Numerical taxonomy of aphasia

Two hundred consecutively seen aphasics, 142 of them with infarcts, were examined by tests of fluency, comprehension, repetition, naming, and information content. The language scores were subjected to a minimum variance clustering algorithm separately for the total and for the infarct groups. The latter generated 10 clusters on a dendrogram. Attribute analysis of each cluster provided a clinically meaningful profile of language performance for these groups. The degree of correlation of most computer generated clusters with clinically recognized groups was high, and the homogeneity of some of the clusters is striking. An exception appears to be “conduction aphasia,” which is bimodally distributed. One of these clusters, with high fluency and low comprehension scores, was renamed “afferent conduction” aphasia, and the other, with lower fluency and higher comprehension, was renamed “efferent conduction” aphasia. The Principal Components Analysis was used to evaluate the discriminatory value of language characteristics, and the Nearest Neighbor Network Analysis was used to evaluate the significance of clustering. The dendrogram for all aphasics showed a less specific and less homogenous six clusters.     

Patterns of spontaneous recovery in aphasic groups: A study of adult stroke patients

The recovery of 31 aphasic stroke patients in the first three months postonset was investigated. Improvements on eight comprehension, repetition, and expression tasks were documented for four groups. These groups, retrospectively defined on the basis of initial scores on a fluency and a comprehension task, were: Low Fluency/Low Comprehension (LFLC), Low Fluency/High Comprehension (LFHC), High Fluency/Low Comprehension (HFLC), and High Fluency/High Comprehension (HFHC). Examination of each group's recovery revealed (1) equal improvement on nearly all language tasks for the two High Comprehension groups and (2) a more selective improvement largely in comprehension and imitation tasks for the two Low Comprehension groups. Implications of this selective improvement in initially low comprehending aphasics are discussed.     

Computer tomographic localization, lesion size, and prognosis in aphasia and nonverbal impairment.

Computerized tomography scans (80) were used to localize infarcts in 70 patients. Twenty-three aphasics were scanned within 35 days from onset, 39 beyond a year, and 18 were nondominant cases. Aphasics were also grouped according to test scores obtained within 35 days of scan. Chronic global aphasics have larger lesions than persisting Broca's aphasics. The area of persisting Broca's aphasia is similarly anterior but larger than that of recovered motor aphasia. Anomic aphasics evolve from Broca's and Wernicke's types with differing localization. Lesion size correlated with severity and recovery, and comprehension among the subtests.     

Remembrance of places lasts: Proactive inhibition and patterns of choice in rat spatial memory

A series of experiments was carried out to evaluate the notion that rats given a sequence of massed daily trials on the radial maze reset working memory at the end of each trial by deleting its contents. Although curves presented by D. S. Olton [Scientific American, 1977, 236, 82–98; In S. H. Hulse, H. Fowler, & W. K. Honig (Eds.), Cognitive processes in animal behavior, Hillsdale, N.J.: Erlbaum, 1978] show that rats return to errorless performance at the beginning of each trial after the first, the fact that accuracy falls less rapidly over choices on Trial 1 than on subsequent trials suggests a proactive inhibition (PI) effect. In Experiment 1, Olton's findings were replicated, and a PI effect was observed on Days 1–2 of testing. On Days 3–5, overall accuracy improved significantly and was associated with the development of a strong tendency for rats to enter adjacent alleys, which became particularly marked on the final trials of a day's testing. In order to prevent rats from achieving accurate performance by using an adjacent alleys pattern, a procedure was used in Experiment 2 which involved initial forced random choices followed by a retention test consisting of free choices. Repeated daily trials with this procedure yielded a significant PI effect, which was more marked at a 60-sec delay than at a 0-sec delay. Experiments 3 and 4 showed this PI effect to be robust and resistant to manipulations designed to produce release from PI. Both the PI effect and a strong tendency found in Experiment 1 for animals to avoid on the initial choices of Trial n those alleys most recently entered on Trial n?1 argue that rats do not reset working memory between trials.     

