Perceptual scission of surface-lightness and illumination: An examination of the gelb effect

Summary An attempt was made to examine how the photometric equation: luminance (L)=albedo (A)×illuminance (I) could be solved perceptually when a test field (TF) was not seen as figure, but as ground. A gray disk with two black or white patches was used as the TF. Illuminance of the TF was changed over 2.3 log units and TF albedo was varied from 2.5 to 8.0 in Munsell value. Albedos of the black- and white-appearing patches were 1.5 and 9.5 in Munsell values, respectively. Two types of category judgments for apparent TF lightness (A) and apparent overall illumination (I) were made on the total of 40 TFs (5 illuminances×4 TF-albedos×2 patch-albedos). The results indicated that when the black patches were added to the TF, A was indistinguishable from I and when the white patches were placed on the TF, A and I could be distinguished from each other. The Gelb effect was interpreted as a manifestation of such A–I scission. It was concluded, therefore, that as far as the Gelb effect was observed, the perceptual system could solve the equation, L=A×I, in the sense that for a fixed L, the product of A and I would be constant.     

An experimental test of Jameson and Hurvich’s theory of brightness contrast1

Two hundred and fifty-two brightness functions for seven simultaneously presented black, gray, and white squares on black, gray, and white backgrounds approximated power curves with positive exponents when illuminance was varied in seven steps over 1.9 log fL. Mean exponents were significantly larger for whiter vs blacker squares and for squares on the white vs the gray background. Mean exponents also increased more for squares on white than on black or gray backgrounds. Finally, a white replacing a black background elicited increasingly larger décrémentai responses as the squares varied from black to white. Jameson and Hurvich’s opponent-process theory, tested by the experiment, was not predictive.     

Test Anxiety, Self-Awareness, and Cognitive Interference: A Process Analysis

ABSTRACT Participants performed a cognitive task under evaluative, self-awareness, and neutral conditions, Task performance was determined jointly by trait test anxiety and situational factors. Test anxiety led to poorer performance in both evaluative and self-awareness situations, relative to the neutral situation. We examined the cognitive activity variables that might mediate the effects of test anxiety and situational variables on performance, and identified a significant cognitive mediator of the main effect of test anxiety, but not for the Test Anxiety x Situation interaction effect. Therefore, the current experiment offered some support for Sarason's (1980) cognitive interference theory, as well as integrating test anxiety and self-awareness research.     

English Vowel Spaces Produced by Japanese Speakers: The Smaller Point Vowels’ and the Greater Schwas’

This study investigated how Japanese-speaking learners of English pronounce the three point vowels /i/, /u/, and /a/ appearing in the first and second monosyllabic words of English noun phrases, and the schwa /ə/ appearing in English disyllabic words. First and second formant (F1 and F2) values were measured for four Japanese speakers and two American English speakers. The hypothesis that the area encompassed by the point vowels in the F1-F2 vowel space tends to be smaller for the Japanese speakers than for the English speakers was verified. The hypothesis that the area formed by the three schwas in chicken{{chick\underline{e}n}}, spoonful{{spoonf{\underline{u}}l}}, and Tarzan{{Tarz\underline{a}n}} is greater for the Japanese speakers than for the English speakers and its related hypothesis were largely upheld. Implications for further research are briefly discussed.     

An integration of color and motion information in visual scene analyses

To analyze complex scenes efficiently, the human visual system performs perceptual groupings based on various features (e.g., color and motion) of the visual elements in a scene. Although previous studies demonstrated that such groupings can be based on a single feature (e.g., either color or motion information), here we show that the visual system also performs scene analyses based on a combination of two features. We presented subjects with a mixture of red and green dots moving in various directions. Although the pairings between color and motion information were variable across the dots (e.g., one red dot moved upward while another moved rightward), subjects' perceptions of the color-motion pairings were significantly biased when the randomly paired dots were flanked by additional dots with consistent color-motion pairings. These results indicate that the visual system resolves local ambiguities in color-motion pairings using unambiguous pairings in surrounds, demonstrating a new type of scene analysis based on the combination of two featural cues.     

Is Family Expressiveness as Reported by Mothers and Fathers Related to Children’s Social Anxiety Symptoms?

