Faster forgetting contributes to impaired spatial memory in the PDAPP mouse: Deficit in memory retrieval associated with increased sensitivity to interference?

Two experiments were conducted to investigate the possibility of faster forgetting by PDAPP mice (a well-established model of Alzheimer's disease as reported by Games and colleagues in an earlier paper). Experiment 1, using mice aged 13-16 mo, confirmed the presence of a deficit in a spatial reference memory task in the water maze by hemizygous PDAPP mice relative to littermate controls. However, after overtraining to a criterion of equivalent navigational performance, a series of memory retention tests revealed faster forgetting in the PDAPP group. Very limited retraining was sufficient to reinstate good memory in both groups, indicating that their faster forgetting may be due to retrieval failure rather than trace decay. In Experiment 2, 6-mo-old PDAPP and controls were required to learn each of a series of spatial locations to criterion with their memory assessed 10 min after learning each location. No memory deficit was apparent in the PDAPP mice initially, but a deficit built up through the series of locations suggestive of increased sensitivity to interference. Faster forgetting and increased interference may each reflect a difficulty in accessing memory traces. This interpretation of one aspect of the cognitive deficit in human mutant APP mice has parallels to deficits observed in patients with Alzheimer's disease, further supporting the validity of transgenic models of the disease.     

Biases towards internal features in infants' reasoning about objects

This paper reports the results of two sets of studies demonstrating 14-month-olds' tendency to associate an object's behavior with internal, rather than external features. In Experiment 1 infants were familiarized to two animated cats that each exhibited a different style of self-generated motion. Infants then saw a novel individual that had an internal feature (stomach color) similar to one cat, but an external feature (hat color) similar to the other. Infants looked reliably longer when the individual's motion was congruent with the hat than when it was congruent with the stomach. Using a converging method involving object choice, Experiment 2 found that infants prioritized the internal feature over the external feature only when the object's behavior was self-generated. In the absence of self-generated behaviors, however, infants did not show a preference towards the internal feature.     

Introducing ELW: Facilitating a Smooth Transition

Abstract : The author discusses how a combination of trust and teaching helped make the transition from the LBW to ELW more of a pleasurable transition than anticipated. While several characteristics of ELW have proved troublesome, the pattern of trust and teaching built over eleven years, along with flexibility, made it work.     

A test of the factor structure equivalence of the 50-item IPIP Five-factor model measure across gender and ethnic groups

Personality is frequently assessed in research and applied settings, in part due to evidence that scores on measures of the Five-factor model (FFM) of personality show predictive validity for a variety of outcomes. Although researchers are increasingly using the International Personality Item Pool (IPIP; Goldberg, 1999; International Personality Item Pool, 2007b) FFM measures, investigations of the psychometric properties of these measures are unfortunately sparse. The purpose of this study was to examine the factor structure equivalence of the 50-item IPIP FFM measure across gender and ethnic groups (i.e., Whites, Latinos, Asian Americans) using multigroup confirmatory factor analysis. Results from a sample of 1,727 college students generally support the invariance of the factor structure across groups, although there was some evidence of differences across gender and ethnic groups for model parameters. We discuss these findings and their implications.     

The Content of Behavior Therapy for Depression Demonstrates Few Associations With Treatment Outcome Among Low-Income, Medically Ill Older Adults

We reported previously the results of a randomized controlled trial of a home-based behavioral treatment for dysthymia or minor depression that emphasized problem solving and activity scheduling among low-income, medically ill older adults. This report focuses on the content of treatment sessions as predictors of depressive symptoms, social activity, and physical activity outcomes among 64 participants who completed 2 or more sessions and evaluations at 6 and 12 months after the baseline evaluation. Worksheets from the treatment sessions were coded for focus on 4 types of problems (functional, social, health/physical, emotional); the number of activities planned was counted. More activity scheduling was associated with increased physical activity at the 12-month evaluation relative to baseline. The limited findings suggest either that the study methodology did not reveal extant associations between treatment variables and outcomes or that the session content variables tested in this study are not the active ingredients of treatment.