Association of race and color with mean IQ across nations

This study investigated the correlation of both race and skin color in the distribution of mean IQ for 129 countries with primarily indigenous populations. Skin color correlated most highly with mean IQ across the Caucasoid countries (r = -.86), somewhat less across the Mongoloid countries (r = -.66), and nonsignificantly across the Negroid countries (r = .06). When the Negroid and Caucasoid countries were combined, both race and skin color yielded high correlations with IQ (r = .87, -.95, respectively). When the Negroid and Mongoloid countries were combined, both race and skin color yielded high correlations with IQ (r = .91, -.91, respectively). When Caucasoid and Mongoloid countries were combined, skin color yielded a high correlation, but race did not correlate significantly with IQ. The greater importance of Negroid race was regarded as congruent with the 1998 generalization of Jensen that the genetic distance between Mongoloids and Caucasoid is less than the genetic distance of these two groups from Negroid.     

The roles of sequencing and verbal working memory in sentence comprehension deficits in Parkinson's disease

Studies of sentence comprehension deficits in Parkinson's disease (PD) patients suggest that language processing involves circuits connecting subcortical and cortical regions. Anatomically segregated neural circuits appear to support different cognitive and motor functions. To investigate which functions are implicated in PD comprehension deficits, we tested comprehension, verbal working memory span, and cognitive set-switching in a non-linguistic task in 41 PD patients; we also obtained speech measurements reflecting motor sequencing processes that may be involved in articulatory rehearsal within working memory. Comprehension of sentences with center-embedded or final relative clauses was impaired when they could not be understood from lexical semantic content alone. Overall comprehension error rates correlated strongly with impaired set-switching and significantly with reduced working memory span and speech motor sequencing deficits. Correlations with comprehension of different sentence structures indicate that these impairments do not represent a single deficit; rather, PD comprehension deficits appear to arise from several independent mechanisms. Deficits in cognitive set-switching or underlying inhibitory processes may compromise the ability to process relative clauses. Deficits in verbal working memory appear to impair comprehension of long-distance dependencies. Speech sequencing correlated with neither set-switching nor verbal working memory span, consistent with their being supported by independent, segregated cortico-subcortical circuits.     

Rational Imagination and Modal Knowledge

How do we know what's (metaphysically) possible and impossible? Arguments from Kripke and Putnam suggest that possibility is not merely a matter of (coherent) conceivability/imaginability. For example, we can coherently imagine that Hesperus and Phosphorus are distinct objects even though they are not possibly distinct. Despite this apparent problem, we suggest, nevertheless, that imagination plays an important role in an adequate modal epistemology. When we discover what is possible or what is impossible, we generally exploit important connections between what is possible and what we can coherently imagine. We can often come to knowledge of metaphysical modality a priori.     

Phase-dependent synaptic changes in the hippocampal CA1 field underlying extinction processes in freely moving rats

Recent studies focus on the functional significance of a novel form of synaptic plasticity, low-frequency stimulation (LFS)-induced synaptic potentiation in the hippocampal CA1 area. In the present study, we elucidated dynamic changes in synaptic function in the CA1 field during extinction processes associated with context-dependent fear memory in freely moving rats, with a focus on LFS-induced synaptic plasticity. Synaptic transmission in the CA1 field was transiently depressed during each extinction trial, but synaptic efficacy was gradually enhanced by repeated extinction trials, accompanied by decreases in freezing. On the day following the extinction training, synaptic transmission did not show further changes during extinction retrieval, suggesting that the hippocampal synaptic transmission that underlies extinction processes changes in a phase-dependent manner. The synaptic potentiation produced by extinction training was mimicked by synaptic changes induced by LFS (0.5 Hz) in the group that previously received footshock conditioning. Furthermore, the expression of freezing during re-exposure to footshock box was significantly reduced in the LFS application group in a manner similar to the extinction group. These results suggest that LFS-induced synaptic plasticity may be associated with the extinction processes that underlie context-dependent fear memory. This hypothesis was supported by the fact that synaptic potentiation induced by extinction training did not occur in a juvenile stress model that exhibited extinction deficits. Given the similarity between these electrophysiological and behavioral data, LFS-induced synaptic plasticity may be related to extinction learning, with some aspects of neuronal oscillations, during the acquisition and/or consolidation of extinction memory.     

Finding a face in a face-like object

Humans have the tendency to perceive a face even in a non-living object. Previous studies report that people perceive facial features and even interpret a personality in a car front. Following these findings, we investigated whether the perception of a face in a face-like object is mediated by human face processing, which involves both featural and configural processing. In our experiment, participants were presented with 30 face-like objects and were asked about the existence of facial features, the intensity of typicality/distinctiveness, and the intensity of facial expression. Using multiple regression analysis, which predicts the perception of a face in a face-like object, we found that the existence of eyes was a significant predictor of variance in perceiving a face in a face-like object.     

