Distinct pattern separation related transfer functions in human CA3/dentate and CA1 revealed using high-resolution fMRI and variable mnemonic similarity

Producing and maintaining distinct (orthogonal) neural representations for similar events is critical to avoiding interference in long-term memory. Recently, our laboratory provided the first evidence for separation-like signals in the human CA3/dentate. Here, we extended this by parametrically varying the change in input (similarity) while monitoring CA1 and CA3/dentate for separation and completion-like signals using high-resolution fMRI. In the CA1, activity varied in a graded fashion in response to increases in the change in input. In contrast, the CA3/dentate showed a stepwise transfer function that was highly sensitive to small changes in input.     

Repetition priming of words, pseudowords, and nonwords

In 5 experiments, the authors assessed repetition priming for words, pseudowords, and nonwords using a task that combines an implicit perceptual fluency measure and a recognition memory assessment for each list item. Words and pseudowords generated a consistently strong repetition effect even when there was a failure to recognize the stimulus. In 2 of the experiments, the repetition effect for nonwords was reliably above chance even when there was a failure to recognize the stimulus. The authors propose a parallel distributed processing (PDP) model based on the work of J. McClelland and D. Rumelhart (1985) as a way to understand the mechanisms potentially responsible for the pattern of findings. Although the error-driven nature of learning in the model results in a poor fit to the nonword priming data, this is not endemic to all PDP models. Using a model based on Hebbian learning, the authors instantiate a property that they believe is characteristic of implicit memory--that learning is primarily based on the strengthening of connections between units that become active during the processing of a stimulus. This model provides a far more satisfactory account of the data than does the error-driven model.     

An investigation of appearance motives for tanning: The development and evaluation of the Physical Appearance Reasons For Tanning Scale (PARTS) and its relation to sunbathing and indoor tanning intentions

Motives for UV exposure have been shown to be related to appearance concerns, yet little research has examined specific tan appearance attitudes. Given this lacuna, Study 1 involved the identification of six factors among college female tanners: general attractiveness, media influence, family/friends influence, physical fitness appearance, acne reasons, and skin aging concerns. In Study 2, a separate sample of college female tanners were used to validate a higher order factor model, which demonstrated acceptable fit. Additionally, the factors converged in the expected directions, with the general attractiveness and skin aging concerns being the best correlate of UV exposure and sun-protection intentions. The relevance of these findings to skin cancer prevention is discussed.     

Examining the effects of differential item (functioning and differential) test functioning on selection decisions: when are statistically significant effects practically important?

Item response theory differential test functioning (DTP) methods are often used to address issues in personnel selection, but the results are frequently difficult to interpret because statistically significant findings may have little practical importance. In this article, the authors proposed 2 effect size measures for DTP. One related DTP to mean raw score differences across groups: the other related DTP to the 4/5th rule for adverse impact at successive cut scores. The effects of DTP were examined in the context of personality assessment, professional licensure, and college admissions. Overall, the result indicated that although many items exhibited bias in analyses of the large samples, the net magnitudes of effect on potential selection decisions were nugatory.     

Contrasting Cortical Activity Associated with Category Memory and Recognition Memory

We collected functional neuroimaging data while volunteers performed similar categorization and recognition memory tasks. In the categorization task, volunteers first studied a series of 40 dot patterns that were distortions of a nonstudied prototype dot pattern. After a delay, while fMRI data were collected, they categorized 72 novel dot patterns according to whether or not they belonged to the previously studied category. In the recognition task, volunteers first studied five dot patterns eight times each. After a delay, while fMRI data were collected, they judged whether each of 72 dot patterns had been studied earlier. We found strikingly different patterns of brain activity in visual processing areas for the two tasks. During the categorization task, the familiar stimuli were associated with decreased activity in posterior occipital cortex, whereas during the recognition task, the familiar stimuli were associated with increased activity in this area. The findings indicate that these two types of memory have contrasting effects on early visual processing and reinforce the view that declarative and nondeclarative memory operate independently.     

The rise and fall of Christian science

This paper applies a general theory of why religious movements succeed or fail to explain the meteoric rise of Christian Science, and to explain why the movement began an equally precipitous decline and may soon simply disappear. The analysis is based on quantitative data, on field work and on a variety of historical documents. The fall of Christian Science has many aspects, but particular emphasis is given to inadequate fertility, ineffective socialization, compromises in distinctiveness, a decline in the relative effectiveness of its placebo effects and to the greatly increased occupational opportunities for women.     

Effects of the testing situation on item responding: cause for concern

The effects of faking on personality test scores have been studied previously by comparing (a) experimental groups instructed to fake or answer honestly, (b) subgroups created from a single sample of applicants or nonapplicants by using impression management scores, and (c) job applicants and nonapplicants. In this investigation, the latter 2 methods were used to study the effects of faking on the functioning of the items and scales of the Sixteen Personality Factor Questionnaire. A variety of item response theory methods were used to detect differential item/test functioning, interpreted as evidence of faking. The presence of differential item/test functioning across testing situations suggests that faking adversely affects the construct validity of personality scales and that it is problematic to study faking by comparing groups defined by impression management scores.     

A semiautomatic method for adding behavioral data to videotape records in combination with the Noldus Observer system

The Observer 3.0 (Noldus, 1991) was used as the base for a time-saving fine analysis of animal behavior. A PC controlled a shuttlebox and a shuttlebox control unit. Learning behavior was recorded on videotapes by an S-VHS camcorder with vertical interval time code (VITC), which was used to generate an observational data file (ODF). The observational system was enhanced by automatically recorded status signals from the PC as event markers on the soundtrack of the videotape. These signals were used to subdivide a training session into numbered trials during generation of the ODF. They were later used for a PC-aided fine analysis of behavioral events, such as attention responses (AR) and orienting responses (OR) during shuttlebox learning. In this way, a large number of both automatically inserted PC event markers and manually inserted, key-defined behavioral events were registered and analyzed effectively in a semiautomatic fashion. The system is illustrated with an analysis of shuttlebox avoidance data from gerbils (Meriones unguiculatus).