Spatial learning and memory is preserved in rats after early development in a microgravity environment

This study evaluated the cognitive mapping abilities of rats that spent part of their early development in a microgravity environment. Litters of male and female Sprague-Dawley rat pups were launched into space aboard the National Aeronautics and Space Administration space shuttle Columbia on postnatal day 8 or 14 and remained in space for 16 days. These animals were designated as FLT groups. Two age-matched control groups remained on Earth: those in standard vivarium housing (VIV) and those in housing identical to that aboard the shuttle (AGC). On return to Earth, animals were tested in three different tasks that measure spatial learning ability, the Morris water maze (MWM), and a modified version of the radial arm maze (RAM). Animals were also tested in an open field apparatus to measure general activity and exploratory activity. Performance and search strategies were evaluated in each of these tasks using an automated tracking system. Despite the dramatic differences in early experience, there were remarkably few differences between the FLT groups and their Earth-bound controls in these tasks. FLT animals learned the MWM and RAM as quickly as did controls. Evaluation of search patterns suggested subtle differences in patterns of exploration and in the strategies used to solve the tasks during the first few days of testing, but these differences normalized rapidly. Together, these data suggest that development in an environment without gravity has minimal long-term impact on spatial learning and memory abilities. Any differences due to development in microgravity are quickly reversed after return to earth normal gravity.     

Are Nativists a Different Kind of Democrat? Democratic Values and “Outsiders” in Japan

This paper combines three elements: a discussion of democratic values and the status of outsiders in Japanese political culture, the development of new measures to examine sensitive issues of nativism and foreigner perception in Japan, and an empirical exploration of the relationship between democratic values and antipathy toward outsiders. Two forms of democratic orientation were investigated in a sample of about 1,000 university students in Japan: a defensive version, which adheres to the formalistic requirements of democracy but is exclusionary and illiberal, and a universalist version that is liberal and tolerant. A defensive orientation is associated with greater chauvinism, a greater sense of threat emanating from foreigners, and a heightened anxiety about economic competition. A universalist orientation is associated with low perceived threat and low chauvinism, a lack of fear of economic competition, and a positive view of the cultural contributions of outsiders. Nativism may indeed be compatible with democratic values, but only with the defensive, exclusionary form. In short, the defensive form is democracy for xenophobes. Such an orientation is not unique to Japan, but is likely to be found in developing democracies as well as in advanced democracies that feel threatened.     

EVENT-RELATED BRAIN POTENTIALS, EYE MOVEMENTS, AND READING

Abstract— This article compares studies that use event-related brain potential (ERP) and eye movement data to examine changes in reading behavior when a text is read twice. Although the types of information provided by these methodologies are different, both indicate that rereading a text facilitates many aspects of processing. ERPs provide a method for measuring comprehension and memory processes separately, while eye movements provide a continuous record of performance and allow changes in reading behavior to be localized to specific words. The results from these studies are compatible. However, converging evidence is not always found when different paradigms are contrasted, and diverging results can provide important information. To facilitate comparison across experiments, we suggest using a common set of materials for both paradigms. We conclude that comparing the results of research based on more than one paradigm provides a more complete understanding of the processes involved in reading.     

Spelling-sound regularity effects on eye fixations in reading

An interaction of word frequency and word regularity has typically been observed in naming and lexical decision experiments in which, in addition to an overall effect of word frequency, responses to low-frequency exception words are slower than those to low-frequency regular words, while no such difference occurs with high-frequency words. The only eye movement study to examine this effect in reading (Inhoff & Topolski, 1994) reported only transient effects of regularity. In the present experiment, we examined the frequency x regularity interaction using different stimuli than those of Inhoff and Topolski and also varied the parafoveal preview of the target word prior to fixation. When the preview was valid, the frequency x regularity interaction appeared. However, with an invalid preview, the effect of regularity disappeared. The results suggest that the activation of phonological codes is a very early component of reading.     

The prediction of averages

Criterion measures are frequently obtained by averaging ratings, but the number and kind of ratings available may differ from individual to individual. This raises issues as to the appropriateness of any single regression equation, about the relation of variance about regression to number and kind of criterion observations, and about the preferred estimate of regression parameters. It is shown that if criterion ratings all have the same true score the regression equation for predicting the average is independent of the number and kind of criterion scores averaged.Two cases are distinguished, one where criterion measures are assumed to have the same true score, and the other where criterion measures have the same magnitude of error of measurement as well. It is further shown that the variance about regression is a function of the number and kind of criterion ratings averaged, generally decreasing as the number of measures averaged increases. Maximum likelihood estimates for the regression parameters are derived for the two cases, assuming a joint normal distribution for predictors and criterion average within each subpopulation of persons for whom the same type of criterion average is available.     

Letter-by-letter acquired dyslexia is due to the serial encoding of letters

Letter-by-letter acquired dyslexia (pure alexia) is assumed to be related to the serial encoding of letters, but the evidence for this assumption is somewhat indirect. Here, we demonstrate that the deficit is indeed due to serial encoding by comparing the performance of a letter-by-letter dyslexic reader with the performance of normal readers who were forced to read letter by letter; the data patterns are remarkably similar.     

The tripartite model of anxiety and depression: symptom structure in depressive and hypertensive patient groups

The structure of self-reported symptoms representative of the tripartite model was examined using data drawn from the Medical Outcomes Study (Tarlov et al., 1989). Participants were persons who had been diagnosed 48 months previously as suffering from either depression (N = 315) or hypertension (N = 403). Results of confirmatory factor analyses were broadly consistent with the tripartite model (L. A. Clark & Watson, 1991). Factors emerged corresponding to each of the 3 posited first-order dimensions of negative affect, positive affect, and physiologic arousal. Nonetheless, some discrepancies were found between the observed data and the hypothesized tripartite model. First, the obtained physiologic arousal factor was best viewed as reflecting nonspecific somatic distress rather than physiologic arousal. Finally, although differentiable in the strictest statistical sense, all three domains were significantly correlated (.36 to.86, absolute value). In particular, contrary to the tripartite model, positive and negative affect covaried markedly (-.81 to -.86). Findings raise issues concerning the utility of the tripartite model as a heuristic framework for enhancing understanding of individual differences in normal mood as well as mood disorders.     

Eye movements during reading: some current controversies

For many researchers, eye-movement measures have become instrumental in revealing the moment-to-moment activity of the mind during reading. In general, there has been a great deal of consistency across studies within the eye-movement literature, and researchers have discovered and examined many variables involved in the reading process that affect the nature of readers' eye movements. Despite remarkable progress, however, there are still a number of issues to be resolved. In this article, we discuss three controversial issues: (1) the extent to which eye-movement behavior is affected by low-level oculomotor factors versus higher-level cognitive processes; (2) how much information is extracted from the right of fixation; and (3) whether readers process information from more than one word at a time.