Hippocampal and neocortical contributions to memory: advances in the complementary learning systems framework

The complementary learning systems framework provides a simple set of principles, derived from converging biological, psychological and computational constraints, for understanding the differential contributions of the neocortex and hippocampus to learning and memory. The central principles are that the neocortex has a low learning rate and uses overlapping distributed representations to extract the general statistical structure of the environment, whereas the hippocampus learns rapidly using separated representations to encode the details of specific events while minimizing interference. In recent years, we have instantiated these principles in working computational models, and have used these models to address human and animal learning and memory findings, across a wide range of domains and paradigms. Here, we review a few representative applications of our models, focusing on two domains: recognition memory and animal learning in the fear-conditioning paradigm. In both domains, the models have generated novel predictions that have been tested and confirmed.     

Metaphor and Persuasive Communication: A Multifunctional Approach

Metaphors are pervasive in both mass communication and interpersonal exchanges and can play an important role in persuasion. Metaphor serves multiple functions in persuasive communication, and the effect of metaphor on persuasion is potentially mediated by multiple psychological process mechanisms. Nevertheless, we propose that past and future research in this area can be organized or grouped into three simple categories. First, metaphorical statements can activate information that is directly applied to the communication topic and thereby influence attitudes toward the communication topic. Second, metaphorical language may influence impressions of the communication source and thereby impact attitudes toward the communication topic. Third, metaphors may affect attitudes toward the communication topic by influencing the direction or amount of elaboration that takes place when recipients process literal statements contained in the communication. A review of past research is organized into these three categories, and proposals for future research in each category are introduced. It is concluded that future research within each of these domains should focus on two related questions: under what conditions does metaphor elicit a given psychological process in the receiver (e.g., attribute mapping, valence transfer), and under what conditions will a given process result in an increase versus decrease in persuasion?     

Agonistic interpersonal striving: social-cognitive mechanism of cardiovascular risk in youth?

The social competence model (SCM) of cardiovascular disease (CVD) risk identifies combinations of goal-oriented strivings, expressive behaviors, and social skill deficits that contribute to persisting interpersonal difficulties and chronic health-damaging stress in youth. SCM hypotheses were tested on 187 Black and White adolescents who completed the Social Competence Interview (SCI) and later underwent ambulatory blood pressure (ABP) monitoring. Cluster analyses of stress narratives assessed via SCI identified 3 predicted stress profiles: agonistic (interpersonally focused), transcendent (self-development focused), and avoidant. Group comparisons using social, hemodynamic, and ABP data supported the SCM hypothesis that youths who exhibit the agonistic striving profile display diminished social competence, negative social impact, and heightened cardiovascular responding during a stress interview, and elevated ABP during normal social interactions, thus suggesting higher risk of CVD.     

Psycholinguistic correlations of academic achievement

This research investigated the relationship of the ITPA subtests to measures of academic performance (i.e., the California Achievement Test). Subjects were 137 9-year old children similar to those used in the standardization sample of the 1968 revision of the ITPA. Two kinds of data analyses were undertaken-1. correlation coefficients among the variables were derived, and 2. the subjects were divided into low, average, and high groups based on their CAT performance, and analyses of covariance were run to determine the significance of ITPA differences. The results failed to support the hypothesis that psycholinguistic abilities, except those which contribute to the Grammatic Closure subtest, are related to academic proficiency.     

The effect of change in US quality on the blocking effect

If one CS is paired with a US and then that CS together with a “redundant” stimulus is paired with the US, conditioning of that “redundant” stimulus is attenuated or blocked. The present experiment explores the effect upon this blocking of changing the quality of the US coincident with the introduction of the redundant stimulus. Changing US quality disrupted blocking only when the US potency was also increased. Quality changes in which the redundant stimulus was correlated with a lower potency US only increased blocking. These results are taken as supporting the conditioning model of Rescorla and Wagner but inconsistent with a casual informational model of conditioning.