The influence of flavor preexposure and test interval on conditioned taste aversions in the rat

The effects of flavor preexposure and test interval on conditioned taste aversions were examined in four experiments. In the first three experiments, prior experience with a flavor different from that used as a conditioned-stimulus (CS) produced attenuated aversions when testing occurred after a 1-day interval but not after a 21-day interval. Preexposure to the same stimulus used as a CS produced attenuated aversions at both 1- and 21-day intervals. In Experiment 4, a delay interval between flavor preexposure and conditioning eliminated the attenuating effect of preexposure, but only when different stimuli were used for preexposure and conditioning. These data could not be easily accounted for by contemporary interpretations of preexposure as an event that interferes with subsequent acquisition of a conditioned aversion. An alternative retrieval interference hypothesis was outlined.     

Some effects of lick-contingent delays on the development of schedule-induced polydipsia

Experiments 1 and 2 examined the effects of various durations of lickcontingent delays of reinforcement on the development of schedule-induced polydipsia. Food was provided every 1 min in the absence of licking. Delays of 1 min or more effectively disrupted the development of the licking behavior. In Experiments 3 and 4 a lick-contingent stimulus was provided in addition to the delay of food delivery. A light, which was turned on by a lick and turned off by food, greatly enhanced the development of polydipsia under delays that had previously prevented such development. A tone proved less effective than the light in promoting the development of polydipsia. Adventitious reinforcement and conditioned punishment explanations of these results were considered. A distinction was drawn between the mechanism responsible for the development of schedule-induced behavior and that responsible for its maintenance.     

Spatial memory in rats under restricted viewing conditions

In a procedure devised by J. A. Walker and D. S. Olton (Learning and Motivation, 1979, 10, 73–84), rats were placed on two arms of a four-arm radial maze and then were placed in the center of the maze to test how accurately they could choose the alleys on which they had not been placed. In three experiments, the conditions under which animals viewed the environment from the arms were varied. In Experiment 1, both the extent of spatial view and the exposure time were varied factorially in a within-subjects design; animals viewed the environment down a tunnel or had a 180° or 360° view, and subjects were allowed to view the environment for either 2 or 20 sec. In Experiment 2, a between-subjects design was used, in which different groups of subjects were tested repeatedly under either the tunnel, 180°, or 360° conditions. Both experiments showed that animals could avoid the arms previously visited at no better than a chance level of accuracy in the tunnel viewing condition but could perform with progressively better accuracy at the 180 and 360° viewing conditions. Animals also were more accurate in Experiment 1 after viewing for 20 sec than after viewing for 2 sec. Experiment 3 involved a procedure in which restricted viewing conditions were used both during arm placements and testing. Animals tested under tunnel viewing eventually achieved above-chance performance with this procedure, but did not exceed chance as rapidly as groups tested with 45 and 90° views of the environment. These results suggest that animals can learn about their position in a spatial environment through observation and that an animal's ability to locate its position is directly related to the extent of the surrounding environment it can see and the length of time it is allowed to look. The implications of these findings for list and map hypotheses of spatial memory representation are discussed.     

Impairment of nonlinguistic hand movements in a deaf aphasic

A deaf man who became aphasic for sign language was seen 4 years after a left-hemisphere stroke. While not impaired on traditional apraxia tests, he was impaired, relative to nonaphasic deaf controls, in the imitation of complex nonlinguistic hand movements. He was not impaired on single isolated movements. These findings are interpreted as supporting a concept of left-hemisphere function which emphasizes complex motor control.     

Optimizing the validity of personality assessments: The importance of aggregation and item content

The predictive validity of a psychological measure can be improved by minimizing measurement errors through increases in the length of the assessment (aggregation) and, for an assessment of finite length, by making use of objective strategies for choosing from all available component measures. Two prominent considerations in selecting individual measures to be aggregated involve standards of (a) item content (construct approach) and (b) item/criterion association (empirical approach). Personality trait scales of different lengths were assembled for this study in order to represent features of the construct and empirical methods of selection. It was observed that (a) although reliability and validity generally increased with test length, aggregation beyond a certain point can fail to be expedient; and (b) although the prediction performance of empirically derived measures initially surpassed that of construct based assessments, the superiority of the empirical scales did not generalize to trait criteria that were not used as a basis for item selection. The data are interpreted as providing support for a theory-based program of test development where substantive considerations involving item content play a major role. The findings are also viewed as encouragement for conventional conceptualizations about organized dimensions of behavior.     

