Individual half-judgment brightness functions

Nine Ss made half-judgments of each of nine brightness standards. Individual half-judgment brightness functions were constructed, one for each of the two threshold forms of the power law. The ω-Law (translation on the psychological axis) provided a better fit to the half-judgment data than did the ?-Law (translation on the intensity axis). A test of scale consistency for the fractionation method was confounded with the power law hypothesis, but the data are interpreted as providing fair support for the method independent of the form of the power law. The effect of Standard on exponent estimates was significant for both forms of the law, and the effect of Standard on threshold estimates was significant for the ?-Law but not for the ω-Law. Both forms of the law contain a so-called threshold parameter, but the interpretation of this parameter as a threshold was rejected for the ?-Law and accepted for the ω-Law.     

Invariance tests for bisection and fractionation scaling

If we are to accept the power function as the psychophysical law, then estimates of the exponent of a particular form of the power law should be independent of changes in basic independent variables. In the present study, various power law hypotheses were tested for the bisection and fractionation scaling of brightness. The results indicated that for bisection, estimates of exponents were dependent on the particular interval bisected, suggesting rejection of the simple power law for bisection. For fractionation, two additional forms of the power law were tested, each form involving a threshold parameter. One was the Φ-law (involving a translation on the intensity axis), and the other was the ψ-law (involving a translation on the psychological axis). The Φ-law provided a poor fit to the data, whereas the ψ-law appeared to fit well for at least one S. Analysis for individuals showed that for all five Ss, the variance due to standards was appreciably larger for the Φ-law.     

Color adaptation in a yellow-blue system: proof of a simple numerical relationship]

Three axes in color space are specified: a (unique) yellow - (unique) blue axis, a (unique) green - magenta axis and brightness. Based on the two chromatic axes two linear opponent colors systems are defined: a red/green-system and a yellowish/bluish-system. A numerical relation is presented to describe color adaptation for the yellowish/bluish-system under adaptation to (unique) yellow and (unique) blue: two pairs of color stimuli are equivalent with regard to the yellowish/bluish-system - consisting of a test stimulus and an adaptation stimulus, respectively - if the ratios from the yellowish/bluish-coordinates of test stimulus and adaptation stimulus are identical. A control of brightness and the red/green-system is presupposed. For several (unique) yellow and (unique) blue adaptation stimuli it is examined how a test stimulus that appears neither yellowish nor bluish changes its location on the (unique) yellow - (unique) blue axis within color space. Three observers take part in the experiment. For each observer a plane of constant brightness and the opponent colors axes are estimated experimentally. The data show that the ratios from the yellowish/bluish coordinates of test stimulus and adaptation stimulus are essentially constant. The results are compared with analogous data for the red/green-system. The findings provide evidence for the specification of the three phenomenal axes. The specification is discussed with regard to Hering's opponent colors theory and Krauskopf's three "cardinal" axes [1982, Vision Research, 22, 1123-1131].     

Dominance as a function of cue similarity: A test of the intrinsic cue dominance model

A nonselective model postulating intrinsic cue dominance was tested in simultaneous discrimination tasks involving reversal on one dimension. In this procedure two dimensions are relevant throughout training; however, following initial discrimination training the reward contingency is reversed for one dimension but maintained for the other. Cue dominance was assessed following acquisition of reversal by the use of opposed-cues test trials, and was defined as a greater number of choices of the test compound containing the positive cue of the reversed dimension than of the test compound containing the positive cue of the maintained dimension. In Experiment I, brightness cues dominated orientation cues. In Experiment II, which employed two different sets of relevant cues, more disparate brightness cues dominated the orientation cues for one set and orientation cues dominated less disparate brightness cues for the other. From this, it was concluded that dominance is a function of relative cue similarity.     

The effect of small brightness differences on the after-effect of seen movement

Two experiments are reported. In the first experiment the after-effect of seen movement has been shown to occur with a measurable duration when there was a small difference in brightness between adjacent parts of the stimulus pattern. In the second experiment the duration of the after-effect was observed under two conditions of brightness difference; one small and the other relatively large. The difference between the durations of the aftereffect for the two conditions of brightness difference was significant. Results from these experiments have been discussed together with data from an earlier study in which the effects of brightness differences of greater magnitude were investigated. The probable function of the duration of the after-effect with respect to brightness differences over the full range of differences has been considered.     

