Biomedical subjects

Birgit Elsner

Publications and source records attributed to Birgit Elsner.

6 recordsLinked to original sources

PubMed2006

Infants' imitation of goal-directed actions: the role of movements and action effects.

This paper reviews studies on infants' imitation of goal-directed actions in the first two years of life. Special emphasis is given to the role of the two observable components of an action, that is, the movement and the action effects, on infants' replication of target actions. The reviewed studies provide evidence that infants benefit most from a full demonstration of both movements and effects. If movements are demonstrated in isolation, infants may encode this information, but they preferentially reproduce actions that lead to salient effects. If action effects are presented in isolation, infants younger than 19 months usually fail to emulate the unseen movements that would be necessary to produce these effects. Infants' ability to predict action effects or to infer unseen movements from incomplete demonstrations improves substantially at the end of the second year of life. It is concluded that the capability to learn relations between movements and action effects by observation, and the knowledge about movement-effect relations acquired so far, may be important factors underlying the developmental changes in infants' imitation of goal-directed actions.

Goals↗

PubMed2006

Physiological and behavioral parameters of infants' categorization: changes in heart rate and duration of examining across trials.

This report investigates the relations between duration of examining and heart rate (HR) across several trials of an object-examination task. A total of N= 20 11-month-olds were familiarized with a sequence of 10 different exemplars from the same global category (animals or furniture) before they received an exemplar from the contrasting category at test. Consistent with previous findings, HR was lower during states of focused attention (i.e. examining) than during states of casual attention (i.e. looking) or non-looking. Over the familiarization trials, examining stayed about the same, while mean HR increased. At test, examining increased and mean HR decreased, indicating that infants focused their attention on the out-of-category object. Psychophysiological and behavioral measures of attention were systematically related over trials, suggesting that heart rate provides a suitable objective measure to study infants' categorization performance in object-examination tasks.

Attention↗

PubMed2003

Contiguity and contingency in action-effect learning.

According to the two-stage model of voluntary action, the ability to perform voluntary action is acquired in two sequential steps. Firstly, associations are acquired between representations of movements and of the effects that frequently follow them. Secondly, the anticipation or perception of an acquired action effect primes the movement that has been learnt to produce this effect; the acquired action-effect associations thus mediate the selection of actions that are most appropriate to achieve an intended action goal. If action-effect learning has an associative basis, it should be influenced by factors that are known to affect instrumental learning, such as the temporal contiguity and the probabilistic contingency of movement and effect. In two experiments, the contiguity or the contingency between key presses and subsequent tones was manipulated in various ways. As expected, both factors affected the acquisition of action-effect relations as assessed by the potency of action effects to prime the corresponding action in a later behavioral test. In particular, evidence of action-effect associations was obtained only if the effect of the action was delayed for no more than 1 s, if the effect appeared more often in the presence than in the absence of the action, or if action and effect were entirely uncorrelated but the effect appeared very often. These findings support the assumption that the control of voluntary actions is based on action-effect representations that are acquired by associative learning mechanisms.

Adult↗

PubMed2003

The role of action effects in infants' action control.

In adults, the selection and the planning of actions are influenced by the anticipation of desired action effects. However, the role of action effects for action control in infants is still an unresolved issue. One important prerequisite for infants' action control is that infants are able to relate certain movements to certain effects. To test this assumption, it was investigated how infants' action control is affected by action effects. By applying an imitation paradigm, we studied 12- and 18-month-old infants who first observed an adult experimenter demonstrating a three-step action sequence on a toy bear. In three experimental groups, the second action step, the third action step, or no action step elicited an arbitrary sound as an additional acoustic action effect. It was coded how often each of the target actions was performed by the infant in a subsequent 90-s test phase. As predicted, the frequency of the infant's target action varied depending on which action step elicited the action effect. In both age groups, the target action that was combined with an acoustical effect was not only produced more often but also occurred with lower latency and was in most cases the first target action shown by the infants. These results are interpreted as evidence of the important role of action effects in infants' action control.

Female↗

PubMed2003

Do I get what you get? Learning about the effects of self-performed and observed actions in infancy.

The present study investigated whether infants learn the effects of other persons' actions like they do for their own actions, and whether infants transfer observed action-effect relations to their own actions. Nine-, 12-, 15- and 18-month-olds explored an object that allowed two actions, and that produced a certain salient effect after each action. In a self-exploration group, infants explored the object directly, whereas in two observation groups, infants first watched an adult model acting on the object and obtaining a certain effect with each action before exploring the objects by themselves. In one observation group, the infants' actions were followed by the same effects as the model's actions, but in the other group, the action-effect mapping for the infant was reversed to that of the model. The results showed that the observation of the model had an impact on the infants' exploration behavior from 12 months, but not earlier, and that the specific relations between observed actions and effects were acquired by 15 months. Thus, around their first birthday infants learn the effects of other persons' actions by observation, and they transfer the observed action-effect relations to their own actions in the second year of life.

Adult↗

PubMed2002

Linking actions and their perceivable consequences in the human brain.

Voluntary action is goal-directed and therefore depends on the ability to learn associations between movements and their perceivable consequences. The neural substrate of this ability was investigated with H2(15O) positron emission tomography (PET). Healthy adults first learned that self-initiated keypresses were consistently followed by certain tones (i.e., action effects). During PET imaging, participants listened to varied ratios of action-effect tones and neutral tones without performing any movement. The caudal supplementary motor area and the right hippocampus increased their activity with the frequency of action-effect tones, suggesting that both cortical areas play a role in linking the consequences of an action and the action itself. This integration process represents a highly flexible mechanism that helps to promote the learning, automatization, and control of voluntary

Acoustic Stimulation↗