence of ballet moves when these were encoded alone without being associated with spatial locations. Experiment 2 showed that a concurrent motor task selectively interfered with the recall of ballet moves while neither a concurrent motor task nor a spatial task affected recall of the specific locations where each ballet move had to be performed. Experiment 3 showed that spatial interference affected recall of sequences of locations when these were encoded alone. Finally, in Experiment 4, a similarity effect for patterned ballet movements was shown. Taken together results show that spatial interference does not affect short‐term memory for ballet moves thus suggesting that working memory might contain a system for motor configurations. Copyright © 2009 John Wiley & Sons, Ltd.     

Phenomenal characteristics of autobiographical memories for positive,negative, and neutral events

We investigated memory qualities for positive, negative, and neutral autobiographical events. Participants recalled two personal experiences of each type and then rated their memories on several characteristics (e.g. sensorial and contextual details). They also reported whether they ‘see’ the events in their memories from their own perspective (‘field’ memories) or whether they ‘see’ the self engaged in the event as an observer would (‘observer’ memories). Positive memories contained more sensorial (visual, smell, taste) and contextual (location, time) details than both negative and neutral events, whereas negative and neutral memories did not differ on most dimensions. Positive and negative events were more often recollected with a field perspective than neutral events. Finally, participants were classified in four groups according to the repressive coping style framework. Emotional memories of repressors were not less detailed than those of the other groups. Copyright © 2002 John Wiley & Sons, Ltd.     

The neural correlates of implicit and explicit sequence learning: Interacting networks revealed by the process dissociation procedure

In two H2(15)O PET scan experiments, we investigated the cerebral correlates of explicit and implicit knowledge in a serial reaction time (SRT) task. To do so, we used a novel application of the Process Dissociation Procedure, a behavioral paradigm that makes it possible to separately assess conscious and unconscious contributions to performance during a subsequent sequence generation task. To manipulate the extent to which the repeating sequential pattern was learned explicitly, we varied the pace of the choice reaction time task-a variable that is known to have differential effects on the extent to which sensitivity to sequence structure involves implicit or explicit knowledge. Results showed that activity in the striatum subtends the implicit component of performance during recollection of a learned sequence, whereas the anterior cingulate/mesial prefrontal cortex (ACC/MPFC) supports the explicit component. Most importantly, we found that the ACC/MPFC exerts control on the activity of the striatum during retrieval of the sequence after explicit learning, whereas the activity of these regions is uncoupled when learning had been essentially implicit. These data suggest that implicit learning processes can be successfully controlled by conscious knowledge when learning is essentially explicit. They also supply further evidence for a partial dissociation between the neural substrates supporting conscious and nonconscious components of performance during recollection of a learned sequence.     

Influence of emotion on memory for temporal information

Contextual information, such as color and spatial location, has been found to be better remembered for emotional than for neutral items. The current study examined whether the influence of emotion extends to memory for another fundamental feature of episodic memory: temporal information. Results from a list-discrimination paradigm showed that (a) item memory was enhanced for both negative and positive pictures compared with neutral ones and was better for negative than for positive pictures and (b) temporal information was better remembered for negative than for positive and neutral pictures, whereas positive and neutral pictures did not differ from each other. These findings are discussed in relation to the processes involved in memory for temporal information.