Do postpartum anxiety and breastfeeding self-efficacy and bonding at early postpartum predict postpartum depression and the breastfeeding method?

We investigated whether postpartum anxiety (PPA) and breastfeeding self-efficacy and bonding at the early postpartum period can be used to predict postpartum depression and the breastfeeding method, and we sought to identify factors related to postpartum depression. Of the 510 eligible women, 185 (36%) returned the questionnaire on all three occasions (1 day, 3 days, and 1 month after childbirth). The mothers' progress on the State-Trait Anxiety Inventory (STAI), Breastfeeding Self-Efficacy Scale Short Form (BFSES-SF), and Postnatal Bonding Questionnaire (PBQ) was observed over three periods. A repeated-measures ANOVA revealed that the mothers at high risk of developing postpartum depression (PPD) were those who did not show an increase in BFSES-SF score at early postpartum, and mothers whose bonding disorders have deteriorated rapidly. The results of the logistic regression analysis revealed a significant difference in employment as a factor related to postpartum depression. Compared to Regular, Part-time status was 4.4 times more likely and Unemployed status was 2.3 times more likely to cause postpartum depression. For the early detection of PPD, it is necessary to identify (1) mothers who do not show an increase in the BFSES-SF score, (2) mothers whose bonding disorders have deteriorated rapidly, and (3) part-time or unemployed mothers as characteristic of postpartum depression.     

Measurement of visual memory span by means of the recall of dot-in-matrix patterns

A method for the study of visual memory span is described. The results of two dot-in-matrix experiments indicated that the patterns of larger matrix size were more difficult to recall, but the effect of visual angle was not significant. Visual memory span could be represented by the number of dota in the 5 by 6 or 6 by 6 pattern that a subject perfectly recalled with a probability of .5, since the proportion of recalled patterns was a monotonie decreasing function of the number of dots. This method can be used in group experiments without consideration of the differences in visual angles caused by the locations of subjects. The selection of appropriate presentation times and the distinction between verbal and visual memory spans are discussed.     

Interhemispheric communication involving multiple tasks: A study of children with dyslexia

The study investigated whether inefficient interhemispheric communication is involved in developmental dyslexia using multiple tasks. A finger localization task, rhyming judgment task, primed lexical decision task, and a visual half-field presentation paradigm were used. Nineteen dyslexic children (mean age = 13.1 years) were compared with 26 chronological age-matched normal children. Although the dyslexic group demonstrated significantly slower and less accurate performance in all three tasks, there was no significant group difference in term of interhemispheric communication. However, priming effects demonstrated by the dyslexic group (p < .05) further indicate that their reading problems may stem from the word retrieval process from the long term memory.     

Quantitative and structural factors in the judgment of pattern complexity

The processes underlying judgment of pattern complexity were investigated using patterns containing eight dots in a 4 × 4 matrix. Thirty-two subjects rated the complexity of 140 patterns that were taken from patterns generated by 12 other subjects in a preliminary experiment. Factor analysis of mean complexity ratings and 12 physical variables, which objectively described configuration of dots, revealed a “quantitative factor” and a “structural factor.” Mean complexity loaded on both factors. Multiple regression analysis showed that the mean complexity was well predicted by combination of a quantitative variable with a structural variable. Analysis of individual data also suggested that individual differences in complexity judgment could be explained by the weights on these two factors. In addition, a rating experiment was carried out in which 60 patterns were presented in limited stimulus durations (50 msec, 200 msec, 1 sec, or 4 sec). The quantitative variables were highly correlated with the complexity ratings in all conditions, whereas the structural variables affected the ratings in long durations but not in short durations. These results support the view that visual complexity is judged through two processes: One is a fast process that evaluates quantitative aspects in a stimulus pattern, and the other is a slow process that detects the structure in the pattern.     

Plasticity of ability to form cross‐modal representations in infant Japanese macaques

In a previous study, Adachi, Kuwahata, Fujita, Tomonaga & Matsuzawa demonstrated that infant Japanese macaques (Macaca fuscata) form cross‐modal representations of conspecifics but not of humans. However, because the subjects in the experiment were raised in a large social group and had considerably less exposure to humans than to conspecifics, it was an open question whether their lack of cross‐modal representation of humans simply reflected their lower levels of exposure to humans or was caused by some innate restrictions on the ability. To answer the question, we used the same procedure but tested infant Japanese macaques with more extensive experience of humans in daily life. Briefly, we presented monkeys with a photograph of either a monkey or a human face on an LCD monitor after playing a vocalization of one of these two species. The subjects looked at the monitor longer when a voice and a face were mismatched than when they were matched, irrespective of whether the preceding vocalization was a monkey's or a human's. This suggests that once monkeys have extensive experience with humans, they will form a cross‐modal representation of humans as well as of conspecifics.