Testing the attentional model of brightness contrast with relative area and figure-ground organization unconfounded

Using gray-white metric patterns, for which figure-ground relationships had been previously determined, several features of an attentional theory of brightness contrast were investigated. Experiment I, involving three subjects and the method of constant stimuli, showed that ground, the unattended area, could be reliably perceived as brighter; responses were affected by both the type of pattern and level of contrast ratio. Experiment II, involving 40 subjects and the method of magnitude estimation, used metric patterns for which attentional factors were not confounded with relative area. The results supported the first study and further indicated the primary involvement of relative area rather than focus of attention in brightness contrast.

     

Comparison of associations to vowel speech sounds by English and Spanish speakers

Many psycholinguists have studied associations to vowel speech sounds. It appears that associations involving brightness and size are related to the manner in which the vowels are articulated. That is, high front vowels are judged to be bright and small, and low back vowels are judged to be dim and large. In an extension of a study by Greenberg and Jenkins (1966), 40 English-speaking and 40 Spanish-speaking adults rated nine audiotaped vowel sounds on 23 dimensions. The front-back distinction was again found for both groups. In addition, ratings for all nine vowels were similar for the two groups, which has implications for the cross-cultural universality of these associations.     

Local brightness mechanisms sketch out surfaces but do not fill them in: psychophysical evidence in the Kanizsa square.

In two experiments, brightness enhancement of the illusory surface in the Kanizsa square was investigated by means of a brightness matching procedure. The results show that specific properties of the inducing elements such as size, spacing, and luminance have effects on the matching threshold that are similar to those previously obtained in experiments on simultaneous contrast. The data from a third experiment demonstrate that increment thresholds measured within the Kanizsa square are elevated when the target is flashed on a position close to the inducing elements. The thresholds decrease considerably in the center of both test and control figures (representing or not representing an illusory square). These observations suggest that low-level mechanisms are likely to explain local brightness differences within the configurations but not global figure brightness. In other words, local contrast seems to generate brightness information that "sketches out" surfaces at their surrounds but does not "fill" them "in."     

Temporal stability of the Czech translation of the Satisfaction with Life Scale: test-retest data over one week

The present study supplemented the limited 1999 psychometric data by Lewis, et al. on the Czech translation of the Satisfaction With Life Scale by examining the temporal stability of the measure over a 1-wk. period for 64 Czech undergraduate university students. Analysis indicated stability across the two administrations was very high (r=.90), and there was no significant change between Time 1 (M=23.7, SD=5.1) and Time 2 (M=24.1, SD=5.5). Short-term test-retest reliability of this Czech translation is supported.     

Local brightness mechanisms sketch out surfaces but do not fill them in: Psychophysical evidence in the Kanizsa square

In two experiments, brightness enhancement of the illusory surface in the Kanizsa square was investigated by means of a brightness matching procedure. The results show that specific properties of the inducing elements such as size, spacing, and luminance have effects on the matching threshold that are similar to those previously obtained in experiments on simultaneous con trast. The data from a third experiment demonstrate that increment thresholds measured within the Kanizsa square are elevated when the target is flashed on a position close to the inducing elements. The thresholds decrease considerably in the center of both test and control figures (representing or not representing an illusory square). These observations suggest that low-level mechanisms are likely to explain local brightness differences within the configurations but not global figure brightness. In other words, local contrast seems to generate brightness information that “sketches out” surfaces at their surrounds but does not “fill” them “in.”     

Unsupervised category learning with integral-dimension stimuli

Despite the recent surge in research on unsupervised category learning, the majority of studies have focused on unconstrained tasks in which no instructions are provided about the underlying category structure. Relatively little research has focused on constrained tasks in which the goal is to learn predefined stimulus clusters in the absence of feedback. The few studies that have addressed this issue have focused almost exclusively on stimuli for which it is relatively easy to attend selectively to the component dimensions (i.e., separable dimensions). In the present study, we investigated the ability of participants to learn categories constructed from stimuli for which it is difficult, if not impossible, to attend selectively to the component dimensions (i.e., integral dimensions). The experiments demonstrate that individuals are capable of learning categories constructed from the integral dimensions of brightness and saturation, but this ability is generally limited to category structures requiring selective attention to brightness. As might be expected with integral dimensions, participants were often able to integrate brightness and saturation information in the absence of feedback—an ability not observed in previous studies with separable dimensions. Even so, there was a bias to weight brightness more heavily than saturation in the categorization process, suggesting a weak form of selective attention to brightness. These data present an important challenge for the development of models of unsupervised category learning.     

