Biomedical subjects
Publications and source records attributed to M McCloskey.
This article describes a theory-based approach to assessment of acquired dyscalculia. A model of the normal cognitive number-processing/calculation system is presented, and methods are discussed for characterizing number-processing/calculation deficits in terms of functional damage to the mechanisms specified in the model.
In this article, we present data from two brain-damaged patients with calculation impairments in support of claims about the cognitive mechanisms underlying simple arithmetic performance. We first present a model of the functional architecture of the cognitive calculation system based on previous research. We then elaborate this architecture through detailed examination of the patterns of spared and impaired performance of the two patients. From the patients' performance we make the following theoretical claims: that some arithmetic facts are stored in the form of individual fact representations (e.g., 9 x 4 = 36), whereas other facts are stored in the form of a general rule (e.g., 0 x N = 0); that arithmetic fact retrieval is mediated by abstract internal representations that are independent of the form in which problems are presented or responses are given; that arithmetic facts and calculation procedures are functionally independent; and that calculation algorithms may include special-case procedures that function to increase the speed or efficiency of problem solving. We conclude with a discussion of several more general issues relevant to the reported research.
Retrieval of basic arithmetic facts is a central aspect of almost any arithmetic performance. Furthermore, the arithmetic facts provide an opportunity to study memory processes in the context of a naturally occurring but circumscribed set of facts. This article examines current models of arithmetic fact retrieval in light of previously reported data from normal subjects, as well as the results from brain-damaged patients reported by Sokol, McCloskey, Cohen, and Aliminosa (1991) in the preceding article. The discussion serves to delineate the strengths and limitations of the models and, more generally, to identify important theoretical and empirical issues in the study of arithmetic fact retrieval.
Explore the source record for details and available documents.
In several recent articles we have developed a model of the cognitive number-processing and calculation systems. Campbell and Clark (1988), commenting on one of these articles (McCloskey, Sokol, & Goodman, 1986), called into question our model's assumption of a modular functional architecture and a single form of internal numerical representation. Campbell and Clark proposed as an alternative a nonmodular encoding-complex view. In this reply we discuss the results offered by Campbell and Clark as evidence against our model, arguing that several of these results are in fact consistent with the model and that the remaining results, while raising significant issues, by no means justify abandonment of the modular framework and the constraints it imposes. We also point out that whereas our model provides specific, well-motivated interpretations for a substantial body of empirical findings, the encoding-complex view is so underspecified and unconstrained as to be vacuous.
We have studied the ability of human peripheral blood mononuclear cells (PBMC) to produce interferon-alpha (IFN-alpha) and IFN-gamma in the presence of pharmacologic agents known to influence calcium transport or calcium-dependent processes. We have found that the production of human (Hu) IFN-gamma is affected significantly by alterations in calcium flux; however, this influence is dependent upon the nature of the compound used to induce IFN. Inhibitors of protein kinase C decreased yields of IFN-gamma but inhibition of calmodulin did not. The presence of vitamin D3 reduced IFN-gamma titers when PHA and IL-2 were used to induce IFN, but not when ionomycin was used as the inducer. The production of IFN-gamma by PBMC was reduced by diminished concentrations in extracellular calcium but not extracellular magnesium. In contrast, neither the presence of any of the pharmacological agents tested above nor the reduction of the calcium concentration influenced the production of HuIFN-alpha by PBMC.
This article presents a model of the cognitive processes involved in the spoken production of verbal numbers (e.g., thirteen thousand four hundred two). On the basis of single-case studies of two brain-damaged subjects with number production deficits, we argue that verbal-number production involves the generation of a syntactic frame that constitutes a plan for the production of the appropriate sequence of words. The syntactic frame specifies each to-be-retrieved word in terms of a number-lexical class (i.e., ones, teens, or tens) and a position within that class. These class/position-within-class specifications guide the retrieval of lexical representations from a production lexicon that is partitioned into functionally distinct ones, teens, and tens classes. We conclude with a brief discussion of the rationale for, and advantages of, using patterns of impaired performance as a basis for drawing inferences about normal cognition.
This article presents a framework for the cognitive analysis of number processing and calculation. Within this framework the primary objective is the development of a model that is sufficiently detailed to serve as a basis for explaining the number-processing/calculation performance of both normal and cognitively impaired subjects. First a general model of the cognitive mechanisms for number processing and calculation is outlined. It is shown that patterns of impairments observed in brain-damaged patients support the major assumptions of the model and that the model provides a theoretically motivated framework for interpreting the deficits. A single case is then discussed in some detail, to demonstrate that through detailed analyses of impaired performance the preliminary model can be elaborated to specify not only the general architecture of the number-processing and calculation systems, but also the inner workings of specific components and the consequences of damage to these components. The article concludes with a discussion of several general issues arising from the presented arguments.
