The Emergence of Declarative Memory

The Emergence of Declarative Memory

Markas Brunson

The Emergence of Declarative Memory

The following is a summary and evaluation on the research article, The Development of Declarative Memory in Human Infants: Age-Related Changes in Deferred Imitation. The article is based on experiments performed to resolve the issue of the approximate time when declarative memory begins to form and the effect of age has on declarative memory; this experiment was lead by Harlene Hayne, Joanne Boniface, and Rachel Barr, all of the University of Otago in Dunedin, New Zealand. A chief indicator of the achievement of declarative memory is the success of imitation. The use of infants of different age ranges was vital to the study; the infants used were 12 months, 18 months, and 24 months.

To correctly test the declarative memory, the researcher used deferred imitation tasks with the infants. In the first experiment 60 infants were used that were 12 months and 60 infants were used to that were 18 months. Two hand puppets were used, a pink rabbit and a grey mouse; both were about 30 centimeters high and contained a jingle bell which was inside the mitten which was the control condition or either inside the mitten which was the demonstration condition. Infants in both groups participated in a demonstration session and a test session; the test session was separated 24 hours from the demonstration session. During the demonstration session, half of the infants were in their homes and the other half were in a laboratory, a different context. "For infants in the demonstration condition, the experimenter then performed three target actions with the puppet. First, she removed the mitten from the puppet's right hand. Second, she shook the mitten three times, ringing the bell inside. Third, she replaced the mitten on the puppet's right hand. This sequence of actions was then repeated two more times. The entire demonstration session lasted approximately 20-30 s. When the demonstration was complete, the experimenter put the puppet away and the session ended." (Barr, R., & Hayne, H. (2000) The infants in the control session were exposed to the same variables as the infants, but the target actions were never demonstrated; also, the infants were separated in the control condition, half in their homes and the other half in a laboratory. The test session was 24 hours after the demonstration session. The bell was removed and the puppet was 30 centimeters away from the infant instead of the 80 centimeters performed during the demonstration session. In the test session half the infants were tested with the same puppet they tested with in the demonstrations and the other half tested with the other puppet provided. In addition, half of the infants were tested in a different context (laboratory) and the other half tested in their homes; ultimately, four different test groups would originate: a group with the same puppet and context, same puppet and different context, different puppet and same context, and different puppet and different context.

Two observers who were unaware of the infants group assignments scored the infants based on their imitation of the target actions such as the removal of the mitten, shaking of the mitten and the attempt to replace the mitten back on the puppet's hand were observed had an effect on the score. The results were unyielding in information. It seemed that context did not really have an effect on the results for the infants, but the type of puppet had vital effect on the results for the 12 month olds. The 12 month olds had trouble imitating the target actions with a different puppet. The use of different puppets had no effect on the 18 month infants, also their demonstration of the target actions were