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.     

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.     

Visual information and the control of reaching in children: a comparison between children with and without developmental coordination disorder

Three experiments were performed on reach and grasp in 9- to 10-year-old children (8 controls and 8 with developmental coordination disorder [DCD]). In normal reaching, children in the DCD group were less responsive to the accuracy demands of the task in controlling the transport component of prehension and spent less time in the deceleration phase of hand transport. When vision was removed as movement began, children in the control group spent more time decelerating and reached peak aperture earlier. Children in the DCD group did not do that, although, like the control group, they did increase grip aperture in the dark. When depth cues were reduced and only the target or only the target and hand were visible, children in the control group used target information to maintain the same grip aperture in all conditions, but DCD children behaved as if the target was not visible. Throughout the studies, the control group of 9- to 10-year-olds did not produce adult-like adaptations to reduced vision, suggesting that they had not yet attained adult-like integration of sensory input. Compared with control children, children with DCD did not exhibit increased dependence on vision but showed less recognition of accuracy demands, less adaptation to the removal of vision, and less use of minimal visual information when it was available.     

A hybrid model of categorization

Category learning is often modeled as either an exemplar-based or a rule-based process. This paper shows that both strategies can be combined in a cognitive architecture that was developed to model other task domains. Variations on the exemplar-based random walk (EBRW) model of Nosofsky and Palmeri (1997b) and the rule-plus-exception (RULEX) rule-based model of Nosofsky, Palmeri, and McKinley (1994) were implemented in the ACT-R cognitive architecture. The architecture allows the two strategies to be mixed to produce classification behavior. The combined system reproduces latency, learning, and generalization data from three category-learning experiments--Nosofsky and Palmeri (1997b), Nosofsky et al., and Erickson and Kruschke (1998). It is concluded that EBRW and ACT-R have different but equivalent means of incorporating similarity and practice. In addition, ACT-R brings a theory of strategy selection that enables the exemplar and the rule-based strategies to be mixed.     

Higher-education administrators: when the future does not make a difference

The relationships between administrative actions and their long-term consequences were investigated in 14 people beginning training to become high-level college and university administrators, 19 people who had just finished that training, and 44 provosts (chief academic officers) at colleges and universities in the northeastern United States. The experienced administrators (those who had completed the training plus the provosts) were significantly more likely than the trainees to mention long-term consequences when describing their past and possible future administrative actions. However, in hypothetical choice situations, the experienced administrators were also significantly more likely than the trainees to choose smaller amounts of funds available immediately for their units versus larger amounts of promised future funds. With experience, administrators may both become more aware of their actions' long-term consequences and learn that they are unlikely to receive promised future funds. The contingencies in effect for higher-education administrators may lead them to make choices that do not result in their institutions meeting the highest standards.