The claim that a person's memory for an event may be altered by information encountered after the event has been influential in shaping current conceptions of memory. The basis for the claim is a series of studies showing that subjects who are given false or misleading information about a previously witnessed event perform more poorly on tests of memory for the event than subjects who are not misled. In this article we argue that the available evidence does not imply that misleading postevent information impairs memory for the original event, because the procedure used in previous studies is inappropriate for assessing effects of misleading information on memory. We then introduce a more appropriate procedure and report six experiments using this procedure. We conclude from the results that misleading postevent information has no effect on memory for the original event. We then review several recent studies that seem to contradict this conclusion, showing that the studies do not pose problems for our position. Finally, we discuss the implications of our conclusions for broader issues concerning memory.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Several recent studies in which subjects solved pencil-and-paper problems concerning the behavior of moving objects have shown that many people have incorrect beliefs about motion. The present study considers the question of whether these naive beliefs are manifested in situations where people observe and interact with moving objects. Several findings in the problem-solving literature suggest that abstract or unrealistic tasks may fail to tap knowledge and reasoning abilities that are routinely used in more concrete or realistic situations. Thus, most people may have accurate knowledge about the behavior of moving objects, knowledge that they use in their everyday interactions with objects in motion. However, this knowledge may not be activated in the context of abstract, static problems, and as a result people attempting to solve such problems may resort to naive beliefs. Three experiments examine this possibility in the context of one specific naive belief, the curvilinear impetus belief. Contrary to expectations, results suggest that the curvilinear impetus belief is used not only on pencil-and-paper problems but also in situations where people observe and interact with moving objects. Implications of these findings are discussed.
This study examines the nature and origin of a common misconception about moving objects. We first show through the use of pencil-and-paper problems that many people erroneously believe that an object that is carried by another moving object (e.g., a ball carried by a walking person) will, if dropped, fall to the ground in a straight vertical line. (In fact, such an object will fall forward in a parabolic arc.) We then demonstrate that this "straight-down belief" turns up not only on pencil-and-paper problems but also on a problem presented in a concrete, dynamic fashion (Experiment 1) and in a situation in which a subject drops a ball while walking (Experiment 2). We next consider the origin of the straight-down belief and propose that the belief may stem from a perceptual illusion. Specifically, we suggest that objects dropped from a moving carrier may be perceived as falling straight down or even backward, when in fact they move forward as they fall. Experiment 3, in which subjects view computer-generated displays simulating situations in which a carried object is dropped, and Experiment 4, in which subjects view a videotape of a walking person dropping an object, provide data consistent with this "seeing is believing" hypothesis.
In order to study the characteristic signs of an induced estrus in beef cattle maintained in the tropics, 31 animals, 16 pure Charolais and 15 Charolais/Brahman cross, were continuously observed during the first 100 hours following prostaglandin injection. The animals were pastured in a field of approximately 3 hectares. A highly significant relationship (P < 0.01) seemed to exist between behavioural tendencies and the interval following the onset of estrus. Behaviour included butting, attempts to mount, smelling of genitalia (active) and allowing to be mounted and have genitalia smelled (passive). No consistant pattern of sexual activity could be established since some animals were more active than others. Mounts were observed to occur between 6 and 9 in the morning (33%), 9 and 12 at night (16%) and midnight and three in the morning (13%). Differences existed between the Charolais and the Brahman cross with respect to the number of mounts (P < 0.05) and in the response to an induced estrus (P < 0.05). No correlation was found between grazing habits and sexual activity, the former expressed as the number of animals standing up during each hour.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
When a target figure is moved back and forth behind a window cut in an opaque screen, more of the figure is seen at a given instant than is physically present. This finding implies that the information presented at one instant is stored in iconic form so that it can be integrated with information presented at a slightly later instant. Two experiments explored the illusion and showed that it can be readily demonstrated under a variety of conditions. A third experiment indicated that it can occur in the absence of appreciable eye movements. This latter finding, together with various supporting argument, is taken as evidence against an explanation of the illusion in terms of the target image being painted across the retina. Rather, it appears that successive sections of the target item are projected onto the same retinal sector. It is difficult to understand how simple photoreceptors can simultaneously retain information presented at one instant and register information presented at a subsequent time without two pieces of information being fused. Therefore, it is concluded that the iconic storage implied by the illusion occurs at a level more central than that of the retinal receptors.
BACKGROUND: Respiratory disease is the major cause of morbidity and mortality in cystic fibrosis (CF). The significance of Burkholderia cepacia (B. cepacia) in the pathogenesis of lung disease in CF is debated, but its exact role remains unclear. AIM: To assess the impact of respiratory tract colonisation with B. cepacia in patients with CF by measuring changes in pulmonary function and body mass index (BMI). METHODS: Three groups of patients were defined based on sputum culture isolates: Group 1 were B. cepacia and Pseudomonas aeruginosa (P. aeruginosa) positive patients; Group 2 were P. aeruginosa positive; and Group 3 were colonised with neither organism. Forced expiratory volume (FEV) and BMI were measured annually from 1987 to 1995 and the year of acquisition of P. aeruginosa or B. cepacia was recorded. RESULTS: The mean annual decrease in FEV1 was significantly different in all three groups: Group 1, -5.4 (5.1)%; Group 2, -3.9 (6.5)%; and Group 3, -1.6 (1.0)%, (p<0.05). The mean percentage decrease in FEV1 of a sub-group of Group 1 patients where the B. cepacia acquisition date was known was 6.1% per year versus 1.55% in Group 2 patients (p<0.05). CONCLUSIONS: Acquisition of B. cepacia may be a cause of, rather than a marker for, a decrease in pulmonary function.