Howard Gardner

Neurocognitive enhancement: what can we do and what should we do?

Our growing ability to alter brain function can be used to enhance the mental processes of normal individuals as well as to treat mental dysfunction in people who are ill. The prospect of neurocognitive enhancement raises many issues about what is safe, fair and otherwise morally acceptable. This article resulted from a meeting on neurocognitive enhancement that was held by the authors. Our goal is to review the state of the art in neurocognitive enhancement, its attendant social and ethical problems, and the ways in which society can address these problems.

The role of the right hemisphere in the apprehension of complex linguistic materials

Abstract To secure information on which aspects of linguistic functioning might be mediated by the nondominant hemisphere, a test battery assessing sensitivity to narrational and humorous materials was administered to a population of right-hemisphere-damaged patients, as well as relevant control groups of normal, aging, and aphasic individuals. While elementary linguistic functioning was adequate, the right-hemisphere-injured groups exhibited consistent difficulties in respecting the boundaries of a fictive entity, assessing the plausibility of elements within a story or joke, selecting the appropriate punch line for a joke, and integrating elements of a story into a coherent narrative. Certain elements—specifically emotional content and noncanonical facts injected into a narrative—also posed characteristic difficulties for these patients. The results suggest that, in contrast to the other populations, right-hemisphere patients exhibit special difficulties in processing complex linguistic entities and in utilizing the surrounding context as they assess linguistic messages.

Inference deficits in right brain-damaged patients.

The inferential reasoning ability of right hemisphere-damaged (RHD) patients was tested by presenting pairs of sentences which were to be treated as single, integrated units. The two sentences treated together made one interpretation likely (a correct inference); one of the sentences in isolation encouraged a different interpretation (an incorrect inference). The position of the misleading sentence was systematically varied. Results showed that, in contrast to normal controls, RHD patients have more trouble answering inference questions, especially those concerning incorrect inferences, than answering questions about the factual content of the passages. Also, RHD patients made significantly more errors when the misleading information was contained in the first rather than in the second sentence; this finding indicates that these patients have difficulty revising previously acquired knowledge in light of new information. These results suggest the impairment of several components of normal discourse processing subsequent to right hemisphere brain damage.

The Theory of Multiple Intelligences

The theory of multiple intelligences, developed by psychologist Howard Gardner in the late 1970s and early 1980s, posits that individuals possess eight or more relatively autonomous intelligences. Individuals draw on these intelligences, individually and corporately, to create products and solve problems that are relevant to the societies in which they live (Gardner, 1983, 1993, 1999, 2006b, 2006c). The eight identified intelligences include linguistic intelligence, logical-mathematical intelligence, spatial intelligence, musical intelligence, bodily-kinesthetic intelligence, naturalistic intelligence, interpersonal intelligence, and intrapersonal intelligence (Gardner, 1999). According to Gardner’s analysis, only two intelligences – linguistic and logical mathematical – have been valued and tested for in modern secular schools; it is useful to think of that language-logic combination as “academic” or “scholarly intelligence.” In conceiving of intelligence as multiple rather than unitary in nature, the theory of multiple intelligences – hereafter MI theory – represents a departure from traditional conceptions of intelligence first formulated in the early 20th century, measured today by IQ tests, and studied in great detail by Piaget (1950, 1952) and other cognitively oriented psychologists.

Surprise but not coherence: Sensitivity to verbal humor in right-hemisphere patients ☆

Verbal humor deficits were investigated in right-hemisphere-damaged patients. It was hypothesized that the appreciation of jokes presupposes two elements: sensitivity to the surprise element entailed in the punch line of a joke and apprehension of the coherence which results when the punch line has been integrated with the body of the joke. The possible dissociation between these elements was tested by asking subjects to select from four alternatives the appropriate ending to a joke. Right-hemisphere patients exhibited a selective attraction to endings which contained an element of surprise but which were not otherwise coherent with the body of the joke. This finding suggests that right-hemisphere patients have difficulty in integrating content across parts of a narrative and confirms the psychological reality of the proposed distinction between the surprise and coherence elements of humor processing.

Sensitivity to emotional expressions and situations in organic patients.