Unsupervised category learning with integral-dimension stimuli

Despite the recent surge in research on unsupervised category learning, the majority of studies have focused on unconstrained tasks in which no instructions are provided about the underlying category structure. Relatively little research has focused on constrained tasks in which the goal is to learn predefined stimulus clusters in the absence of feedback. The few studies that have addressed this issue have focused almost exclusively on stimuli for which it is relatively easy to attend selectively to the component dimensions (i.e., separable dimensions). In the present study, we investigated the ability of participants to learn categories constructed from stimuli for which it is difficult, if not impossible, to attend selectively to the component dimensions (i.e., integral dimensions). The experiments demonstrate that individuals are capable of learning categories constructed from the integral dimensions of brightness and saturation, but this ability is generally limited to category structures requiring selective attention to brightness. As might be expected with integral dimensions, participants were often able to integrate brightness and saturation information in the absence of feedback--an ability not observed in previous studies with separable dimensions. Even so, there was a bias to weight brightness more heavily than saturation in the categorization process, suggesting a weak form of selective attention to brightness. These data present an important challenge for the development of models of unsupervised category learning.     

Individual differences in pulse brightness perception

When brightness-pulse duration relations are studied with a simultaneous brightness discrimination procedure, three classes of observers emerge (Bowen & Markell, 1980). These classes are defined by whether or not observers perceive temporal brightness enhancement (the Broca-Sulzer effect) under two asynchrony conditions for pulses to be compared: simultaneous onset and simultaneous offset. Type A observers perceive brightness enhancement for both asynchrony conditions; Type B observers perceive brightness enhancement for simultaneous offset of pulses but not for simultaneous onset; Type C observers do not generate the Broca-Sulzer effect under either asynchrony condition. Here we present supplementary measures on observers of all three types: (1) magnitude estimation of the brightness of single pulses of light of varying duration, (2) modulation sensitivity for sin~wave flicker, and (3) contrast sensitivity for moving sine-wave gratings. The magnitude estimation data differentiated the three types of observers, but flicker and motion sensitivity did not. The three classes of observers probably differ in the perceptual criteria they employ in judging the brightness of isolated pulses of light; they probably do not differ in their underlying neurophysiological responses.     

The effect of overtraining on transfer between tasks involving the same stimulus dimension

Two experiments are reported in which transfer effects between two discrimination tasks are examined following differing amounts of training on the first task. The two tasks were a conditional (successive) discrimination involving black/white cues, and a simultaneous brightness discrimination involving the same black/white cues.

In Experiment I the conditional task was presented first and in Experiment II the simultaneous task was presented first. The results of Experiment I show overall negative transfer which is not directly related to the amount of training. The results of Experiment II, however, reveal positive transfer although again the amount of training produced no significant effect. These seemingly discrepant findings are explained in terms of the difficulty of the conditional task and the development of rigid position stereotypes. It is argued that the concept of frustration-instigated behaviour is necessary to account for the results.     

Effects of hue,brightness, contrast with background,and observation time on figural dominance in ambiguous patterns

Ambiguous patterns composed of two alternate crosses of different hues and brightness on two different brightness backgrounds were viewed for 120 sec by 10 female college students. Each subject observed 92 pattern presentations (23 patterns, each pattern presented in 2 orientations and on each of 2 backgrounds). Effects of hue and brightness contrast with background were clearly demonstrated: blue was the most dominant, red the least, and green and yellow located in between. Brightness contrast of patterns with background accentuated figural dominance of the darker figures. The number of alternations increased over the observation time for hues of equal brightness; however, the relation of this measure to total duration of seeing a figure in studies of figural dominance is unclear. Theories of neural satiation, fatigue, and interaction were used in interpreting the results.     

