Donald V. DeRosa

Retrieval of information from organized memory sets

The purpose o f this study was to investigate the biological effects of saccharin ingestion on serum FFA and blood glucose levels in rats. Analysis of the data revealed a statistically significant effect on serum FFA levels, but not on blood glucose levels. The results also indicate that the effect is influenced by previous experience and the degree of water deprivation.A recognition reaction time (RT) investigation examined retrieval of individual elements from memorized sets of digits. The sets varied in organization and the delay between presentation of the items, and a recognition test was systematically manipulated. Organized sets produced faster reactions then unorganized sets. Serial position effects were less pronounced and operative for a shorter period of time with organized material.

Retrieval of information from multiple ensembles in short-term memory

A recognition memory experiment investigated Ss’ ability to organize information in short-term memory. A paradigm similar to that used by Sternberg was employed. A sequentially presented series of six digits (positive set) was shown with each digit appearing on a red, green, or amber background. The colors defined different ensembles, and responding to a test digit was contingent upon an item’s membership in the positive set and the color-defined ensemble. Reaction time (RT) to the test digits indicated that Ss did organize information into ensembles. Furthermore, when informative cues were presented prior to the test item, Ss directed and confined their search to the cued subset.

Categorical encoding in short-term memory by 4- to 11-year-old children

One hundred and sixty children, ages 4 to 11, were tested in a STM task similar to that used by Wickens, Born, &Allen (1963). Special interest focused on the buildup and release of proactive interference (PI). All age groups show PI when conceptual categories (toys or kitchen utensils) were the to-be-remembered items. In addition, all groups which shifted to a different conventional category on the last trial, show release from PI. The theoretical significance of the presence of PI and its release in preschool children is discussed.

Memory scanning of young and old adults: The influence of rate of presentation and delay interval on recognition memory performance

The present study investigated memory scanning of 12 young (mean age = 19.0 years) and 12 old (mean age = 67.7 years) subjects. Reaction times were measured in a recognition memory task developed by Sternberg (1966), using a variety of presentation conditions. The mean scanning rates for young and old subjects were similar to those obtained in previous research when slow rates of presentation were used. However, with rapid rates of presentation, older subjects do just as well as young subjects. An examination of individual subjects’ data indicated that 9 of the 12 old subjects scanned at much the same rate as the young subjects even when slow rates were used, whereas the remaining 3 subjects scanned much more slowly than all others in both age groups.

Scanning organized material: Individual differences in search strategies

A recognition memory experiment investigated memory scanning of material with varying degrees of organization. Subjects were shown a series of three, four, or five digits (positive set) followed by a probe stimulus in a paradigm developed by Sternberg (1966). The results indicated that, for unorganized positive sets, all subjects performed a serial search, with reaction time increasing across set size. For highly organized sets, some subjects continued to perform a serial search, while others engaged in a unit search, evidenced by the fact that reaction time was not related to set size. These two groups also differed in their overall response latencies, and a signal detection theory analysis indicated that subjects choosing a serial strategy were more cautious (i.e., more concerned with accuracy) than subjects choosing a unit strategy.

Transformations on sets in short-term memory: Temporal and spatial factors influencing deletion

An individual’s ability to perform a deletion operation on sets in short-term memory was explored in a reaction time (RT) experiment. Special attention was given to the importance, for deletion, of temporal and spatial variables. Ss did perform a deletion operation. The speed of correct recognition was influenced by both the delay between the deletion (D) set and a test item and the serial order correspondence between identical items in the to-be-remembered or positive (P) set and the D set.