Biomedical subjects

M C Lovett

Publications and source records attributed to M C Lovett.

4 recordsLinked to original sources

PubMed2001

Awareness and working memory in strategy adaptivity.

To further the understanding of the mechanisms of strategy choice, in three experiments, we investigate the role of explicit awareness and working memory in strategy adaptivity. Experiment 1 provided correlational evidence that individual differences in strategy adaptivity to changing base rates are related to individual differences in awareness of those changes but appear not to be related to individual differences in working memory capacity. Experiment 2 replicated the role of awareness, and the results suggest that awareness at the time of the base-rate change, rather than afterwards, is related to increased strategy adaptivity. Experiment 3 measured working memory capacity using a different procedure and manipulated working memory load with a dual-task procedure; again, no apparent role of working memory capacity in strategy adaptivity was found. This juxtaposition of findings presents a challenge for existing models of strategy choice.

Adaptation, Psychological↗

PubMed2000

The importance of frameworks for directing empirical questions: reply to Goodie and Fantino (2000).

A. S. Goodie and E. Fantino (2000) make two main criticisms of the predictions of M. C. Lovett and C. D. Schunn's (1999) RCCL model. (RCCL is pronounced "ReCyCLe"; it stands for Represent the task, Construct a set of action strategies, Choose from among those strategies according to success rate, Learn new success rates.) In both cases, the authors believe the criticisms reflect a failure to appreciate the difference between broad frameworks and specific mathematical/computational models. In this article, the value of a broad framework, such as RCCL, in directing new empirical analyses and guiding theoretical development is shown. In particular, RCCL expands on existing work to reveal how variability and change in mental representations influence base-rate sensitivity. The authors also address several other issues raised by A. S. Goodie and E. Fantino (2000) and show that qualitative shifts in individuals' choice behavior are present in their original data--a key prediction of RCCL that does not appear in previous accounts.

Decision Making↗

PubMed1994

Effects of solving related proofs on memory and transfer in geometry problem solving.

Three experiments investigate the relationship between memory and problem solving in the domain of geometry theorem proving. In Experiment 1, Ss memories for an original problem-solving episode were interfered with retroactively by solving a 2nd problem that had the same diagram, but no memory effects were observed that depended on the second problem's logical similarity to the original. Results suggest that the diagram is the basis for geometry problem-solving memories. Experiments 2 and 3 investigated problem-solving memories in use by examining Ss transfer to a 3rd (test) problem. As with the memory results, transfer was reduced when the 1st two problems had the same diagram relative to when they had 2 different diagrams. Transfer was reduced most in the condition with the greatest proportion of memory-interfering steps. Results suggest that the structure and quality of problem-solving memories affect problem-solving transfer.

Adult↗

PubMed1994

Respiratory function after injection sclerotherapy of oesophageal varices.

Arterial oxygen tension (Pao2), carbon dioxide tension (PaCO2), and vital capacity were measured preoperatively and one day postoperatively in patients with chronic hepatic cirrhosis having elective oesophageal injection sclerotherapy under general anaesthesia. The results were compared with the same measurements made in patients with chronic cirrhosis anaesthetised and scheduled to have injection sclerotherapy under general anaesthesia but who, because of variceal obliteration, only had an oesophagogastroscopy. In the injected group PaO2 decreased by 9.3 (3.0) mm Hg (1.2 (0.4) kPa) (mean (SEM)) (p < 0.02) but in the controls did not change. The difference between the two groups was significant (p < 0.02). Vital capacity decreased by 0.39 (0.08) litres (BTPS) (p < 0.01) after injection sclerotherapy but in the controls did not change. Again the difference between the two groups was significant (p < 0.02). In the injected group there was a significant correlation between the change in PaO2 and the percentage change in vital capacity (r = 0.787, p < 0.01) but no such relation was seen in control subjects. These results suggest that oesophageal injection sclerotherapy is associated with a restrictive defect in respiratory function one day after the injection caused, possibly, by sclerosant embolising to the lung.

Esophageal and Gastric Varices↗