Signal-detection models for multidimensional stimuli: Probability distributions and combination rules

Probabilistic independence among multiple random variables (e.g., among the outputs of multiple spatial-frequency channels) has been invoked to explain two effects found with many kinds of stimuli: increments in detection performance due to “probability summation” and decrements in detection and identification performance due to “extrinsic uncertainty.” Quantitative predictions of such effects, however, depend on the precise assumptions. Here we calculate predictions from multidimensional signal-detection theory assuming any of several different probability distributions characterizing the random variables (including two-state, Gaussian, exponential, and double-exponential distributions) and either of two rules for combining the multiple random variables into a single decision variable (taking the maximum or summing them). In general, the probability distributions predicting shallower ROC curves predict greater increments due to summation but smaller decrements due to extrinsic uncertainty. Some probability distributions yield steep-enough ROC curves to actually predict decrements due to summation in blocked-summation experiments. Probability distribution matters much less for intermixed-summation than for blocked-summation predictions. Of the two combination rules, the sum-of-outputs rule usually predicts both greater increments due to summation and greater decrements due to extrinsic uncertainty. Put another way, of the two combination rules, the sum-of-outputs rule usually predicts better performance on the compound stimulus under any condition but worse performance on simple stimuli under intermixed conditions.     

Illusory contours in line patterns with apparent depth due to either perspective or overlay

An illusory contour along a partially delineated border in the form of an apparent 'outside' corner due to perspective was as strong as one along a similarly delineated border in the form of an edge due to overlay. An illusory contour along a border in the form of an apparent 'inside' corner, due probably to both perspective and overlay, was stronger than either. These outcomes suggest that apparent stratification from overlay is not necessary for the occurrence of illusory contours. They also accord with the view that apparent depth due to overlay or to perspective is equally effective in rendering partially delineated borders more prominent and, in consequence, the illusory contours that form along them stronger.     

Modeling Rater Disagreement for ADHD: Are Parents or Teachers Biased?

The present study is the first to utilize twin modeling to examine whether parent-teacher disagreement for ADHD ratings is due to parent or teacher bias, or due to raters observing different but valid ADHD behaviors. A joint analysis was conducted with 106 twin pairs, including twins selected for ADHD and control twin pairs. Total ADHD scores were analyzed using multiple rater models that estimate genetic and environmental contributions common to both raters and unique to each rater. Results suggest that 1) disagreement in ADHD ratings is strongly due to parents and teachers observing different ADHD behaviors, some of which is valid and some of which is due to bias, and 2) parents may be more biased than teachers in their ADHD ratings.     

The reality of racial differences: A rejoinder with new evidence

The criticisms of my race differences paper are considered within the following questions: (1) Do the racial differences exist as described or are they due entirely to faulty measurement or reporting? (2) Are the racial differences due partly to genetic factors as suggested or are they due entirely to environmental influences? (3) Does the r/K framework provide a good fit to the data or is some other framework more useful? Special attention is given to the issue of whether the racial differences are due to the genes or to social class and several lines of evidence are brought to bear to support the hypothesis that some of the differences are genetic. For example, inbreeding depression scores calculated from Japanese cousin marriages on the WISC are shown to predict black-white difference scores on the WISC-R.     

Source dependence in the valuation of objects

We ran two experiments to test whether people value objects more highly when they obtain those objects due to exemplary performance at a task. In the first, subjects who believed they had obtained a prize due to their performance on a classroom exercise valued it more highly than those who believed they had obtained it by chance. In the second, subjects who obtained a prize due to exemplary performance on a task valued it more highly than those who obtained it due to their poor performance. In both experiments, this ‘source dependence’ effect is approximately equal in strength to the endowment effect, which compares the valuation of subjects with and without the prize. We suggest a possible explanation for this source-dependence effect based on associationism, and rule out two alternative explanations.     

Central deafness and subcortical motor aphasia

Clinical and autopsy studies were made on a right-handed man who had central deafness and subcortical motor aphasia, and the literature on central deafness and on subcortical motor aphasia was analyzed. Central deafness is due to bilateral destruction of the primary auditory cortex. It is sometimes difficult to distinguish from word deafness and from auditory agnosia, which are due to pathology in other parts of the temporal lobes. There is almost always some preserved hearing in central deafness, possibly from some auditory pathway other than the classical pathway. In this patient the subcortical motor aphasia was due to bilateral destruction of the motor cortex for the mouth and throat. In some other cases subcortical motor aphasia was due to the same pathology that usually causes Broca's aphasia; in these cases the unexpected preservation of writing was perhaps related to some difference in how language functions were organized in the brain.     

Rheoencephalographic examinations of a patient with "coughing syncopes"--a contribution to etiology]

This is a report of a patient showing the clinical picture of syncopes due to coughing, who has been examined by rheoencephalography. Three different varitions of syncopes due to coughing are discussed with particular reference to the factors involved.     

