Weighted minimum trace factor analysis

In the last decade several authors discussed the so-called minimum trace factor analysis (MTFA), which provides the greatest lower bound (g.l.b.) to reliability. However, the MTFA fails to be scale free. In this paper we propose to solve the scale problem by maximization of the g.l.b. as the function of weights. Closely related to the primal problem of the g.l.b. maximization is the dual problem. We investigate the primal and dual problems utilizing convex analysis techniques. The asymptotic distribution of the maximal g.l.b. is obtained provided the population covariance matrix satisfies sone uniqueness and regularity assumptions. Finally we outline computational algorithms and consider numerical examples.I wish to express my gratitude to Dr. A. Melkman for the idea of theorem 3.3.     

Religion and mental health among Nepal earthquake survivors in temporary tent villages

The aim of this study was to explore the relationship between mental health and the perceived importance of religion and the frequency of prayer among 200 children ages 10–18 years who lived in temporary camps for earthquake survivors in Nepal. The participants were examined using the Child Behavior Checklist (CBCL) 6–18 and were asked about the importance of religion in their lives. In contrast to expectation that high perceived importance of religion and prayer frequency have positive impacts on mental health after earthquakes, the results indicated significantly higher levels of withdrawal/depression. The group that prayed less frequently after the earthquakes had significantly higher scores for somatic symptoms, withdrawal/depression, anxiety/depression, social immaturity, internalising problems, and total CBCL scores. However, the clinical risk group (T score of 65 or higher in the CBCL total score), no significant difference according to the importance of religion showed and frequency of daily prayer.     

Does frequency trajectory influence word identification? A cross-task comparison

In a series of six experiments, the influence of frequency trajectory in visual word recognition was investigated. In Experiment 1, frequency trajectory was found to exert a strong and reliable influence on age of acquisition (AoA) ratings. In word reading (Experiment 2), lexical decision (Experiments 3 and 6), proper name decision (Experiment 4), progressive demasking (Experiment 5), and a multiple regression analysis of lexical decision times taken from the French Lexicon Project, the effect of frequency trajectory was not reliable. In contrast, in all the experiments and in the multiple regression analysis, cumulative frequency had a strong and reliable influence on word recognition times. The findings firmly establish that in alphabetic languages such as French, age-limited learning effects do not surface readily in word recognition. In contrast, the total exposure to words across the lifetime is a strong determinant of word recognition speed. The implications of the findings are discussed.     

Categorizing facial identities, emotions, and genders: attention to high- and low-spatial frequencies by children and adults

Three age groups of participants (5-6 years, 7-8 years, adults) matched faces on the basis of facial identity. The procedure involved either low- or high-pass filtered faces or hybrid faces composed from two faces associated with different spatial bandwidths. The comparison stimuli were unfiltered faces. In the three age groups, the data indicated a significant bias for processing of low-pass information in priority. In a second task, participants were asked to identify the emotion (smiling or grimacing) or gender (male or female) of hybrid high-pass/low-pass faces. Opposite results emerged in the two tasks irrespective of the age group; the gender discrimination task indicated a bias for low-pass information, and the emotion task indicated a bias for high-pass information. These differences suggest independent processing routes for functionally different types of information such as emotion, gender, and identity. These routes are already established by 5 years of age.     

The precise time course of lexical activation: MEG measurements of the effects of frequency, probability, and density in lexical decision

Visually presented letter strings consistently yield three MEG response components: the M170, associated with letter-string processing (Tarkiainen, Helenius, Hansen, Cornelissen, & Salmelin, 1999); the M250, affected by phonotactic probability, (Pylkk?nen, Stringfellow, & Marantz, 2002); and the M350, responsive to lexical frequency (Embick, Hackl, Schaeffer, Kelepir, & Marantz, 2001). Pylkk?nen et al. found evidence that the M350 reflects lexical activation prior to competition among phonologically similar words. We investigate the effects of lexical and sublexical frequency and neighborhood density on the M250 and M350 through orthogonal manipulation of phonotactic probability, density, and frequency. The results confirm that probability but not density affects the latency of the M250 and M350; however, an interaction between probability and density on M350 latencies suggests an earlier influence of neighborhoods than previously reported.     

