Response latencies in human matching-to-sample

Optimum characterization of individual information-processing skills requires isolation of assessable components. In matching-to-sample, three elementary processes might be separated if a proposed model of serial, selfterminating search were supported: registration of the stimulus in short-term memory, comparison of the two registered stimuli, and execution of the identifying response. Support for the model was obtained when response latencies were examined as a function of left-to-right position of the target stimulus in a display, but quantitative estimates of components could not be made because of interactions between tasks and the linearity of the scanning process. A second experiment, which varied the number of comparison stimuli, yielded highly linear functions whose slopes and intercepts violated certain aspects of the model. Data on eye movements obtained in a third experiment again supported the basic model but indicated that median response latencies represent a confounding of optimal and suboptimal performances.     

Genetic and Environmental Effects on Openness to Experience, Agreeableness, and Conscientiousness: An Adoption/Twin Study

ABSTRACT Previous research has indicated that extraversion and neuroticism are substantially affected both by genotype and environment. This study assesses genetic and environmental influences on the other three components of the five-factor model of personality: Openness to Experience, Agreeableness, and Conscientiousness. An abbreviated version of the NEO Personality Inventory (NEO-PI) was administered to 82 pairs of identical twins and 171 pairs of fraternal twins reared apart and 132 pairs of identical twins and 167 pairs of fraternal twins reared together. Estimates of genetic and environmental effects for Openness and Conscientiousness were similar to those found in other studies of personality: Genetic influence was substantial and there was little evidence of shared rearing environment. Results for Agreeableness were different: Genetic influence accounted for only 12% of the variance and shared rearing environment accounted for 21% of the variance. Few significant gender or age differences for genetic and environmental parameters were found in model-fitting analyses.     

Grading the ‘cultural literacy’ project

The essay examines the argument advanced by E.D. Hirsch, Jr., for instituting ‘cultural literacy’ as a fundamental priority of schools. A number of confusions and equivocations in Hirsch's reasoning are identified, and the propensity of his project to indoctrinate is exposed. Among the features of Hirsch's argument shown to be troubling are his shifting construal of ‘language’, his inconsistency about the requirements of cultural literacy, and his uncritical relation to traditional images of the American past and present. The upshot is to raise the question why Hirsch's project has elicited wide support and praise.     

Glucose and physostigmine effects on morphine- and amphetamine-induced increases in locomotor activity in mice

Recent findings indicate that glucose antagonizes several behavioral effects of cholinergic antagonists and augments those of cholinergic agonists. For example, scopolamine elicits increased locomotor activity, an action which is attenuated by glucose and by combined treatment with glucose and physostigmine at doses which are individually without effect. Opiate and catecholamine agonists, such as morphine and amphetamine, also elicit hyperactivity. The present study examined interactions of glucose and physostigmine with morphine- and amphetamine-induced hyperactivity. Mice received saline, morphine (10 mg/kg), or amphetamine (1 mg/kg) 50 min prior to testing, followed by saline, physostigmine (0.01, 0.05, 0.1, or 0.2 mg/kg), or glucose (10, 50, 100, or 500 mg/kg) administered 20 min prior to activity testing in an open field. Physostigmine significantly attenuated both morphine- and amphetamine-induced increases in activity, but higher doses were required to attenuate the effects of amphetamine. Like physostigmine, glucose significantly attenuated morphine-induced activity levels, but unlike physostigmine, glucose did not attenuate amphetamine-induced activity. Thus, the behavioral effects of morphine were more susceptible to modification by physostigmine and glucose than were the effects of amphetamine. The attenuation of morphine-induced hyperactivity demonstrates a similarity between glucose and cholinergic agonists, and also indicates that glucose may inhibit, directly or indirectly, opiate functions. More generally, these findings add to the evidence that circulating glucose levels selectively influence a growing list of behavioral and neurobiological functions.     

What is the pronunciation for -ough and the spelling for /u/? A database for computing feedforward and feedback consistency in English

Recent studies suggest that performance attendant on visual word perception is affected not only by feedforward inconsistency (i.e., multiple ways to pronounce a spelling) but also by feedback inconsistency (i.e., multiple ways to spell a pronunciation). In the present study, we provide a statistical analysis of these types of inconsistency for all monosyllabic English words. This database can be used as a tool for controlling, selecting, and constructing stimulus materials for psycholinguistic and neuropsychological research. Such large-scale statistical analyses are necessary devices for developing metrics of inconsistency, for generating hypotheses for psycholinguistic experiments, and for building models of word perception, speech perception, and spelling.     

Informal Caregiving to Persons with AIDS in the United States: Caregiver Burden Among Central Cities Residents Eighteen to Forty-Nine Years Old

Characteristics and caregiving experiences of friends and family members caring for people with AIDS (PWAs) were examined. Based on a probability sample of informal AIDS caregivers ages 18–49 living in central cities of the United States (n = 260), analyses were conducted to (a) identify the sociodemographic characteristics of young central city caregivers; and (b) examine the effects of caregiver characteristics (relationship to PWA, gender, race/ethnicity, income, sexual orientation, HIV status, perceived susceptibility), and level of objective caregiving demands, on subjective caregiver burden. Results indicate that the largest group of caregivers in this age category are male friends of the PWA—a group not typically found among caregivers to persons with other types of illnesses. In general, gay or bisexual caregivers, caregivers who have traditional family ties to the PWA, men relative to women, and lower income caregivers, report the greatest burden. While level of caregiving demands represents the most influential predictor of caregiver burden, white and male caregivers experience greater burden, independent of level of involvement and other caregiver characteristics. Receiving instrumental support with caregiving buffers the impact of high objective demands on subjective burden.     

Hippocampal synaptic plasticity during instrumental learning

present research examined the role of hippocampal NMDA-dependent synaptic potentiation on appetitive instrumental conditioning under a continuous reinforcement schedule. In the first experiment, low (.025 mg.kg) or moderate (.05 mg/kg) dosages of the NMDA receptor antagonist, MK801, failed to increase the number of training days required to reach acquisition criterion; number of training days required to reach criterion for extinction were also unaffected. In the second experiment, a higher dosage (.10 mg/kg) of MK801 or induction of long-term potentiation failed to alter the number of responses occurring during acquisition. These data suggest that hippocampal synaptic potentiation does not play a prominent role in instrumental learning with simple contingency conditions. It is suggested that hippocampal LTP reflects a perceptual process that contributes differentially to spatial cognition, classical and instrumental conditioning.     

Developing local lifelong guidance strategies

The background, rationale, methodology and outcomes of a project on developing local lifelong guidance strategies in four areas are outlined. The main components of the strategies developed in the four areas are analysed, and a number of issues relating to the process of strategy development are addressed. Much of the lack of coherence at local level stems from lack of coherence at national policy level: implications for national policy are examined. Finally, implications for parallel work in other localities are explored.     

Hippocampal synaptic plasticity during instrumental learning

present research examined the role of hippocampal NMDA-dependent synaptic potentiation on appetitive instrumental conditioning under a continuous reinforcement schedule. In the first experiment, low (.025 mg.kg) or moderate (.05 mg/kg) dosages of the NMDA receptor antagonist, MK801, failed to increase the number of training days required to reach acquisition criterion; number of training days required to reach criterion for extinction were also unaffected. In the second experiment, a higher dosage (.10 mg/kg) of MK801 or induction of long-term potentiation failed to alter the number of responses occurring during acquisition. These data suggest that hippocampal synaptic potentiation does not play a prominent role in instrumental learning with simple contingency conditions. It is suggested that hippocampal LTP reflects a perceptual process that contributes differentially to spatial cognition, classical and instrumental conditioning.