Impact of group rejections from a physical activity on physical self-esteem among university students

This study examined the effects of trait physical self-esteem (TPSE) and reasons for group rejections upon state physical self-esteem (SPSE) in a social psychology experiment. Two vignettes were prepared for students to imagine themselves being rejected from a group physical activity. In one vignette, students were rejected by chance, whereas in the other, due to physical incapability. The results indicated that SPSE did not change significantly after rejection by chance, but that SPSE decreased significantly after rejection due to physical incapability. When the sample was divided to subgroups, high TPSE students decreased SPSE to the same level as low TPSE students, and the magnitude of decrease in high TPSE students was even larger than that in low TPSE students after rejection due to physical incapability. The similar pattern was observed in the comparison between male and female students, whereas SPSE of Physical Education major students did not drop as much after rejection due to physical incapability. Contrary to previous research, high TPSE failed to protect the decline of SPSE after group rejections particularly due to physical incapability. The involvement of the importance theory, coping strategies, and sources of rejections needs to be investigated further. Educational implications of the findings are discussed.     

Individual differences in vulnerability to subjective time distortion1

Time duration is perceived to be longer when accompanied by dynamic sensory stimulation than when accompanied by static stimulation. This distortion of time perception is thought to be due to the acceleration of an internal pacemaker that has been assumed to be the main component of temporal judgments. In order to investigate whether the function of the internal pacemaker is modality dependent or independent, we examined the correlation of visual flicker and auditory flutter effects on a temporal production task. While seeing a 10‐Hz visual flicker or hearing a 10‐Hz auditory flutter, participants estimated a duration of 2500 ms as accurately as possible by pressing a button. The results showed a significant within‐individual correlation between the time distortion due to visual flicker and that due to auditory flutter. Additionally, we found that time distortion due to auditory flutter tended to be larger in female participants than in male participants. These results suggest that the mechanisms underlying subjective time dilation are similar between vision and audition within individuals, but that they vary across individuals.     

Left-handedness: a marker for decreased survival fitness

Life span studies have shown that the population percentage of left-handers diminishes steadily, so that they are drastically underrepresented in the oldest age groups. Data are reviewed that indicate that this population trend is due to the reduced longevity of left-handers. Some of the elevated risk for sinistrals is apparently due to environmental factors that elevate their accident susceptibility. Further evidence suggests that left-handedness may be a marker for birth stress related neuropathy, developmental delays and irregularities, and deficiencies in the immune system due to the intrauterine hormonal environment. Some statistical and physiological factors that may cause left-handedness to be selectively associated with earlier mortality are also presented.     

Intrusion errors in visuospatial working memory performance

This study tested the hypothesis that failure in active visuospatial working memory tasks involves a difficulty in avoiding intrusions due to information that is already activated. Two experiments are described, in which participants were required to process several series of locations on a 4 x 4 matrix and then to produce only the final location of each series. Results revealed a higher number of errors due to already activated locations (intrusions) compared with errors due to new locations (inventions). Moreover, when participants were required to pay extra attention to some irrelevant (non-final) locations by tapping on the table, intrusion errors increased. Results are discussed in terms of current models of working memory functioning.     

Visual awareness due to neuronal activities in subcortical structures: a proposal

It has been shown that visual awareness in the blind hemifield of hemianopic cats that have undergone unilateral ablations of visual cortex can be restored by sectioning the commissure of the superior colliculus or by destroying a portion of the substantia nigra contralateral to the cortical lesion (the Sprague effect). We propose that the visual awareness that is recovered is due to synchronized oscillatory activities in the superior colliculus ipsilateral to the cortical lesion. These oscillatory activities are normally partially suppressed by the inhibitory, GABAergic contralateral nigrotectal projection, and the destruction of the substantia nigra, or the sectioning of the collicular commissure, disinhibits the collicular neurons, causing an increase in the extent of oscillatory activity and/or synchronization between activities at different sites. This increase in the oscillatory and synchronized character is sufficient for the activities to give rise to visual awareness. We argue that in rodents and lower vertebrates, normal visual awareness is partly due to synchronized oscillatory activities in the optic tectum and partly due to similar activities in visual cortex. It is only in carnivores and primates that visual awareness is wholly due to cortical activities. Based on von Baerian recapitulation theory, we propose that, even in humans, there is a period in early infancy when visual awareness is partially due to activities in the superior colliculus, but that this awareness gradually disappears as the nigrotectal projection matures.     

Color affects perceived odor intensity

In Experiment 1, some odorous solutions (e.g., strawberry) were rated as smelling stronger when colored (e.g., red) than when colorless. Experiment 2 showed this effect to be due to a perceptual change rather than a response to experimental demand characteristics. Experiment 3 showed that the color-induced increase in odor intensity is not due to subjects' preexperimental experience with particular color-odor combinations, because the increase occurred with novel ones. We conclude that color induces a weak olfactory percept that combines with odorant-induced percepts. The effect may be due to conditioning or may be the result of residual intersensory neural connections left over from infancy.     