We examined family expressiveness as reported by mothers and fathers with respect to children’s report of social anxiety symptoms. Participants consisted of a clinical sample of 178 youth (8–16 years) and their parents. The sample was largely homogenous (163 Caucasians, 6 African American, 4 Hispanic, 5 Asian/Native American; 118 boys, 60 girls), and for analytic purposes, divided into two age groups: young children between 8 and 10 years and preadolescents and adolescents between 11 and 16 years. Youth completed the Social Anxiety subscale of the Multidimensional Anxiety Scale for Children and parents completed the Expressiveness subscale of the Family Environment Scale. The Expressiveness subscale measures the extent to which family members openly and directly express their emotions. We hypothesized that low levels of family expressiveness, as reported by mothers and fathers, would be associated with heightened symptoms of social anxiety for both age groups of the youth. Contrary to predictions, no significant associations were observed between young children’s social anxiety and expressiveness. For older children, however, maternal reports of family expressiveness were negatively related to social anxiety symptoms (as predicted) whereas paternal reports of family expressiveness were positively related to youth’s social anxiety symptoms (counter to predictions). This later finding suggests that the more expressive the father perceived the family to be, the higher the symptoms of social anxiety reported by the older youth. Findings are discussed in terms of differential perceptions of family expressiveness and socialization by mothers and fathers and gender role stereotypes.     

Impact of language on development of auditory-visual speech perception

The McGurk effect paradigm was used to examine the developmental onset of inter-language differences between Japanese and English in auditory-visual speech perception. Participants were asked to identify syllables in audiovisual (with congruent or discrepant auditory and visual components), audio-only, and video-only presentations at various signal-to-noise levels. In Experiment 1 with two groups of adults, native speakers of Japanese and native speakers of English, the results on both percent visually influenced responses and reaction time supported previous reports of a weaker visual influence for Japanese participants. In Experiment 2, an additional three age groups (6, 8, and 11 years) in each language group were tested. The results showed that the degree of visual influence was low and equivalent for Japanese and English language 6-year-olds, and increased over age for English language participants, especially between 6 and 8 years, but remained the same for Japanese participants. This may be related to the fact that English language adults and older children processed visual speech information relatively faster than auditory information whereas no such inter-modal differences were found in the Japanese participants' reaction times.     

The relationship between perceived surface-lightness and perceived illumination

Summary An attempt was made to specify the relationship between perceived surface lightness and perceived illumination under the stimulus conditions where different combinations of albedo and illuminance gave 10 approximately equal-luminance levels of a test field (TF) on three different (black-, gray- and white-appearing) backgrounds. Two types of category judgments for TF-lightness and overall illumination were made on the total of 94 TFs by 5 Ss. The results indicated that under the condition where achromatic surface colors appear, the perceptual scission which produces two different perceptual dimensions (lightness and perceived illumination) from one sort of stimulation (luminance) was clearly observed. The relation between the two judgments was consistent with the lightness-illumination invariance hypothesis: As lightness judgments (A) changed from darker to lighter, illumination judgments (I) shifted form brighter to dimmer, the sum of A and I being kept nearly invariant for a given luminance of the TF; the psychological relationship between lightness and illumination, A+I, changed as a linear function of the photometric combination of albedo and illuminance, log A+log I. It was also found that the albedo of the background was an important factor determining the extent of perceptual scission between lightness and illumination.     

Kinesthetic aspects of mental representations in the identification of left and right hands

Kinesthetic aspects of mental representations of one’s own hands were investigated. Line drawings showed a human hand in one of five versions, in which finger position and wrist rotation varied; each version occurred as a left and as a right hand, and could appear in any one of eight directions in the picture plane. The subject was required to make quick judgments of whether a left or a right hand was represented, under three conditions of head tilt (left, upright, right). Reaction time varied systematically, reflecting the time required to move one’s own hand into congruence with the stimulus. Head tilt influenced the subjective reference frame of mental rotation when the degree of head tilt was 60 deg.     

Nicotinic cholinergic synaptic mechanisms in the ventral tegmental area contribute to nicotine addiction

Tobacco use is a major health problem that is estimated to cause 4 million deaths a year worldwide. Nicotine is the main addictive component of tobacco. It acts as an agonist to activate and desensitize nicotinic acetylcholine receptors (nAChRs). A component of nicotine's addictive power is attributable to actions on the mesolimbic dopaminergic system, which serves a fundamental role in the acquisition of behaviors that are inappropriately reinforced by addictive drugs. Here we show that nicotine, in the same concentration and time ranges as obtained from tobacco, has three main actions that regulate the activity of midbrain dopamine (DA) neurons. Nicotine first activates and then desensitizes nAChRs on the DA neurons. This process directly excites the DA neurons for a short period of time before the nAChRs desensitize. Nicotine also enhances glutamatergic excitation and decreases GABAergic inhibition onto DA neurons. These events increase the probability for synaptic plasticity, such as long-term potentiation. The short-lived direct excitation of the DA neurons coupled with the enhanced glutamatergic afferent activity provides the presynaptic and postsynaptic coincidence necessary to initiate synaptic potentiation. In total, these synaptic events lead to a relatively long-lasting heightened activity of midbrain DA neurons. Consistent with other summarized studies, this work indicates that the synaptic changes normally associated with learning and memory can be influenced and commandeered during the nicotine addiction process.