An integrated theory of the mind

Adaptive control of thought-rational (ACT-R; J. R. Anderson & C. Lebiere, 1998) has evolved into a theory that consists of multiple modules but also explains how these modules are integrated to produce coherent cognition. The perceptual-motor modules, the goal module, and the declarative memory module are presented as examples of specialized systems in ACT-R. These modules are associated with distinct cortical regions. These modules place chunks in buffers where they can be detected by a production system that responds to patterns of information in the buffers. At any point in time, a single production rule is selected to respond to the current pattern. Subsymbolic processes serve to guide the selection of rules to fire as well as the internal operations of some modules. Much of learning involves tuning of these subsymbolic processes. A number of simple and complex empirical examples are described to illustrate how these modules function singly and in concert.     

Effects of ontogeny on performance of rats in a novel object-recognition task

The current experiment investigated ontogenetic forgetting on a novel object-recognition task similar to that of Besheer and Bevins. 18-day-old pups (n = 49) and adult (n = 29) rats were tested at two retention intervals (1 min. or 120 min.). By employing exclusion criteria which demanded minimum amounts of object exploration at training and test, the performance of 18-day-old pups but not that of adults was significantly impaired at 120 min. relative to 1 min. Analysis indicated that the ontogeny of the learning and memory measured in novel object recognition follows a developmental trend similar to that of other forms of learning, with older animals remembering more and thus performing better than younger animals. Unfortunately, given the extreme variability inherent to the task and large N necessary to achieve significance, the use of this task in studies of learning, memory, and development is discouraged.     

Numbers of homosexual parents living with their children

Those contending for the 'normalcy' of homosexuality claim there are 800,000 to 7 million homosexual parents raising between 1 and 9 million children. The 1996 National Household Survey on Drug Abuse, a nationally representative sample of 12,321 ages 18 through 59 yr., reported about 416,000 parents-most of whom were married-living with children under the age of 17 yr. who reported same-sex "vaginal, oral, or anal sex" in the past 12 months. Two random-sample surveys suggested that there are fewer than half a million homosexual parents, and a total sample of 14,000 mothers in Avon suggests even fewer. Thus, it is likely that fewer than 500,000 homosexual parents live with fewer than 750,000 children under 18 yr.     

Neurocognitive mechanisms of cognitive control: the role of prefrontal cortex in action selection, response inhibition, performance monitoring, and reward-based learning

Convergent evidence highlights the differential contributions of various regions of the prefrontal cortex in the service of cognitive control, but little is understood about how the brain determines and communicates the need to recruit cognitive control, and how such signals instigate the implementation of appropriate performance adjustments. Here we review recent progress from cognitive neuroscience in examining some of the main constituent processes of cognitive control as involved in dynamic decision making: goal-directed action selection, response activation and inhibition, performance monitoring, and reward-based learning. Medial frontal cortex is found to be involved in performance monitoring: evaluating outcome vis-a-vis expectancy, and detecting performance errors or conflicting response tendencies. Lateral and orbitofrontal divisions of prefrontal cortex are involved in subsequently implementing appropriate adjustments.     

Context-processing deficits in schizophrenia: diagnostic specificity, 4-week course,and relationships to clinical symptoms

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophia. However, it is not clear whether such deficits are specific to schizophrenia as compared with other psychotic disorders. To address this question, the authors administered a version of the AX Continuous Performance Test designed to assess context processing in a sample of healthy controls, patients with schizophrenia, and patients with other psychotic disorders. Participants were tested at index (when medication naive and experiencing their first contact with psychiatric services) and 4 weeks later, following medication treatment. At index, patients with schizophrenia and the psychotic comparison group demonstrated similar impairments in context processing. However, context-processing deficits improved in the psychotic comparison group at 4 weeks but did not improve in patients with schizophrenia.     

Psychology of the scientist: LXXXV. Research on homosexuality: a response to Schumm (and Herek)

Because social science is "messy," just about any criticism of any work--including our efforts--has validity. But the empiricist principle is more important than a theoretical search for perfection in research. The findings from our 1983-1984 nationwide random survey are superior to earlier efforts and similar enough to those reported by the 1992 nationwide random survey conducted by University of Chicago investigators, the 1994 British effort, and the 1996 NHSDA to suggest all approximate "a similar truth about reported sexuality."     

Cultural meanings of nature: an analysis of contemporary motion pictures

To evaluate current cultural meanings of nature, the authors asked 65 undergraduate students to "list 3 movies in which nature was an important aspect of the film." They also were asked to specify the natural element that stood out to them and describe "how it related to the overall theme of the movie." Two independent groups of raters skilled in interpretive analysis developed thematic meanings from these responses. Following this, in a 2nd study, a different group of participants rated the 18 most frequently mentioned natural elements on thematic scales derived from the initial interpretive analysis. Participants in the 1st study mentioned 33 different movies at least twice and 5 themes that captured the meaning of nature in these films. Correlational results derived from the 2nd study indicated that rating scales reflecting these 5 themes formed 2 distinct groups; the first group described settings in which nature is experienced as adversarial and plays a significant role in dramatic action, and the second group defined settings in which nature is viewed either as a place of refuge or simply as a locale in which ongoing narrative action occurs. The general conclusion reached in both studies concerns the often noted but not always appreciated fact that movies--similar to everyday events and actions--always take place in specific settings and that neither life events nor dramatic narratives can be understood apart from specific settings.     

Inferring the mental processes of other minds

In 4 experiments, the authors examined how several variables influence the quality and quantity of information that people use to make judgments about other people. The results showed that when possible, participants consistently responded appropriately to variables that influenced information that they used to make inferences about other minds. The results also suggested that under circumstances with no opportunity to contrast behavior in different situations, people might not be sensitive to the quality and quantity of information present. The authors interpreted results to mean that under most circumstances, people make inferences in a way that efficiently uses information about the causes of behavior.