Inability of five-month-old infants to retrieve a contiguous object: a failure of conceptual understanding or of control of action?

Attentional capture in goal-directed action during childhood, adolescence, and early adulthood

Attentional capture occurs when salient but task-irrelevant information disrupts our ability to respond to task-relevant information. Although attentional capture costs have been found to decrease between childhood and adulthood, it is currently unclear the extent to which such age-related changes reflect an improved ability to recover from attentional capture or to avoid attentional capture. In addition, recent research using hand-tracking techniques with adults indicates that attentional capture by a distractor can generate response activations corresponding to the distractor's location, consistent with action-centered models of attention. However, it is unknown whether attentional capture can also result in the capture of action in children and adolescents. Therefore, we presented 5-year-olds, 9-year-olds, 13- and 14-year-olds, and adults (N = 96) with a singleton search task in which participants responded by reaching to touch targets on a digital display. Consistent with action-centered models of attention, distractor effects were evident in each age group's movement trajectories. In contrast to movement trajectories, movement times revealed significant age-related reductions in the costs of attentional capture, suggesting that age-related improvements in attentional control may be driven in part by an enhanced ability to recover from-as opposed to avoid-attentional capture. Children's performance was also significantly affected by response repetition effects, indicating that children may be more susceptible to interference from a wider range of task-irrelevant factors than adults. In addition to presenting novel insights into the development of attention and action, these results highlight the benefits of incorporating hand-tracking techniques into developmental research.

Kcnn2 blockade reverses learning deficits in a mouse model of fetal alcohol spectrum disorders

Learning disabilities are hallmarks of congenital conditions caused by prenatal exposure to harmful agents. Those include Fetal Alcohol Spectrum Disorders (FASD) with a wide range of cognitive deficiencies including impaired motor skill development. While these effects have been well characterized, the molecular effects that bring about these behavioral consequences remain to be determined. We have previously found that the acute molecular responses to alcohol in the embryonic brain are stochastic, varying among neural progenitor cells. However, the pathophysiological consequences stemming from these heterogeneous responses remain unknown. Here we show that acute responses to alcohol in progenitor cells alter gene expression in their descendant neurons. Among the altered genes, an increase of the calcium-activated potassium channel Kcnn2 in the motor cortex correlates with motor learning deficits in the mouse model of FASD. Pharmacologic blockade of Kcnn2 improves these learning deficits, suggesting Kcnn2 blockers as a novel intervention for learning disabilities in FASD.

The relation between crawling and 9-month-old infants' visual prediction abilities in spatial object processing

We examined whether 9-month-old infants' visual prediction abilities in the context of spatial object processing are related to their crawling ability. A total of 33 9-month-olds were tested; half of them crawled for 7.6weeks on average. A new visual prediction paradigm was developed during which a three-dimensional three-object array was presented in a live setting. During familiarization, the object array rotated back and forth along the vertical axis. While the array was moving, two target objects of it were briefly occluded from view and uncovered again as the array changed its direction of motion. During the test phase, the entire array was rotated around 90° and then rotated back and forth along the horizontal axis. The targets remained at the same position or were moved to a modified placement. We recorded infants' eye movements directed at the dynamically covered and uncovered target locations and analyzed infants' prediction rates. All infants showed higher prediction rates at test and when the targets' placement was modified. Most importantly, the results demonstrated that crawlers had higher prediction rates during test trials as compared with non-crawlers. Our study supports the assumption that crawling experience might enhance 9-month-old infants' ability to correctly predict complex object movement.

Occlusion is hard: Comparing predictive reaching for visible and hidden objects in infants and adults

Infants can anticipate the future location of a moving object and execute a predictive reach to intercept the object. When a moving object is temporarily hidden by darkness or occlusion, 6-month-old infants' reaching is perturbed but performance on darkness trials is significantly better than occlusion trials. How does this reaching behavior change over development? Experiment 1 tested predictive reaching of 6- and 9-month-old infants. While there was an increase in the overall number of reaches with increasing age, there were significantly fewer predictive reaches during the occlusion compared to visible trials and no age-related changes in this pattern. The decrease in performance found in Experiment 1 is likely to apply not only to the object representations formed by infants but also those formed by adults. In Experiment 2 we tested adults with a similar reaching task. Like infants, the adults were most accurate when the target was continuously visible and performance in darkness trials was significantly better than occlusion trials, providing evidence that there is something specific about occlusion that makes it more difficult than merely lack of visibility. Together, these findings suggest that infants' and adults' capacities to represent objects have similar signatures throughout development.

