An investigation of repetition and language processing in a case of conduction aphasia

A study is reported of a single case of conduction aphasia. A battery of tasks designed to investigate the parameters of the patient's severe repetition deficit is supplemented by tests of several language functions. The results provide extensive information on a wide range of the patient's language abilities and are used to evaluate the adequacy of four models that have been offered to account for conduction aphasia. An argument is made in support of the suggestion that the syndrome of conduction aphasia should be divided into two subgroups based on patients' ability to select and realize phonemes in speech output. It is concluded that the best explanation for the disorder of patients with repetition deficit but without significant speech output problems is the hypothesis that repetition ability is compromised by a pathological limitation of auditory-verbal short-term memory. This hypothesis is extended to account for the pattern of results obtained in the language tasks.     

Right-hemispheric damage and verbal problem solving behavior.

Patients with right-hemisphere damage, who ostensibly have no linguistic impairment, are relatively incapable of solving two-term series problems in which comparative adjectives in the premise and question are antonymic. This finding suggests that such verbal reasoning depends, in part, upon nonlinguistic imaginal processes subserved by the right hemisphere. In this manner, the right hemisphere is often required for the full elaboration of linguistic input.     

Modality-independent impairments in word processing in a deep dyslexic patient

An extensive study of the language abilities of one deep dyslexic patient, B.L., was undertaken. Tests of his ability to comprehend and produce words in the auditory, verbal, and graphic modalities revealed striking similarities in performance across modalities, such that the defining symptoms of deep dyslexic reading also held true for this patient's writing, repetition, and naming. A new dual-deficit model of deep dyslexia is presented which predicts that a variety of “deep dyslexic” syndromes may occur with or without modality-specific impairments.     

Naming in aphasia: Interacting effects of form and function

The naming difficulties of Broca's and anomic aphasics were explored in relation to a recently developed model of the normal mental lexicon which stresses the importance of integrating perceptual and functional information in the act of naming, and equally stresses the inherent vagueness of conceptual categories based on such information. Subjects were shown line drawings of various food containers varying in physical features such as height and width; they were required to select a name for the object from a multiple choice list (cup, bowl, or glass). Prototypical as well as nonprototypical objects were shown. The Broca's aphasics showed relatively normal naming profiles. In contrast, the posterior patients were unable to integrate perceptual and functional information and were insensitive to the fuzzy boundaries between conceptual categories. The results obtained for the posterior patients are interpreted as reflecting an impairment in the underlying conceptual organization of the lexicon rather than retrieval difficulties.     

The semantic deficit hypothesis: Perceptual parsing and object classification by aphasic patients

Many aphasic patients are impaired in their ability to provide or to recognize the names of objects, but little is known about the processing deficits that underlie these difficulties. In this report, a model of object naming/name recognition is proposed, and a prediction is tested concerning one possible functional locus of impairment in name-recognition and object-naming disorders. A subgroup of aphasic patients is found to be impaired in the ability to perform perceptual similarity judgments for pairs of stimulus objects, and to be unable to classify the objects into one of two lexical categories. It is concluded that the classification disorder suffered by these patients results from an impairment at the level of the semantically guided perceptual parsing of objects.     

Dissociation of algorithmic and heuristic processes in language comprehension: Evidence from aphasia

Three groups of aphasic patients, Broca's, Conduction, and Wernicke's, and a nonaphasic patients control group were tested for comprehension of object-relative center-embedded sentences. The sentences were of three types: sentences in which semantic constraints between words allowed the subjects to assign a correct semantic reading of the sentence without decoding the syntax, sentences in which semantic constraints were relaxed and for which a correct reading was only possible with knowledge of syntactic relationships among words, and sentences which described highly improbable events. The subjects' task was to choose which of two pictures captured the meaning expressed in the sentence. Broca's and Conduction aphasics performed near perfectly on sentences where they could use semantic information. Their performance dropped to chance when they had to use syntactic information. These results support a neuropsychological dissociation of heuristic and algorithmic processes based primarily, though not exclusively, on semantic and syntactic information, respectively.     

