Lexical decision and aphasia: Evidence for semantic processing

Wernicke's and Broca's-Conduction aphasics and a Global aphasic were presented with a lexical-decision task in which English words and pronounceable nonwords were preceded by semantically related, unrelated, or nonword primes. The patients were also given a simple semantic-judgment task using the word pairs from the lexical-decision task. Wernicke's aphasics performed similar to normals and Broca's-Conduction aphasics showing significantly shorter latencies in making real-word identifications when preceded by a semantically related word. In addition, both superordinate and coordinate associates showed semantic-priming effects. Performance on the semantic-judgment task showed significantly more impairment in the aphasic group than in the normal controls. These results suggest that aphasics with even severe language impairments retain stored semantic information that may be automatically activated, yet is inaccessible to conscious semantic decision during metalinguistic tasks.     

Preservation of orthographic knowledge in aphasia

A simple untimed lexical decision task was designed to test implicit letter recognition in aphasic patients. Half of the nonwords used in this task were orthographically regular pronounceable pseudowords, and half were orthographically irregular unpronounceable letter strings. Twenty-five randomly chosen aphasic patients with mild to severe degrees of aphasia participated in the study. Although only six of the patients performed the lexical decision task successfully, all 25 demonstrated the ability to distinguish orthographically regular from irregular letter strings and, by implication, the ability to recognize and make use of the identities of written letters.     

Reversal learning in young children as a function of number of choice-alternatives

Discrimination learning and reversal problems were given to 128 children aged two and three years in which there were either two, three, six, or nine choice-alternatives per problem. The position of the correct object (either a toy car on the original problem and a ball on the reversal problem or vice versa) was varied randomly among all the possible positions, all other positions being occupied by duplicates of the incorrect object. It was found that two-choice reversal problems were much more difficult than all others. There was also a direct and monotonic relationship between ease of solution and number of choices present during reversal learning. Additional analysis inlicated that position response biases were probably responsible for this effect.     

Psychological effects of complex environments during the life span: A review and theory

This paper reviews evidence supporting a theory about the psychological effects of complex environments suggested by research on the causal relationships between occupational conditions and psychological functioning. The review indicates that environmental complexity leads to effective cognitive functioning across all stages of the life span. This effect has been found in both sexes, in several nations, and in species other than man. Although the evidence is not as extensive, environmental complexity also appears to lead to a self-directed rather than conformist orientation.     

Recognition memory and intelligence

The assumption that individual differences in recognition memory are associated with individual differences in intelligence was explored by administering intelligence tests and tests of immediate visual recognition memory to a sample of 52 5-year-old children expected to vary widely from one another in intelligence. Each child was given the Peabody Picture Vocabulary Test (Form L) and two tests of immediate recognition memory: one test for 27 abstract patterns and one test for 27 unfamiliar cartoon faces. The mean PPVT-IQ for the sample was in the average range at 98.1. Interindividual variability in IQ proved to be high as reflected in the group SD of 22.6, with scores ranging from 40 to 136. The recognition tasks proved to be of moderate difficulty. Individual differences in memory for patterns were highly related to memory for faces (r = .76), indicating that the overall recognition test was reliable. The most important result of the present study was the strong association between recognition memory performance and PPVT-IQ of .70. The relation between recognition memory and IQ could not be accounted for by the inclusion of a few very low IQ children, since the association remained high at .61 when children with IQs below 75 were omitted from analysis. In short, the present results indicate that immediate recognition memory is highly associated with intelligence.     

A laboratory test of the constant risk hypothesis

It has been repeatedly suggested that subjects aim at maintaining a constant error probability in many variants of self-paced performance and that they adjust their behaviour so as to keep their risks relatively constant. This constant risk hypothesis is investigated in a simple computer-controlled addition task it which subjects manipulated exercise difficulty as a function of their own calculation proficiency and the allotted solution time. Error probability proved to be unrelated to level of skill and to amount of allotted computation time, but to depend onuncertainty with respect to exercise difficulty.     

Choice reaction times in children: Error and post-error responses,and the repetition effect

Analysis of the frequency and nature of error and post-error responses in the serial choice reaction times (RTs) of children between 5 and 12 years essentially replicate findings in adults. Errors are few and fast, tend to be made on fingers closely related to the correct responding finger, and are followed by a marked slowing in response rate. This pattern of results is interpreted in terms of a strategy to optimize performance with respect to instructions emphasizing both speed and accuracy. Importantly, this may be seen to reflect the activity, even in the youngest of children, of a finely-tuned feedback mechanism for error detection. Only the extent of immediate post-error slowing shows a decline with age, and is referred to improvements in response programming. Repetition RT is much faster than alternation RT (the “Repetition Effect”) and improves much less rapidly with age. Reduction of the Repetition Effect with age is consistent with theories of RT in which signals are categorized by retrospective search in short-term memory. The girls' advantage in gross RT is found to be confined to alternation RT only. The particular contribution of alternation RT both to the development of, and sex difference in, gross RT is related to the greater response organization involved in rapidly switching between fingers and hands.     

Laterality differences for word identification in bilinguals

Twenty-three Spanish-English bilinguals were tachistoscopically presented with four-letter common nouns. They viewed 20 word pairs, first in their native language, then in the other, for 40 msec under simultaneous bilateral exposure. This paradigm has previously shown a strong right visual field and therefore left hemisphere superiority for words in a single language. The results show a word identification advantage in the right visual field. This indicates a left hemisphere advantage for processing of both languages, regardless of which was learned first. There are nevertheless wide individual differences in the number of bilinguals showing the expected asymmetry, as compared with monolinguals. There may be a trend, therefore, for less unilaterality of language function in bilinguals, although both languages are seen as being equally lateralized.     

Hemispheric emotional asymmetry in a dichotic listening task.

In a dichotic listening experiment white noise was played to one ear and either music or poetry to the other ear. Subjects rated the stimuli on each of three dimensions. The results showed that both music poetry were judged as more pleasant when heard at the left than the right ear. In addition the music, but not the poetry, was perceived as more soothing at the left ear. The findings are discussed in relation to other indications in the literature that left and right cerebral hemispheres differ in their emotional make-up.     

Integrative Complexity of 41 U.S. Presidents

Although U.S. presidents are one of the most studied groups of political figures and integrative complexity is one of the most widely used constructs in political psychology, no study to date has fully examined the integrative complexity of all U.S. presidents. The present study helps fill in that gap by scoring 41 U.S. presidents' first four State of the Union speeches for integrative complexity and then comparing these scores with a large range of available situational and personality variables. Results suggest a tendency for presidents' integrative complexity to be higher at the beginning of their first term and drop at the end. This pattern was pronounced for presidents who eventually won reelection to a second term and was markedly different for presidents who tried to gain reelection but lost. Additional analyses suggested that presidents' overall integrative complexity scores were in part accounted for by chronic differences between presidents' complexity levels. Further analyses revealed that this overall integrative complexity score was positively correlated to a set of interpersonal traits (friendliness, affiliation motive, extraversion, and wittiness) and negatively correlated with inflexibility. Discussion centers upon the causes and consequences of presidential complexity.