The reliability of aggregated measurements: Lessons to be learned from psychometric theory

In a recent article, H. D. Day, D. Marshall, B. Hamilton, and J. Christy (1983, Journal of Research in Personality, 17, 97–109) have reported on a series of simulation studies designed to investigate properties of various coefficients of behavior stability as applied to cross-situational data. The results of their research have prompted them to suggest precautions regarding the measurement of behavioral regularity with conventional indices of response consistency. A critical review of their paper reveals aspects of the data, procedures, and interpretations of Day et al. (1983) which undermine many of their conclusions. Notable problems include (a) inappropriate comparisons of internal consistency reliability coefficients based on nonparallel analyses, (b) anomalous data which may be due to errors of rounding or recording, and (c) the failure to recognize certain assumptions underlying reliability estimation. More importantly, it is shown that the investigation of Day et al. (1983) represents primarily an empirical verification of several measurement principles for which algebraic proofs are amply documented.     

Memory for lists of spatial events in the rat

Three experiments are reported in which rats were presented with lists of spatial events or responses in distinct visual contexts, and retention subsequently was measured for the events occuring at each serial position. In Experiments 1 and 2, lists contained different numbers of forced choices on successively presented T-mazes, and memory for each serial position was tested on each trial. In Experiment 3, lists were made up of different numbers of forced entries into randomly ordered arms on the eight-arm radial maze, and memory for one serial position was probed on each trial. All three experiments yielded serial position curves which demonstrated recency effects but no primacy effects. Comparisons of retention for different list lengths within each experiment indicated that retention of shorter lists was equivalent to retention of the final items of longer lists and superior to retention of the initial items on longer lists. This pattern of results indicated that there was no evidence of proactive inhibition in the serial position curves. Analysis of input and output interference effects and the results of control tests suggested that both retroactive inhibition and time-based forgetting processes were responsible for recency effects.     

Dissonance motivation: Its nature,persistence, and reinstatement

This paper examines whether arousal is a necessary component of the motivation to reduce dissonance. Alternative responses to attitude-behavior inconsistency include attitude change, explaining the behavior by a consonant cognition (i.e., low choice), and attributing the dissonance-induced state to an alternative source, such as the purported side effects of an ingested “drug.” For conditions in which there are few consonant cognitions (i.e., high choice), a comparison of different “drug” conditions in which attitude change does or does not occur was expected to clarify which components of the dissonance-induced state mediate attitude change. Attitude change occurred in high choice conditions where the “drug” was described as pleasant, but not in high choice conditions where the “drug” was described as unpleasant or in a low choice condition. In addition, when the “drug” was descibed as arousing there was, if anything, more attitude change than when the “drug” was described as nonarousing. These results suggest that unpleasantness and not arousal per se is the motivating factor in dissonance reduction. The effects of the passage of time and reinstating the counterattitudinal behavior on the alternative responses to attitude-behavior inconsistency were also examined. Subjects returned 2 weeks later, stated their attitudes, recalled their original counterattitudinal essay, and again stated their attitudes. Although there was a general decrease in attitude change during this period, the pattern of attitude change remained basically the same. Attitude change following reinstatement increased from its original level only in those conditions where it had been initially attenuated through misattribution or a consonant cognition.     

On ad hoc personality scales: A reply to Burisch

Two recent articles by M. Burisch (1984, American Psychologist, 37, 214–227; 1984, Journal of Research in Personality, 18, 81–98) have presented data bearing on the traditional methods by which personality is assessed. Based on a review of selected empirical studies and analyses of new data, Burisch has concluded that (a) single-item global self-ratings generally yield greater coefficients of criterion validity than questionnaire measures of the same traits, and (b) most existing personality questionnaires can be shortened considerably without any consequent loss in validity. These conclusions stand in direct contrast to previous appeals by Epstein and others for the use of extensive aggregate measures of personality derived according to the axioms of psychometric theory. In response to Burisch, we describe measurement artifacts and strategies of test item selection that account for some of his conclusions and we reiterate the need for the application of conventional construct-based questionnaires in the assessment of personality.     