Occlusion is hard: Comparing predictive reaching for visible and hidden objects in infants and adults

Infants can anticipate the future location of a moving object and execute a predictive reach to intercept the object. When a moving object is temporarily hidden by darkness or occlusion, 6-month-old infants' reaching is perturbed but performance on darkness trials is significantly better than occlusion trials. How does this reaching behavior change over development? Experiment 1 tested predictive reaching of 6- and 9-month-old infants. While there was an increase in the overall number of reaches with increasing age, there were significantly fewer predictive reaches during the occlusion compared to visible trials and no age-related changes in this pattern. The decrease in performance found in Experiment 1 is likely to apply not only to the object representations formed by infants but also those formed by adults. In Experiment 2 we tested adults with a similar reaching task. Like infants, the adults were most accurate when the target was continuously visible and performance in darkness trials was significantly better than occlusion trials, providing evidence that there is something specific about occlusion that makes it more difficult than merely lack of visibility. Together, these findings suggest that infants' and adults' capacities to represent objects have similar signatures throughout development.

A comparison of executive function in very preterm and term infants at 8 months corrected age

BACKGROUND

Executive function (EF) emerges in infancy and continues to develop throughout childhood. Executive dysfunction is believed to contribute to learning and attention problems in children at school age. Children born very preterm are more prone to these problems than their full-term peers.

AIM

To compare EF in very preterm and full-term infants at 8 months after expected date of delivery.

SUBJECTS

37 very preterm infants without identified disabilities, and 74 gender and age matched healthy full-term infants. The very preterm infants were all </=32 weeks gestation and <1250 g birthweight.

OUTCOME MEASURES

EF tasks which measured working memory, inhibition of distraction, and planning at 8 months after expected date of delivery.

RESULTS

The very preterm infants performed significantly more poorly than the full-term infants on all measures of executive function. No significant differences were found between very preterm and full-term infants on any of potentially confounding variables of, infant temperament, maternal education, family income and maternal psychological wellbeing. Very preterm infants had significantly lower scores on the Mental Development Index (MDI) and Psychomotor Development Index (PDI) on the Bayley Scales of Infant Development (BSID II), however when this was partialled out the differences in EF scores remained. Medical complications, lower birthweight and lower gestation age were all found to adversely affect the performance of very preterm infants on executive function tasks.

CONCLUSION

Very preterm infants performed more poorly than full-term infants on measures of EF. Further follow up studies are required to investigate whether EF measures in infancy can predict learning and attention outcome at school age.

Can infants be "taught" to attend to a new physical variable in an event category? The case of height in covering events

As they observe or produce events, infants identify variables that help them predict outcomes in each category of events. How do infants identify a new variable? An explanation-based learning (EBL) account suggests three essential steps: (1) observing contrastive outcomes relevant to the variable; (2) discovering the conditions associated with these outcomes; and (3) generating an explanation for the condition-outcome regularity discovered. In Experiments 1-3, 9-month-old infants watched events designed to "teach" them the variable height in covering events. After watching these events, designed in accord with the EBL account, the infants detected a height violation in a covering event, three months earlier than they ordinarily would have. In Experiments 4-6, the "teaching" events were modified to remove one of the EBL steps, and the infants no longer detected the height violation. The present findings thus support the EBL account and help specify the processes by which infants acquire their physical knowledge.

Young infants' actions reveal their developing knowledge of support variables: converging evidence for violation-of-expectation findings

Violation-of-expectation (VOE) tasks have revealed substantial developments in young infants' knowledge about support events: by 5.5 months, infants expect an object to fall when released against but not on a surface; and by 6.5 months, infants expect an object to fall when released with 15% but not 100% of its bottom on a surface. Here we investigated whether action tasks would reveal the same developmental pattern. Consistent with VOE reports, 5.5- and 6.5-month-old infants were more likely to reach for a toy that rested on as opposed to against a surface; and 6.5- but not 5.5-month-olds were more likely to reach for a toy with 100% as opposed to 15% of its bottom on a surface. Infants at each age thus used their support knowledge to determine whether the toys were likely to be retrievable or to be attached to adjacent surfaces and hence irretrievable. These and control findings extend recent evidence that developmental patterns observed in VOE tasks also hold in action tasks, and as such provide further support for the view that VOE and action tasks tap the same physical knowledge.

Décalage in infants' knowledge about occlusion and containment events: converging evidence from action tasks

In the present research, 6-month-old infants consistently searched for a tall toy behind a tall as opposed to a short occluder. However, when the same toy was hidden inside a tall or a short container, only older, 7.5-month-old infants searched for the tall toy inside the tall container. These and control results (1) confirm previous violation-of-expectation (VOE) findings of a décalage in infants' reasoning about height information in occlusion and containment events; (2) cast doubt on the suggestion that VOE tasks overestimate infants' cognitive abilities; and (3) support recent proposals that infants use their physical knowledge to guide their actions when task demands do not overwhelm their limited processing resources.