Cognitive mechanisms in number processing and calculation: evidence from dyscalculia

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 selective impairment of phonological processing: A case study

A case study is reported of an aphasic patient with fluent speech and markedly superior comprehension of written vs. spoken words. Results of extensive testing supported the hypothesis that the patient suffers from a phonological processing deficit that affects performance in all tasks that require the generation of a phonological code. This selective deficit is interpreted as the underlying cause of diverse symptoms such as asyntactic comprehension of written sentences, the commission of spelling errors in writing, and the production of literal paraphasias and neologisms in spontaneous speech. Alternative possibilities for the classification of this patient are discussed.     

Naive beliefs in “sophisticated” subjects: misconceptions about trajectories of objects

University students were asked to solve simple problems about the trajectories of falling objects. A majority of the students revealed a variety of misconceptions about motion. However, the few basic patterns of responses produced by the subjects suggest considerable commonality in the types of naive physical “laws” people develop on the basis of everyday experience with the world.     

Defective stimulus set attention in generalized epilepsy

This study examined auditory selective attention in primary generalized and complex-partial (temporal lobe) epileptics using binaural and dichotic versions of the Continuous Performance Test. The patient groups did not differ from normal controls when only one channel was presented or when divided attention (simultaneously monitoring two channels) was required. However, generalized epileptics had significantly depressed hit rates when directed attention (responding to critical stimuli in only one channel) was required. These results suggest a contribution of brain stem “arousal” mechanisms to stimulus set attention. In addition, right ear perceptual advantages were found on these dichotic monitoring tasks, lending support to the contention that short-term auditory memory and verbal report are not required for the dichotic ear effect.     

Parallel function strategy in pronoun assignment

Subjects completed sentences of the form NP1 aux V NP2 because (but) Pro … (e.g., John may scold Bill because he …) with a reason or motive for the action described. A basic perceptual strategy was hypothesized to underlie the comprehension of these sentences which have a potentially ambiguous pronoun in the subject position of the subordinate clause. It was expected that listeners would interpret the pronoun as being coreferential with the subject NP of the main clause, the NP with the same grammatical function. While this strategy accounted for the major share of the results, semantic factors restricted its use, establishing an interpretation in which the pronoun was coreferential with the object NP of the main clause.     

Decision processes in verifying category membership statements: Implications for models of semantic memory

Current models of semantic memory assume that natural categories are well-defined. Specific predictions of two such models, the Smith, Shoben, and Rips (1974a) two-stage feature comparison model and the Glass and Holyoak (1974/75) ordered search model, were tested and disconfirmed in Experiment I. We propose an alternative model postulating fuzzy categories represented as sets of characteristic properties. This model, combined with a Bayesian decision process, accounts for the results of three additional experiments, as well as for the major findings in the semantic memory literature. We argue that people verify category membership statements by assessing similarity relations between concepts rather than by using information which logically specifies the truth value of the sentence. Our data also imply that natural categories are fuzzy rather than well-defined.     

Cognitive correlates of map-reading ability

The performance of ROTC students on the Relief Format Assessment Test (RFAT) was regressed on psychometric variables and a measure of hemisphericity. Contrary to expectation, it was found that measures of visual-spatial ability and hemisphericity were not good predictors of map-reading ability, whereas the Extended Range Vocabulary and Mathematical Aptitude Tests were significant predictors. Factor analysis of the RFAT indicated the existence of two factors, one tentatively associated with terrain analysis and the other with altitude estimation. Mathematical Aptitude along with Form Board predicted performance on the altitude estimation factor, whereas Extended Range Vocabulary along with Similarities and Institution predicted performance on the terrain analysis factor. These results suggest that at least for our subjects, the solution of map-reading problems is primarily dependent upon verbal-analytic and to a lesser extent upon visual-spatial ability.     

Imagery,propositions, and the form of internal representations

This paper has four major sections: First, we review the basic arguments offered by Pylyshyn (Psychological Bulletin, 1973, 80, 1–24) and others against using imagery as an explanatory construct in psychology. Second, we consider each of these points and find none that speak against any but the most primitive notions of imagery. Third, we review the results of various experiments on imagery. In each case, we compare two explanations of the findings: one which assumes the existence of a surface image manifesting emergent properties, and one which assumes that all internal representations are coded in terms of “abstract propositions.” We find imagery hypotheses to be at least as adequate as those based on propositional representation. Finally, we conclude that debate about the ultimate foundations of internal representation is fruitless; the empirical question is whether images have properties that cannot be derived directly from more abstract propositional structures.     