Intrusion errors in visuospatial working memory performance

This study tested the hypothesis that failure in active visuospatial working memory tasks involves a difficulty in avoiding intrusions due to information that is already activated. Two experiments are described, in which participants were required to process several series of locations on a 4 × 4 matrix and then to produce only the final location of each series. Results revealed a higher number of errors due to already activated locations (intrusions) compared with errors due to new locations (inventions). Moreover, when participants were required to pay extra attention to some irrelevant (non-final) locations by tapping on the table, intrusion errors increased. Results are discussed in terms of current models of working memory functioning.     

What procedural due process means to a school psychologist: A dialogue

Courts and the Congress have recently extended to school children safeguards encompassed by procedural due process in cases involving disciplinary suspensions and special education placements. The meaning of due process and its implications for psychologists are illustrated in a hypothetical dialogue between a constitutional lawyer and a school psychologist.     

The Relationship of Sex, Sex Role, and Mental Health

Mental health differences due to sex, sex-role identification, and sex-role attitudes were investigated using 109 undergraduate students. Females reported higher levels of depression and anxiety. Both males and females with more liberal scores on the Attitudes Toward Women Scale scored higher on the Well-Being Scale of the California Psychological Inventory. No differences due to androgyny were found.     

Age and type of crossed aphasia in dextrals due to stroke

Thirty-nine cases (37 from the literature and 2 personal) of crossed aphasia in dextrals due to stroke were reviewed concerning age, sex, and type of aphasia. Results showed that Broca's aphasics are younger than the remaining group, males predominate, and several types of aphasia have been described similarly to the aphasias due to left-hemisphere lesions in dextrals.     

Correlational cuing as a function of target complexity and target-flanker similarity

It is generally assumed that the correlational cuing effect (CE) between targets and correlated flankers is due to learning association between the flankers and their correlated responses. The present study challenges this view. Experiment 1 shows that the CE for targets composed of color is eliminated as soon as the correlation is removed. Experiment 2 shows that the CE during training is not due to association of the flankers with responses. Experiment 3 shows that at least some of the CE during training with the correlation is due to repetition priming of the display. Experiment 4 replicates the results of Experiment 1 for orientation targets. In Experiments 5-7, more typical tasks with letter targets are examined, and it is demonstrated that preexperimental similarity between targets and correlated flankers is crucial. The CE for correlated but dissimilar target-flanker pairs, similar to that for color and orientation targets, is confined to on-line processes that occur during training. The CE is transferred, however, for correlated and similar target-flanker pairs. We propose that, at least for the simple stimulus to response mapping used in our study, the CE is not due to learning at all. Instead it is due to (1) on-line processes, such as repetition priming, that occur during training with the correlation and (2) a regular flanker effect (see, e.g., B. A. Eriksen & C. W. Eriksen, 1974) that occurs for similar target-flanker pairs.     

Home Sweet Home! Does Moving Have (Lasting) Effects on Housing Satisfaction?

Previous research has found that moving has lasting effects on housing satisfaction while adaptation to changing living environments is surprisingly absent from this research. This paper challenges and extends this current state of research. Using data from a large-scale German household panel we find that housing satisfaction (a) sharply declines before the move (self-selection into relocation), (b) substantially increases after moving (relocation effect), (c) declines in the following years (adaptation), (d) after about 2 years reaches satisfaction levels similar to the levels several years before the move (full adaptation), (e) but due to selection into moving stays above satisfaction levels in the years directly before the move (lasting gains due to self-selection). Further analyses indicate that moving due to house-related reasons leads to partly lasting gains, while moving due to significant life events only has temporary effects. Finally, we show that permanent changes in housing satisfaction due to house-related relocations can be fully explained using self-assessed comparisons between old and new living environment.     

Pathomechanisms of cervical headaches

Various types of disorders of the cervical region may produce headache. In many of these increased tension of the neck musculature plays an important role. The following mechanisms underlying headache are described and differentiated: 1. Headache due to faulty muscle pattern (stereotype) resulting in overstrain of the upper fixators of the shoulder girdle (upper part of the m.trapezius and levator scapulae); faulty respiration with the aid of the upper auxillary muscles even at rest is pointed out. 2. A forward drawn head position producing static overstrain in the posterior neck muscles and compensatory retroflexion of the cranio-cervical junction resulting in blockage in this region. 3. Anteflexion and ligament pain mainly due to faulty position at work and jolting. 4. Static disturbance in the frontal plain due to obliquity producing asymmetrical strain in the neck musculature. 5. Increased muscular tension due to psychological stress. 6. Blockage in the regions of the cervical spine, shoulder girdle and upper ribs with reflex muscular spasm. 7. Reflex spasm of the neck musculature in visceral disorders causing in addition blockage of the cervico-thoracic junction (heart, gall bladder). 8. Pain arising from the posterior arch of the atlas (here described for the first time). 9. Headache due to vertebral artery involvement. The type of headache seems to be determined rather by the individual mode of reaction than by the mechanism underlying it. As a rule a combination of mechanisms is actually found.