Biomedical subjects

S Roodenrys

Publications and source records attributed to S Roodenrys.

6 recordsLinked to original sources

PubMed2000

The effects of stimulus set size and word frequency on verbal serial recall.

Two experiments are reported which examine immediate serial recall for high- and low-frequency words. The words in each list were either repeatedly drawn from the same small pool of candidates (in the closed set conditions) or each word only ever occurred once during the experiment (in the open set conditions). The results consistently show an effect of word frequency but the effect of set size was only apparent for low-frequency words. It is argued that both frequency and set size effects reflect processes concerning the "clean-up" of degraded short-term memory traces.

Adult↗

PubMed2000

Executive processing and attention deficit hyperactivity disorder: an application of the supervisory attentional system.

Children with attention deficit hyperactivity disorder (ADHD) display many behaviors consistent with an underlying deficit in executive processes. This study examines Norman and Shallice's (1986) supervisory attentional system (SAS) as an approximation of executive functioning thought to be impaired in ADHD. Fifteen ADHD children were compared to a clinical control sample of learning disabled (LD) children and control children matched for age, gender, and IQ on a series of tasks designed to tap the functions of the SAS. The tasks assessed either the inhibition of a strongly triggered response (Star Counting Test, Hayling Sentence Completion Test, and the Random Generation Test) or impulsive responding in the absence of strong trigger-schema contingencies (Brixton Spatial Anticipation Test). Analyses revealed that the ADHD group was significantly impaired, in comparison to the LD and control groups, on tasks requiring the inhibition of a strongly triggered response. Further support for the fractionation of the SAS is provided by the differential performance of the groups on these tasks.

Arousal↗

PubMed1997

Word-frequency effects on short-term memory tasks: evidence for a redintegration process in immediate serial recall.

Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-frequency words in short-term memory tasks. Experiment 1 demonstrated effects of word frequency on memory span that were independent of differences in speech rate. Experiments 2 and 3 showed that word frequency has an increasing effect on serial recall across serial positions, but Experiment 4 showed that this effect was abolished for backward recall. A model that includes a redintegration process that operates to "clean up" decayed short-term memory traces is proposed, and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.

Adult↗

PubMed1995

Practitioner review: verbal working memory development and its disorders.

Working memory refers to the systems responsible for the temporary storage and manipulation of information during the performance of cognitive tasks. There is a good deal of evidence that verbal short-term memory functions as a working memory system. We review advances in our understanding of the nature and limitations of verbal short-term memory and the reasons for its development with age, and go on to consider the common association between impairments of verbal short-term memory and other impairments of cognitive development. We conclude by considering the relationship between short-term memory development and cognitive development.

Adolescent↗

PubMed1994

Effects of word frequency and age of acquisition on short-term memory span.

The experiments reported examine the effects of two highly related variables, word frequency and age of acquisition, on short-term memory span. Short-term memory span and speech rate were measured for sets of words which independently manipulated frequency and age of acquisition. It was found that frequency had a considerable effect on short-term memory span, which was not mediated by speech rate differences--although frequency did affect speech rate in one experiment. For age of acquisition, this situation was reversed; there was a small but significant effect of age of acquisition on speech rate, but no effect on memory span. This occurred despite results confirming that the stimuli used in the experiments produce an effect of age of acquisition on word naming. The results are discussed in terms of a two-component view of performance on short-term memory tasks.

Aging↗

PubMed1993

The development of short-term memory span: separable effects of speech rate and long-term memory.

We report an experiment investigating the mechanisms responsible for short-term memory span and its development by examining the relationship between memory span and speech rate for words and nonwords of differing spoken lengths. Linear functions related memory span to speech rate for both words and nonwords in children of different ages. The functions for nonwords had equivalent slopes (interpreted as reflecting a contribution from a speech-based process) but lower intercepts (interpreted as reflecting a contribution from a long-term memory component) than the functions for words. Children in both age groups studied showed evidence of a relationship between speech rate and memory span and part of the difference in memory span between age groups appears to reflect a difference in speech rate. However, there is also evidence that the long-term memory component of memory span shows greater efficiency in older children.

Age Factors↗