While numerous lines of investigation indicate the pivotal role of the right hemisphere in the apprehension and processing of emotional information, the specific contributions of facial recognition, other visual-spatial capacities, and a general understanding of emotionally-toned situations remains to be delineated. To secure information on the contributions of these various factors, matched groups of brain-damaged patients were required in a series of tests to match with one another faces of the same individual, facial expressions, pictorial versions of emotional situations, and linguistic versions of emotional situations. While patients with left-hemisphere damage evinced special difficulty with linguistically-presented stimuli, patients with right hemisphere damage exhibited an across-the-board reduction in emotional sensitivity, one not restricted to stimuli presented in the visual modality. In addition, right hemisphere patients also displayed a selective tendency to group together emotions of an opposite polarity (positively-toned with negatively-toned emotions). These results suggest that, in addition to its general importance in a range of emotional tasks, the right hemisphere is crucial for an appreciation of the structural relations which obtain among various emotions.

Comprehension of humorous and nonhumorous materials by left and right brain-damaged patients.

Right hemisphere-damaged (RHD) and left hemisphere-damaged (LHD) aphasic patients were tested on a nonverbal cartoon completion task that included a humorous (Joke) and a nonhumorous (Story) condition. In both conditions, RHD patients performed worse than LHD patients. More importantly, the qualitative difference between the errors produced by the two groups suggests that right and left hemisphere brain damage impairs different components of narrative ability. RHD patients showed a preserved sensitivity to the surprise element of humor, and a diminished ability to establish coherence. Conversely, LHD patients, when they erred, showed an impaired sensitivity to the surprise element of humor, and a preserved ability to establish coherence by integrating content across parts of a narrative. These results suggest that the observed humor comprehension deficits of RHD patients result specifically from right hemisphere disease and not from brain damage irrespective of locus. The performances of the RHD and LHD patients groups together support a separation of narrative ability from the traditional aspects of language ability typically disrupted in aphasia.

Sensitivity to lexical denotation and connotation in brain-damaged patients: A double dissociation? ☆

Sets of words can be grouped in terms of their denotation (cold and warm both refer literally to temperature) or in terms of their connotation (cold and warm connote remoteness and intimacy, respectively). To assess whether these two facets of meaning are dissociable, unilaterally left- and right-hemisphere-damaged patients were presented with word triads and asked to group together the two words that were closest in meaning. Right-hemisphere-damaged patients showed a preserved sensitivity to denotation, and a selective insensitivity to connotative facets of meanings. In contrast, left-hemisphere-damaged patients exhibited a preserved sensitivity to connotation as well as a selective insensitivity to denotative aspects of meanings. Inasmuch as normal control subjects displayed a flexible sensitivity to both denotative and connotative aspects of meaning, the results suggest that unilateral brain damage selectively curtails use of one or the other major aspect of word meaning.

The relation between gesture and language in aphasic communication

Abstract Effective communication in aphasia depends not only on use of preserved linguistic capacities but also (and perhaps primarily) on the capacity to exploit alternative modalities of communication, such as gesture. To ascertain the capacity of aphasic patients to use gesture in their spontaneous communication, informally structured interviews were conducted with two Wernickes aphasics and two Brocas aphasics, as well as with four normal controls. The performances of the patient groups were compared on the physical parameters of gesture, the points in the communication where gestures occurred, and several facets of the semantics and pragmatics of gesture. Generally speaking, the gestures of the aphasics closely paralleled their speech output: on most indices, the performance of the Wernickes aphasics more closely resembled that of the normal controls. Wernickes aphasics differed from normals in the clarity of their language and gestures: While individual linguistic units were often clear, the relation among units was not. In contrast, the Brocas aphasics equaled or surpassed the normal controls in the clarity of their communications. The results offer little support for the view that aphasic patients spontaneously enhance their communicative efficacy through the use of gesture; these findings can, however, be interpreted as evidence in favor of a “central organizer” which controls critical features of communication, irrespective of the modality of expression.

Visual communication in aphasia

Abstract Aphasic patients who possessed little or no ability to communicate using natural language were taught a visual communication system (VIC). At issue on a theoretical level was wheter those cognitive operations entailed in natural language may persist in the face of destruction of natural language capacities. Of practical interest was whether severely aphasic patients could communicate effectively using an alternative symbol system. The program included two levels of communicative functions. At Level 1, patients carried out commands, answered questions, and described actions; at Level 2, patients employed the system spontaneously to express their desires and feelings. Of 8 patients given sufficient opportunity to master VIC, 5 completed Level 1, and 2 of these also satisfied the criteria for Level 2. Among these 5 patients, performance in VIC far surpassed performance on matching tasks in English; error rates were quite low; the pattern of errors was remarkably similar; an inverse correlation obtained between ability at English and ability at VIC. The evidence suggests that some severely aphasic patients can master the basics of an alternative symbol system. Moreover several indices suggest that the communicative consequences of the system are appreciated, and that at least some of the cognitive operations entailed in natural language persist despite severe aphasia.