The influence of depth segmentation on colour constancy

In real scenes, surfaces in different depth planes often differ in the luminance and chromatic content of their illumination. Scene segmentation is therefore an important issue when considering the compensation of illumination changes in our visual perception (lightness and colour constancy). Chromatic adaptation is an important sensory component of colour constancy and has been shown to be linked to the two-dimensional spatial structure of a scene (Werner, 2003 Vision Research 43 1611 - 1623). Here, the question is posed whether this cooperation also extends to the organisation of a scene in depth. The influence of depth on colour constancy was tested by introducing stereo disparity, whereby the test patch and background were perceived in either the same or one of five different depth planes (1.9-57 min of arc). There were no additional cues to depth such as shadows or specular highlights. For consistent illumination changes, colour constancy was reduced when the test patch and background were separated in depth, indicating a reduction of contextual influences. An interaction was found between the influences of stereo depth and spatial frequency on colour constancy. In the case of an inconsistent illumination change, colour constancy was reduced if the test patch and background were in the same depth plane (2-D condition), but not if they were separated in depth (3-D condition). Furthermore, colour constancy was slightly better in the 3-D inconsistent condition than in the 2-D inconsistent condition. It is concluded that depth segmentation supports colour constancy in scenes with inconsistent illumination changes. Processes of depth segmentation are implemented at an early sensory stage of colour constancy, and they define visual regions within which the effects of illuminant changes are discounted for separately. The results support recent models that posit such implementation of scene segmentation in colour constancy.     

Semantic ambiguity and the failure of inhibition hypothesis as an explanation for reading errors in deep dyslexia

We report evidence for dissociation between explicit and implicit access to word representations in a deep dyslexic patient (JO). JO read aloud a series of ambiguous (e.g., bank) and unambiguous (e.g., food) words and performed a lexical decision task using these same items. When required to explicitly access the items (i.e., naming), JO showed relative impairment for ambiguous compared with unambiguous words. In contrast, the same stimuli produced an advantage for ambiguous words in lexical decision. The results are discussed within a framework of deep dyslexia that considers errors in production to arise through a failure to inhibit spuriously activated candidate representations.     

Dissociating the effects of attention and contingency awareness on evaluative conditioning effects in the visual paradigm

Two experiments are described that investigate the effects of attention in moderating evaluative conditioning (EC) effects in a picture-picture paradigm in which previously discovered experimental artifacts (e.g., Field & Davey, 1999 ) were overcome by counterbalancing conditioned stimuli (CSs) and unconditioned stimuli (USs) across participants. Conditioned responses for individuals who had attention enhanced were compared against a control group and groups for whom attention was impeded using a distracter task. In a second experiment the effects of attention were dissociated from those of contingency awareness by using backward-masked US presentations. The results of these experiments indicate that although associative EC effects may not be disrupted by a lack of contingency awareness, attention is an important factor in establishing conditioning. These results shed some light onto the possible boundary conditions that could explain past inconsistencies in obtaining EC effects in the visual paradigm.     

Deep dyslexia and semantic errors: a test of the failure of inhibition hypothesis using a semantic blocking paradigm

Deep dyslexia is an acquired reading disorder that involves the production of semantic errors and the inability to read aloud nonwords successfully. Several explanations for this reading impairment posit multiple loci of damage to account for the various error types produced in deep dyslexia. In contrast, the failure of inhibition hypothesis suggests that damage in the phonological output lexicon alone can explain these errors. Specifically, this hypothesis proposes normal processing via orthographic and phonological reading routes, as well as an intact semantic system. However, slowed or reduced inhibitory connections result in the failure to suppress spuriously activated neighbours in the phonological output lexicon, where neighbourhood can be defined in terms of phonology, orthography, or semantics. Given a failure to inhibit semantically related candidates, semantic reading errors occur. Important to the test of this hypothesis is that it evolves several predictions that are contrary to performance observed in the normal population. In particular, semantic errors are predicted to be greater in conditions where words are blocked according to semantic category than in random presentations. In addition, a semantic interference effect is expected. The results of semantic blocking were consistent with these predictions and lend support to the failure of inhibition hypothesis.     