Deformation of the useful visual field with state of vigilance,task priority,and central task complexity

In a dual-task situation, peripheral perception can deteriorate due to different variables related to the experimental situation, such as central task complexity and the relative priority given to the two tasks. Recent studies have also shown that individual characteristics (such as the state of vigilance) can alter the useful visual field. The ability to perceive signals presented at different places in the visual field decreases in situations that lead to episodes of low vigilance. In Exp. 1, 27 subjects (18-29 years) had to perform a monotonous and prolonged dual-monitoring task involving central and peripheral vision. The test was carried out with two different sets of instructions regarding priority: the more important task was either the central task or the peripheral one. In Exp. 2, 18 subjects (18-30 years) performed the same test, but this time with two levels of complexity of the central task, either a simple monitoring activity or the same monitoring task coupled with a counting activity. Elliptical interpolation of the data enabled assessment of the deformation of the useful visual field in both experiments. The analysis of the parameters of the elliptical model indicated that the useful visual field mainly shrinks on the vertical axis, as the individual becomes drowsy. The useful visual field also shrinks on the horizontal axis when the peripheral task has priority and the monitoring activity is prolonged, or when the central task is complex.     

Stimulus dimensionality and temporal repetition

Two experiments involving temporal repetition of tachistoscopically presented visual stnnuh are reported. Experiment I employed an alphabet of four straight lines presented one, two, or four times. Experiment II employed three stimulus sets, such that the stimuli varied in size, brightness, or both, with the forms being presented either once or four times. The Ss made four-choice identification responses. Results indicate that multidomensionality is not a necessary condition for better Identification performance with multiple observations, and that this differential in favor of multiple observations persists after many, many experimental sessions.     

Binocular processing of brightness information: a vector-sum model

The relation between monocular and binocular brightness was examined. Clear evidence was found that the interaction between visual channels in binocular processing of brightness information implicates both an apparent averaging of monocular brightness when they are grossly different and a partial summation when they approach equality. A vector-sum model is shown to predict these properties. A nonmetric method was used to fit such a model to data from three experiments in each of which 15 subjects estimated brightness of binocularly fused targets. Magnitude estimation was used in two experiments, and cateogry ratings were obtained in the third experiment. When it was assumed only that subjects' responses were monotone with perceived brightness, estimates of the model's parameters from the data of the three experiments were almost identical, indicating that results from magnitude estimati;n and category rating can converge once nonlinear response functions are eliminated.     

Activation of lexical and syntactic target language properties in translation

Is reading for translation equal to reading in monolingual contexts? Horizontal/parallel theories of translation propose that normal reading and reading for translation differ because the translator engages in partial reformulation while reading for translating the source text. In contrast, vertical/serial theories assume that the translators first extract the meaning of the message, and only then they proceed to reformulate it. In two experiments, we manipulated lexical and syntactic properties of the target language (TL) while translators read for repetition or for translation. On-line sentence comprehension was affected by the lexical frequency of words in the TL (Experiment 1) and the syntactic congruency between the source language (SL) and TL sentences (Experiment 2). However, the influence of lexical and syntactic TL properties was restricted to the reading for translation task. According to our results, the horizontal view of translation includes code-to-code links between the SL and TL involving at least the lexical and syntactic level of processing.     

Validity evidence and measurement equivalence for the Dutch translation of the conditional reasoning test for aggression

The Conditional Reasoning Test for Aggression (CRT-A) indirectly measures the implicit motive to aggress by engaging respondents in inductive reasoning tasks. Most research involving the CRT-A has been based on the original English version of the test with most data being collected in the United States. The purpose of the current paper is to evaluate the psychometric properties of a Dutch translation of this test and to examine if it could be used to predict measures of integrity. In the first of two studies, we evaluated the psychometric properties and measurement equivalence of the CRT-A across US and Dutch samples. In the second study, we examined validity evidence for the Dutch version of the CRT-A. Results from Study 1 indicated that the test was mostly equivalent across cultures (i.e. limited differential item functioning was detected). Results from Study 2 demonstrated that the Dutch version of the CRT-A was correlated with measures of behavioral integrity and provided incremental prediction of integrity over and above traditional self-report measures of explicit personality traits. We discuss the implications for using CRTs across different cultures and languages.