Increasing convergence between imagined and executed movement across development: evidence for the emergence of movement representations

Motor imagery (MI) has become a principal focus of interest in studies on brain and behavior. However, changes in MI across development have received virtually no attention so far. In the present study, children (N = 112, 6 to 16 years old) performed a new, computerized Virtual Radial Fitts Task (VRFT) to determine their MI ability as well as the age‐related confluence between performance in executed and imagined movement conditions. Participants aimed at five targets, which were positioned along radial axes from a central target circle. The targets differed in width (2.5, 5, 10, 20 or 40 mm), resulting in an index of difficulty (ID) that varied from 6.9 to 2.9 bits. Performance was indexed by the linear relationship between ID and Movement Time (MT). The findings showed that executed task performance was slower than imagined performance. Moreover, conformance to Fitts’ Law during executed movement performance was obtained from a very young age. Most importantly, correlations between imagined and executed movements were low in the young participants but gradually increased across age. These age‐related changes in MI are hypothesized to reflect the children's emerging ability to represent internal models for prospective actions, consistent with the gradual unfolding of feedforward control processes.     

Toward the use of approach/avoidance tendencies as attitude measures: Individual- and group-level variability of the ingroup bias

Approach/avoidance paradigms could constitute an interesting alternative in measuring intergroup attitudes, notably if they overcome one criticism often addressed toward classic indirect tasks: Measuring attitudes beyond the influence of cultural knowledge. Using intergroup stimuli and a population likely to be exposed to a similar cultural knowledge, we observed two informative results regarding this issue: Approach/avoidance effects measured by the Visual Approach/Avoidance by the Self Task (VAAST) varied across participants (i.e., consistent with the variability of intergroup attitudes; Experiment 1) and both participants of dominant and non-dominant groups produced an ingroup bias (Experiment 2). A last experiment (Experiment 3) showed that compatibility scores in the VAAST predict trustworthiness ratings of the ingroup/outgroup. This experiment also investigated potential differences between the VAAST and the IAT. These results suggest that approach/avoidance tasks (notably the VAAST) could be relevant to assess personal attitudes when it comes to normatively sensitive topics.     

Delay discounting: Interactions between personality and cognitive ability

Delay discounting describes the extent to which the value of a reward decreases as the delay to obtaining that reward increases. Lower discounting rates predict better outcomes in social, academic, and health domains. The current study investigates how personality and cognitive ability interact to predict individual differences in delay discounting. Extraversion was found to predict higher discounting rates at the low end of the cognitive distribution, while emotional stability was found to predict lower discounting rates at the high end of the cognitive distribution. These findings support recent models of discounting behavior and suggest that personality and cognitive ability interact in shaping decision making.     

Modeling continuity and discontinuity in utterance length: a quantitative approach to changes, transitions and intra-individual variability in early grammatical development

The confluence of an anomaly such as a growth spurt or a temporary regression on the one hand and a temporary increase in intra-individual variability on the other hand, forms a strong indicator of a major transition in early language development. Data concern one-word (W1), two- and three-word (W2-3), and four-and-more-word (W4+) utterances from two French children during their second and third years. A dynamic growth model was fitted, based on a structure of supportive, conditional and competitive relationships. Using a statistical simulation method, we showed two striking peaks of variability in addition to a temporary regression or rapid growth in the proportions of W1, W2-3 and W4+ utterances. We argue that these phenomena show transitions corresponding to critical points in grammatical development, which could be indicative of the emergence of simple combinatorial and syntactic stages of language successively. Our results emphasize the relevance of time-serial data and of intra-individual variability in the study of developmental transitions in general.     

Two-to-three-year-old children's interactions with peers in child-care centres: Effects of spatial distance to caregivers

In child-care centres, the influence of caregivers on the development of peer interactions seems ambivalent and mixed results are reported in the literature. Adopting an environmental approach, we examined the effects of the caregivers’ spatial proximity on children's social behaviour. The study was carried out with 175 children (18-40 months) in 12 child-care-centre groups. Children's behaviours were observed during free plays, and both children and caregivers’ locations were recorded. When peers were nearby, children's social behaviours were compared when they were in the immediate proximity (within 2 m) and out of the immediate proximity of a caregiver. Results show that in the latter situation children spend substantially more time addressing social overture to peers and interacting with them; positive interactions with peers show a particularly marked difference. This pattern of results is exhibited by the greater part of the children. Whatever the child-care-centre group, the age subgroup or the gender considered similar results are found. Results also demonstrate that when children are in the immediate proximity of caregivers they are socially oriented towards the attractive adult partners rather than towards peers.     

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