Context Specificity of Excitation and Inhibition in Ambiguous Stimuli

Two experiments examined the susceptibility of excitation and inhibition to contextual change when the conditioned stimulus (CS) was ambiguous using an appetitive conditioning paradigm. In Experiment 1, excitation to a CS was lost with a context switch when inhibition had been learned to the CS in a prior feature-negative (FN) discrimination. Control groups that had received either more or less excitatory conditioning in the absence of inhibitory pretraining showed no loss. In Experiment 2 inhibition was lost with a context switch in a group that had received excitatory and then inhibitory conditioning with the CS. No loss was observed in a group that had not received excitatory pretraining. The results suggest that contexts are especially likely to control performance to ambiguous CSs when they can modulate the second of two learned associations. Results are discussed in terms of their implications for occasion setting and modern conditioning theory.     

General Learned Irrelevance and Its Prevention

Random presentation of a tone and an electric shock to rats interfered with subsequent acquisition of a light–shock association. This interference, or “general learned irrelevance” phenomenon, however, could be prevented by prior learning of a positive relationship between the tone and the shock or that between a noise and the shock. These results strongly support the ideas that animals learn irrelevant stimulus relationships and that prior experience of stimulus relevance prevents learning irrelevance. The similarity of this observed prevention effect to an immunization effect on learned helplessness phenomena is discussed.     

Why do Alzheimer patients have difficulty with pronouns? Working memory, semantics, and reference in comprehension and production in Alzheimer's disease

Three experiments investigated the extent to which semantic and working-memory deficits contribute to Alzheimer patients' impairments in producing and comprehending referring expressions. In Experiment 1, the spontaneous speech of 11 patients with Alzheimer's disease (AD) contained a greater ratio of pronouns to full noun phrases than did the spontaneous speech produced by 9 healthy controls. Experiments 2 and 3 used a cross-modal naming methodology to compare reference comprehension in another group of 10 patients and 10 age-matched controls. In Experiment 2, patients were less sensitive than healthy controls to the grammatical information necessary for processing pronouns. In Experiment 3, patients were better able to remember referent information in short paragraphs when reference was maintained with full noun phrases rather than pronouns, but healthy controls showed the reverse pattern. Performance in all three experiments was linked to working memory performance but not to word finding difficulty. We discuss these findings in terms of a theory of reference processing, the Informational Load Hypothesis, which views referential impairments in AD as the consequence of normal discourse processing in the context of a working memory impairment.     

A Cross-Cultural Study of Response Biases in Personality Measures

The purposes of this study were to (a) compare the response bias tendencies of U.S. and Philippine college students and men and women in each culture when responding to personality measures, (b) examine the comparability of different measures of the same response biases, (c) examine the stability or consistency of response biases across instruments, (d) examine the extent to which controlling for response biases affects cultural mean comparisons in personality variables, and (e) test hypothesized personality correlates of response biases. The results did not support the presence of large cross-cultural or gender differences in response biases. Moderate to high agreement was found between different indexes of the same biases. Participants' response bias tendencies were moderately stable across instruments. Controlling for response biases led to trivial changes in effect sizes; in most cases, conclusions about cultural differences in personality constructs did not change. Most hypotheses relating personality variables to response biases were not supported.     

Sex differences in functional cerebral asymmetries in a repeated measures design

The aim of the present study was to analyze whether task repetitions which are an inevitable part of repeated measures designs might induce performance alterations specific for gender and hemisphere. Male and female subjects conducted twice a lexical decision, a polygon recognition, and a face discrimination task as a visual half field paradigm with the two experimental sessions repeated by 2 weeks. The results show that only in female subjects can a session effect for the lexical decision and the polygon recognition task be demonstrated which is hemisphere specific. Thus, repeated measures designs seem to have a gender- and hemisphere-specific effects of their own which could confound with other variables under study.     