Speculation about behavior, brain damage, and self-organization: the other way to herd a cat

This article contrasts aphasic patients' performance of word naming and lexical decision with that of intact college-aged readers. We discuss this contrast within a framework of self-organization; word recognition by aphasic patients is destabilized relative to intact performance. Less stable performance shows itself as an increase in the dispersion of patients' response times compared to college students'. Dispersion is also more pronounced for low-frequency words than for high frequency words. We speculate, that increased dispersion originates in a reduction of constraints that support naming and lexical decision performances. A sufficient reduction of constraints yields qualitative changes in performance such as the production of semantic errors in deep dyslexia. These hypotheses are offered as alternatives to postulating distinct modules.     

Further suicidal behavior among medically serious suicide attempters

Analysis of rates of further suicidal behavior among individuals making medically serious suicide attempts may help to predict suicide and suicide attempt from baseline characteristics of the individual and the index suicide attempt. Data are drawn from a 5-year study of 302 individuals making medically serious suicide attempts with information collected by personal interview at baseline, 6, 18, 30, and 60 months after the index attempt. Within 5 years, 6.7% died by suicide; 37% made at least one nonfatal suicide attempt. Although baseline characteristics permitted a modest prediction of suicide attempt, only a very limited prediction of suicide was possible. Almost half of those who made serious suicide attempts made a further fatal or nonfatal attempt within 5 years. These findings imply the need for enhanced follow-up, treatment, and surveillance of all patients making serious suicide attempts.     

The reported prevalence of mandated community treatment in two Florida samples

Questions on multiple modes of mandated community treatment (e.g. outpatient commitment, advance directive, representative payee, and special housing) were included in two studies of persons with mental illness, using a mail survey of Medicaid enrollees receiving SSI and interviews conducted as part of an evaluation of a specialty mental health court. Results indicate that the majority of individuals reported no experience with any forms of mandated community treatment. However, respondents from the two samples who had been subject to community mandates reported comparatively similar experiences. Additional studies of the prevalence of mandated community treatment are necessary to garner expanded information regarding the use of such mandates. In addition, future studies must assure that the language employed to query individuals regarding such mandates is clearly understood by respondents, as certain terms (e.g. "outpatient commitment") may mean different things to different respondents.     

Recollection, fluency, and the explicit/implicit distinction in artificial grammar learning

In this article, the authors propose that both implicit memory and implicit learning phenomena can be explained by a common set of principles, in particular via participants' strategic use of recollective and fluency heuristics. In a series of experiments, it was demonstrated that manipulating processing fluency had an impact on classification decisions in an artificial grammar learning task (Experiments 1, 2, 4, and 7), showing that participants were using a fluency heuristic. Under identical conditions, however, this manipulation had no effect on recognition decisions (Experiments 3 and 5), consistent with a greater default reliance on recollection. Most significant, the authors also showed that a fluency effect can be induced in recognition (Experiments 4-6) and can be eliminated in classification (Experiment 7).     

Social Anxiety in Children with Anxiety Disorders: Relation with Social and Emotional Functioning

Investigated the psychometric properties of the Social Anxiety Scale for children-Revised (SASC-R) as well as relations between social anxiety and children's social and emotional functioning. Participants were a clinic sample of children, ages 6–11 with anxiety disorders (N = 154) who completed the SASC-R. For a subset of these children, parent ratings of social skills, and self-ratings of perceived competence and peer interactions were also obtained. Factor analysis of the SASC-R supported the original three-factor solution and internal consistencies were in the acceptable range. Among children with simple phobia, scores on the SASC-R differentiated those with and without a comorbid social-based anxiety disorder. Social anxiety was also associated with impairments in social and emotional functioning. Specifically, highly socially anxious children reported low levels of social acceptance and global self-esteem and more negative peer interactions. Girls with high levels of social anxiety were also rated by parents as having poor social skills, particularly in the areas of assertive and responsible social behavior.