Assortative marriage and the familiality of cognitive abilities in families of extremely gifted students

The top 1% of the extremely bright students identified by the Study of Mathematically Precocious Youth (Benbow & Stanley, 1980b) were tested along with their parents, using a battery of specifically designed cognitive tests. These students represented the top 0.03% of their age group in intellectual ability. The results showed that the parents were extremely able and resembled one another significantly more than parents in the general population. In addition, the intellectually precocious children resembled their parents to a lesser extent than children of average ability resemble their parents. These results suggest that considerable assortative mating has occurred among the parents of these extremely gifted youth, but that extreme giftedness cannot be predicted reliably solely as a result of the mating of bright parents.     

The virtues of the SDS and its associated typology: A second response to Prediger and Hanson

The author reviews the evidence for the beneficial effects of the Self-Directed Search (SDS), indicates that Hanson and Prediger have misinterpreted the theory, that their evidence is misleading, and that other evidence indicates that males and females of the same type are similar. The virtues of raw scores are summarized. The author recalls some methodological adventures and outlines where we are now in this controversy about the measurement of interests for special groups.     

Short-term memory performance in the absence of phonological coding

These experiments examined the short-term memory performance of an aphasic patient with posterior damage who shows a selective deficit in phonological coding. In recognition memory tests, the patient relied on both visual and semantic coding, and often showed an essentially normal level of accuracy. However, for memory sets consisting of four function words, his performance was quite impaired. Also, his retention of order information was far below that of normal controls. The implications of these deficits in short-term memory for language comprehension and production are discussed.     

Moral judgments and self-presentations

Meehan, Woll, and Abbott (Journal of Research in Personality, 1979, 13, 25–38) have shown that scores on Hogan's Survey of Ethical Attitudes (SEA) are affected by instructions to simulate politically liberal or conservative attitudes. They also found that scores are affected by instructions to present one's self in a socially desirable or undesirable light, and that group ratings of the social desirability of the items could account for as much as 78% of the item response variance. Meehan et al. argue from these data that the SEA is a measure of political attitudes rather that moral judgments, and that the SEA is susceptible to dissimulation in the form of role playing and impression management. The present paper argues that test-taking is a form of self-presentation, identical to what goes on in everyday social interaction; this renders the Meehan et al. findings meaningful rather than problematic. The paper concludes with a discussion of the relationship between personality testing, self-presentation, moral judgments, and political attitudes.     

Structural complexity as a determinant of serial pattern learning

A new methodology extends the study of serial pattern learning to nonhuman organisms by constructing patterns using elements that are both familiar and motivationally meaningful to animals. Two experiments examine the ability of rats to anticipate various quantities of food as measured by running times in a runway when the quantities occur in a serial order. In Experiment 1, a serial monotonic pattern (14-7-3-1-0 food pellets) produced more rapid learning and more accurate anticipation of the various quantities (“tracking”) than a serial nonmonotonic pattern (14-1-3-7-0 food pellets), particularly with respect to the final 0-pellet element. In Experiment 2, the same monotonic pattern generated faster learning and more accurate anticipation of pattern elements than a weakly monotonic pattern (14-5-5-1-0 pellets). Associative explanations including simple excitatory or inhibitory effects, temporal anticipation, reinforcement contrast, and the number and discriminability of pairwise associations are not adequate to account for the data. Rather, the formally defined structural complexity of each pattern adequately predicts its relative difficulty.     

Choice behavior of rats searching for food

The experiments reported here were designed to determine if several general principles drawn from appetitively motivated discrimination experiments in standard laboratory apparatus might also apply to food-searching behavior under more naturalistic conditions. Food-deprived rats searched for food in an open observation area. Choice behavior after finding food and after not finding food was analyzed. In all cases, not finding food in a possible food location was sufficient to direct subsequent search behavior away from that location for the remainder of the day's test. Finding food had variable effects on subsequent choice behavior, depending on the number of locations that actually contained food and the number of days food was in one location before being shifted to another. The results indicate that the rat's search strategy was influenced by food availability and distribution in ways that are predicted by discrimination learning experiments.