Dopamine and the origins of human intelligence

A general theory is proposed that attributes the origins of human intelligence to an expansion of dopaminergic systems in human cognition. Dopamine is postulated to be the key neurotransmitter regulating six predominantly left-hemispheric cognitive skills critical to human language and thought: motor planning, working memory, cognitive flexibility, abstract reasoning, temporal analysis/sequencing, and generativity. A dopaminergic expansion during early hominid evolution could have enabled successful chase-hunting in the savannas of sub-Saharan Africa, given the critical role of dopamine in counteracting hyperthermia during endurance activity. In turn, changes in physical activity and diet may have further increased cortical dopamine levels by augmenting tyrosine and its conversion to dopamine in the central nervous system (CNS). By means of the regulatory action of dopamine and other substances, the physiological and dietary changes may have contributed to the vertical elongation of the body, increased brain size, and increased cortical convolutedness that occurred during human evolution. Finally, emphasizing the role of dopamine in human intelligence may offer a new perspective on the advanced cognitive reasoning skills in nonprimate lineages such as cetaceans and avians, whose cortical anatomy differs radically from that of primates.     

Controversies about CP: a comparison of language acquisition and language impairments in Broca's aphasia

In both language acquisition research and the study of language impairments in Broca's aphasia there is an ongoing debate whether or not phrase-structure representations contain the Complementizer Phrase (CP) layer. To shed some light on this debate, I will provide data on German child language and on German agrammatic Broca's aphasia. Analyses of subordinate clauses, wh-questions, and verb placement indicate that early child grammars do not generate the CP layer yet, whereas the ability to project the CP layer is retained in agrammatism.     

Maternal Personality and Distress as Predictors of Child Neglect

Previous studies suggest that maternal personality problems predict child neglect. However, these studies have not distinguished between the common and unique contributions of various maternal personality dimensions, nor have they compared the contribution of maternal personality with maternal emotional distress. The current study addresses these issues using data collected by James Gaudin and distributed by the National Data Archive on Child Abuse and Neglect at Cornell University. Information was extracted on 94 neglectful and 101 comparison mothers. Logistic regression analyses revealed that a composite score reflecting maternal empathic capacity inversely predicted child neglect, whereas maternal depressive symptoms and loneliness did not. Results are discussed in terms of the importance of distinguishing between common and unique contributions of maternal personality dimensions to clinical and social outcomes and in terms of the relative contribution of maternal personality and emotional distress to child neglect.     

Understanding Disorders in Agrammatic Patients: Capacity or Structural Deficits?

Several hypotheses have been advanced in recent years to understand difficulties in agrammatic patients. Some of them are of a structural kind, as the deficiency is said to lie in some of the linguistic system components. Others are of a functional type, as it is stated that the problem of these patients lies in the loss of processing capacity.Using the existence of a syntactic type of structure in Spanish, that active sentences do not follow the canonical S-V-O order, we will try to prove in this article whether agrammatic patients' problems are due to memory span loss or to one of the syntactic process mechanisms. To this end, the performances of three groups of patients are contrasted. Agrammatic, anomic, and normal Spanish speakers are given several tasks of sentence–picture matching and tests of memory span.Results show that agrammatic patients have specific difficulties processing certain syntactical structures; however, their memory deficiencies are not more pronounced than in other patients. It can be concluded, therefore, that the deficiencies of agrammatic patients are of a structural character rather than due to memory span loss.     

Right Hemisphere Activation during Indirect Semantic Priming: Evidence from Event-Related Potentials

Healthy subjects performed a lexical decision task in a semantic priming paradigm while event-related potentials (ERPs) were recorded from 64 channels. Semantic distance between prime and target was varied by including directly, indirectly, and nonrelated word pairs. At centro-parietal electrodes an N400 to nonrelated pairs was elicited bilaterally which was sensitive only to direct, but not to indirect semantic priming. These N400 priming effects were mirrored by the RT data. At inferior fronto-temporal sites directly related words showed ERP priming effects over both hemispheres. However, indirectly related words only elicited ERP priming effects over the right hemisphere. These results support the hypothesis that the right hemisphere semantic system is involved in processing of remote semantic information.