Long-delay taste aversion learning in an unpoisoned rat: Exposure to a poisoned rat as the unconditioned stimulus

M. J. Lavin, B. Freise, and S. Coombes (Behavioral and Neural Biology, 1980, 28, 15–33) have shown that if two rats consume a flavored solution and one is poisoned, the unpoisoned partner will also exhibit a flavor aversion during a later preference test. Experiments 1 and 2 showed that a sufficient condition for obtaining this aversion is that the poisoned partner be present with the unpoisoned rat after it has consumed the flavored solution. It is not necessary that the poisoned partner be present when the flavored solution is consumed or indeed have had any exposure to the flavored solution. Experiment 3 showed that the unpoisoned partner can exhibit a flavor aversion when there is a temporal gap of as long as 6 hr between consumption of the flavored solution and exposure to the poisoned rat.     

Spatial memory in the rat on a hierarchical maze

Rats were trained and tested on a hierarchical radial maze, which consisted of eight primary alleys radiating from a central platform and three secondary alleys which branched off the end of each primary alley. In four experiments, rats in groups 1, 2, and 3 were tested on maze configurations consisting of one, two, or three secondary alleys, respectively, at the end of each primary alley. In Experiment 1, each group was trained to collect food pellets in the secondary alleys. By the end of training, rats in each group collected all pellets efficiently, with little repetition of entrances into either primary or secondary alleys. In Experiments 2 and 3, tests were carried out which required retention of entrances into secondary alleys, as well as primary alleys. Two trials were run in succession, with selected secondary alleys blocked on trial 1 but open and baited with food on trial 2. Animals in groups 2 and 3 showed very accurate retention of blocked secondary alleys, regardless of variation in pattern and number of alleys blocked. A fourth experiment controlled for the possible use of food cues in Experiments 2 and 3 by rebaiting all secondary alleys between trials 1 and 2. Subjects continued to choose previously blocked alleys on trial 2, thus demonstrating that choice of blocked alleys was based on memory and not on a tendency to approach visual or olfactory food cues. Several findings of these experiments suggest that memories for primary and secondary alley choices are encoded and stored within separate memory systems. Possible coding mechanisms for these systems are discussed with reference to a process of cognitive mapping.     

Sign-tracking in aversive conditioning

Two experiments were conducted to determine if rats tend to avoid contact with a stimulus that signals the occurrence of shock and contact a stimulus that signals the nonoccurrence of shock. The conditioned stimulus was a 60-sec platform presentation, and the unconditioned stimulus was a 2-sec inescapable shock. In each experiment, the emphasis was on two types of Pavlovian pairings: forward pairing in which each platform presentation was followed by shock, and backward pairing in which each platform presentation was preceded by shock and followed by a lengthy shock-free interval. Experiment 1 showed that in comparison with Random and CS-only procedures, the backward procedure produced a significant increase in approach and contact with the platform, but the forward procedure failed to produce a significant decrease in contact with the platform. Experiment 2, in which all groups were roughly equated for baseline levels of platform preference, demonstrated strong effects of both forward and backward conditioning. The experiments provide evidence for an aversive sign-tracking system in which animals' tendencies to withdraw from or approach and contact a platform CS are determined by the Pavlovian contingencies which render it a reliable signal for the occurrence or nonoccurrence of shock.     

The validity of formal and informal personality assessments

Two recent articles by M. Burisch (1984, American Psychologist, 37, 214–227; 1984, Journal of Research in Personality, 18, 81–98) have presented data bearing on the traditional methods by which personality is assessed. Based on a review of selected empirical studies and analyses of new data, Burisch has concluded that (a) single-item global self-ratings generally yield greater coefficients of criterion validity than questionnaire measures of the same traits, and (b) most existing personality questionnaires can be shortened considerably without any consequent loss in validity. These conclusions stand in direct contrast to previous appeals by Epstein and others for the use of extensive aggregate measures of personality derived according to the axioms of psychometric theory. In response to Burisch, we describe measurement artifacts and strategies of test item selection that account for some of his conclusions and we reiterate the need for the application of conventional construct-based questionnaires in the assessment of personality.