Biomedical subjects

Rachel Barr

Publications and source records attributed to Rachel Barr.

3 recordsLinked to original sources

PubMed2003

The role of sensory preconditioning in memory retrieval by preverbal infants.

Infants' memories are highly specific to their training stimuli; they rarely transfer learned responding. In two experiments, we asked whether sensory preconditioning facilitates the transfer of deferred imitation. In Experiments 1A and 1B, 6-month-olds were simultaneously preexposed to Puppets A and B and then saw target actions modeled on Puppet A. The infants associated the paired puppets and imitated the actions on Puppet B. In Experiment 2, the preexposure procedure was repeated, but the actions were modeled on Puppet A with a toy train in view. The infants also associated Puppet A and the train: Either object effectively reactivated both forgotten memories; thereafter, the infants again imitated the actions on Puppet B. These findings reveal that infants form specific and enduring associations between stimuli they have merely seen together. These associations facilitate the transfer of deferred imitation, both directly and indirectly, through connections to other associations.

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PubMed2002

Bidirectional priming in infants.

In associative priming, the direct activation of one concept indirectly activates others that are associated with it, depending on the directionality of the association. We asked whether associative priming in preverbal infants is bidirectional. Infants associated a puppet imitation task with an operant train task by watching an adult model target actions on the puppet in the incidental context of the train. Later, priming of the forgotten memory of the train task reactivated the infants' memory of the puppet task (Experiment 1), and priming of the infants' forgotten memory of the puppet task reactivated their memory of the train task (Experiment 2). The finding that associative priming was bidirectional offers new insights into the nature of the mnemonic networks formed early in infancy. Additionally, the fact that the present association was formed rapidly and incidentally suggests that a fast mapping, general learning mechanism, like that posited to mediate word-object learning, was responsible for its encoding.

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PubMedDate not supplied

The effect of prior practice on memory reactivation and generalization.

Three experiments examined the effect of practice on memory performance by 18-month-old infants. Infants were tested using an imitation paradigm; an adult demonstrated a series of actions with objects and infants were given the opportunity to reproduce those actions following a delay. Some infants practiced the target actions before the retention interval (practice) and some did not (no practice). In Experiment 1, a reminder treatment alleviated forgetting by infants who practiced but failed to alleviate forgetting by infants who did not practice. In Experiments 2A and 2B, infants who practiced generalized to novel test stimuli after a 24-hr delay, whereas infants without practice did not. Results suggest practice influences the accessibility and generality of infants' memories.

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