A strict response criterion yields a mirror effect in the novelty paradigm

According to the novelty/encoding hypothesis (NEH; Tulving & Kroll, 1995), efficacy of encoding information into long-term memory depends on the movelty of the information. Recognition accuracy is higher for novel than for previously familiarized material. This novelty effect is not a mirror effect: the superiority of novel over familiar items is not found in the hit rates but only in the false-alarm rates. The main result in the present replication study was that novel hit rates were higher than familiar ones when the most confident responses were examined separately, and thus a mirror effect could be demonstrated for these data, for both the low- and the high-frequency words. Similarly, the word-frequency effect on hits was stronger when a stricter response criterion was applied. It was concluded that the novelty effect and the word-frequency effect are more similar to one another than has hitherto been thought.     

结构对称性汉字视觉识别特点的实验研究

用命名作业通过二个实验考察了结构对称性汉字的视觉识别特点,结果表明,汉字识别具有显著的结构对称性效应,识别结构对称性汉字的加工明显快于非对称性汉字,对称性效应与字频效应,笔画效应具有显著的交互作用,进一步的简单效应的分析表明,这种结构对称性效应在低频字中起作用,而在高频字中不起显著作用;在多笔画字中起作用,而在少毛画字中不起显著作用,这表明,对称性汉字中的具有冗余信息的格式塔部件促进地识别汉字的加     

How pigeons discriminate the relative frequency of events.

This study examined how pigeons discriminate the relative frequencies of events when the events occur serially. In a discrete-trials procedure, 6 pigeons were shown one light nf times and then another nl times. Next, they received food for choosing the light that had occurred the least number of times during the sample. At issue were (a) how the discrimination was related to two variables, the difference between the frequencies of the two lights, D = nf - nl, and the total number of lights in the sample, T = nf + nl; and (b) whether a simple mathematical model of the discrimination process could account for the data. In contrast with models that assume that pigeons count the stimulus lights, engage in mental arithmetic on numerons, or remember the number of stimuli, the present model assumed only that the influence of a sample stimulus on choice increases linearly when the stimulus is presented, but decays exponentially when the stimulus is absent. The results showed that, overall, the pigeons discriminated the relative frequencies well. Their accuracy always increased with the absolute value of the difference D and, for D > 0, it decreased with T. Performance also showed clear recency, primacy, and contextual effects. The model accounted well for the major trends in the data.     

Visual field differences in spatial frequency discrimination

Subjects discriminated between sine-wave gratings that differed by either +/-0.125 octaves (small difference) or +/-1.0 octaves (large difference). Baseline stimuli consisted of either 1.0 or 4.0 cycles per degree gratings. A left visual field advantage was obtained for the small difference in frequency, with no visual field advantages for the large difference in frequency. Similarly, moderate support for right versus left visual field advantages in processing high versus low spatial frequencies was found, although these interactions were not statistically significant. The results are discussed in light of Kosslyn's (1987) categorical and coordinate framework.     

Imagery Value,Subjective and Objective Frequency,Date of Entry into the Language,and Degree of Polysemy in a Sample of 998 French Words

A random sample of 998 lexical words was drawn from a dictionary of the French language. Two groups of subjects rated the words for imagery value (IV) and subjective frequency (SF). Despite substantial individual differences in the ratings, the subjective measures were highly reliable (α = 0.98 for both IV and SF). The relation between the standard deviation and the mean of the ratings can be described by a quadratic function (R = 0.93 for IV and R = 0.75 for SF). The independence of IV and frequency was confirmed. IV was found to be partially dependent on grammatical category (η = 0.50) and slightly dependent on polysemy. Date of entry into the language (DE) was correlated with objective and subjective frequency. The correlation between DE and IV was weak. The words and their characteristics are presented in the Appendix.