Biomedical subjects

Steve W Kelly

Publications and source records attributed to Steve W Kelly.

4 recordsLinked to original sources

PubMed2006

A dual-process account of digit invariance learning.

Performance in the McGeorge and Burton (1990) digit invariance task was originally thought to be mediated by unconscious abstraction of a "rule" that identified the invariant feature across all study items. Subsequent explanations have suggested explicit strategy use or similarity-to-exemplar matching rather than abstraction. This paper presents data that suggest that both similarity and abstraction can be used under different task demands. Delay between study and test afforded abstraction of the invariant knowledge whereas reducing the pool of study exemplars enhanced responding based on specific similarity. These results parallel effects found in the categorization literature. Rule abstraction in this sense may be due to statistical learning of feature frequency rather than abstraction of a central tendency or a complex/conceptual rule. Categorizing responses into subjective memory states (remember/know/guess) demonstrates that neither the similarity matching nor the abstraction mechanism uses information from episodic memory. Confidence measures show that participants are more confident of responses when the prototypical representation is used but not specific similarity. Taken together, these data suggest that abstracted knowledge is not held consciously but that participants have meta-awareness of when they are using the abstracted representation.

Analysis of Variance↗

PubMed2005

An instrument for the non-invasive assessment of lip function during speech.

This paper describes the development of an instrument using infrared light as a non-invasive means of detecting lip opening, the extent of the opening and also the forward protrusion and backward movement of the lips during speech. The design criteria were to build a simple stand alone means of assessing lip function, which could also link to the group's commercially available Super Nasal-Oral Ratiometry System (SNORS+). SNORS+ allows objective assessment of the function and co-ordination of key articulators, with lip function previously monitored using a video camera. Synchronised tests were carried out using the new Lip Function Monitor and the video camera simultaneously, in order to verify that the signals produced related directly to the activity of the mouth. A small trial was then conducted to show that the system provides reproducible results throughout a range of 'normal' subjects. These subjects were of different gender and race to create a sample group within which there was a variety of lip sizes and face shapes. Technical aspects of the instrument and trial results are presented here. These suggest that the simple visual output and feedback of the instrument will prove useful in the assessment and management of speech disorders.

Equipment Design↗

PubMed2004

Learning of ambiguous versus hybrid sequences by patients with Parkinson's disease.

Implicit motor learning as indexed by the serial reaction time (SRT) task has been shown to be impaired in patients with Parkinson's disease (PD). This has only been conclusively demonstrated for sequences that require learning of second-order sequential information (ambiguous sequences). This study examines implicit learning of ambiguous sequences as well as sequences which contain first-order information (hybrid sequences) in a sample of 12 early to middle stage Parkinson's disease patients and matched controls. The study used dual-task methodology in order to prevent strategic/attentional learning of second-order information. The results showed that while ambiguous sequences were not learned by either group, both patient and control groups demonstrated learning of the hybrid sequence under dual-task conditions. This suggests that first-order associations may be learned by people with Parkinson's disease, even under attentionally demanding conditions. This may be interpreted as providing evidence for a non-attentional learning mechanism which is relatively intact in Parkinson's disease.

Aged↗

PubMedDate not supplied

Evidence for implicit sequence learning in dyslexia.

Nicolson and Fawcett (Cognition 1990; 35: 159-182) have suggested that a deficit in the automatization of skill learning could account for the general impairments found in dyslexia. Much of the evidence for their claims has been collected via a dual task paradigm, which might allow for alternative explanations of the data. The present study examines automatic skill learning in a single task paradigm and extends previous studies by independently examining the contribution of stimulus-based and response-based learning. The task replicates Mayr's (J. Exp. Psychol.: Learning Memory Cognition 1996; 22: 350-364) methodology in the Serial Reaction Time task by exposing participants to two structured displays, simultaneously. Learning is measured by comparing RT to the learned sequence against RT to a random display. This study demonstrates learning for both dyslexic and control groups for a spatial sequence which was observed and a concurrent non-spatial sequence which was responded to via a keypress. Learning of the sequence did not seem to depend on awareness of the sequence structure. These results suggest that automatic skill learning is intact in dyslexic individuals.

Adult↗