The interplay between perceptual organization and categorization in the representation of complex visual patterns by young infants

The relation between perceptual organization and categorization processes in 3- and 4-month-olds was explored. The question was whether an invariant part abstracted during category learning could interfere with Gestalt organizational processes. A 2003 study by Quinn and Schyns had reported that an initial category familiarization experience in which infants were presented with visual patterns consisting of a pacman shape and a complex polygon could interfere with infants' subsequent good continuation-based parsing of a circle from visual patterns consisting of a circle and a complex polygon. However, an alternative noninterference explanation for the results was possible because the pacman had been presented with greater frequency and duration than had the circle. The current study repeated Quinn and Schyns's procedure but provided an equivalent number of familiarization trials and duration of study time for the infants to process the pacman during initial familiarization and the circle during subsequent familiarization. The results replicated the previous findings of Quinn and Schyns. The data are consistent with the interference account and suggest that a cognitive system of adaptable feature creation can take precedence over organizational principles with which a perceptual system comes pre-equipped.     

Reliability and validity of the Spanish Version of the Crisis in Family Systems-Revised

Increasing the representation of Spanish-speaking study participants requires development and dissemination of reliable and valid translated scales. In the urrent study the construct validity was assessed of the Spanish version of the Crisis n Family Systems-Revised, a measure of contemporary life stressors, with a convenience sample of 377 parents interviewed in a study of childhood asthma, although over half of the respondents did not have children with asthma. Most respondents were foreign-born women between 20 to 60 years old (M=35, SD=7). 52% had not completed high school or its equivalent, and 55% reported a household income of dollar 15,000 or less. For a subsample of 25 respondents test-retest reliability was .86 over 2 wk. Reporting more life stressors was associated with greater depressive symptomatology, poorer physical and mental health function, and lower household income. These relationships support the construct validity of the test in Spanish. This study provided strong evidence that this version is a valid and reliable measure of life stressors for a Spanish-speaking population living in the United States.     

Caffeine as a performance-enhancing drug in rats: sex, dose, housing, and task considerations

Past animal studies of the performance-enhancing properties of stimulant drugs, such as caffeine, may have suffered from a number of procedural and ethical problems. For example. the housing condition of the animals was often not taken into consideration. As well, endurance tests, such as the forced swim task, sometimes involved ethically (and procedurally) questionable interference with natural swimming behaviour. Some of the manipulations, such as attaching a weight to the swimming animal's tail to increase the difficulty of the task and using mortality as a dependent variable, seem grotesque, even unnecessary. In this experiment, the performance-enhancing effects of caffeine in a modified forced swim task and a dominance task were evaluated using male and female rats as subjects (N=60), housed in either enriched or isolated environments. Analysis indicated that rats respond to caffeine as an interactive function of sex, housing, dose, and task characteristics. It was concluded that performance-enhancing properties of stimulant drugs may be the result of a complex interplay of variables, making simple generalizations questionable.     

Executive and visuospatial sketchpad resources in euthymic bipolar disorder: Implications for visuospatial working memory architecture

Visuospatial working memory theory is used to interpret the cognitive impairment in euthymic bipolar disorder. Such patients show deficits in the Corsi Blocks Test (CBT) and executive control. To understand these deficits, 20 euthymic bipolar patients and controls were administered the CBT, Visual Patterns Test (VPT), and a new visual memory task designed to make minimal demands on executive resources. Initial analyses validated the visual memory task and implicated executive involvement in the CBT and VPT. Subsequent analyses on a number of tests confirmed CBT and executive deficits while performance was normal on the VPT and visual memory test. ANCOVA indicated that impaired executive function underpinned patients' CBT performance. Implications for the interface between executive and slave systems of working memory are discussed.     

Learning perceptual organization in infancy

It has been demonstrated that older infants (6- to 7-month-olds), but not younger infants (3- to 4-month-olds), use form similarity to organize stimuli consisting of X and O elements. We investigated whether utilization of form similarity is governed by maturation or experience by contrasting how infants perform when familiarized with a single exemplar versus multiple exemplars depicting a particular organization. In Experiment 1, 3- to 4-month-olds failed to organize alternating columns or rows of squares and diamonds or Hs and Is, respectively. In Experiment 2, same-aged infants familiarized with all three patterns (X-O, square-diamond, H-I) displayed evidence of organization. The results suggest that 3- to 4-month-olds can use form similarity to organize visual patterns in a concept-formation task. The findings imply that perceptual organization based on form similarity is learned through experience with multiple patterns depicting a common arrangement, rather than immediately apprehended in an individual pattern.     

Development of form similarity as a Gestalt grouping principle in infancy

Given evidence demonstrating that infants 3 months of age and younger can utilize the Gestalt principle of lightness similarity to group visually presented elements into organized percepts, four experiments using the familiarization/novelty-preference procedure were conducted to determine whether infants can also organize visual pattern information in accord with the Gestalt principle of form similarity. In Experiments 1 and 2, 6- to 7-month-olds, but not 3- to 4-month-olds, presented with generalization and discrimination tasks involving arrays of X and O elements responded as if they organized the elements into columns or rows based on form similarity. Experiments 3 and 4 demonstrated that the failure of the young infants to use form similarity was not due to insufficient processing time or the inability to discriminate between the individual X and O elements. The results suggest that different Gestalt principles may become functional over different time courses of development, and that not all principles are automatically deployed in the manner originally proposed by Gestalt theorists.     

Vagueness as closeness

This paper presents and defends a definition of vagueness, compares it favourably with alternative definitions, and draws out some consequences of accepting this definition for the project of offering a substantive theory of vagueness. The definition is roughly this: a predicate ‘F’ is vague just in case for any objects a and b, if a and b are very close in respects relevant to the possession of F, then ‘Fa’ and ‘Fb’ are very close in respect of truth. The definition is extended to cover vagueness of many-place predicates, of properties and relations, and of objects. Some of the most important advantages of the definition are that it captures the intuitions which motivate the thought that vague predicates are tolerant, without leading to contradiction, and that it yields a clear understanding of the relationships between higher-order vagueness, sorites susceptibility, blurred boundaries, and borderline cases. The most notable consequence of the definition is that the correct theory of vagueness must countenance degrees of truth.     

Preferences Regarding Targeted Education and Risk Assessment in People with a Family History of Major Depressive Disorder

Genetic testing for susceptibility to major depressive disorder (MDD) is not available for clinical use at present. Given this, family history remains the best predictor for development of MDD, and family-history-based risk assessment and information about familial aspects of MDD may be useful to clients at increased risk for MDD attending for genetic counseling. This study uses a mixed-methods design to assess the information needs and preferences of people at increased familial risk for MDD. Telephone interviews were conducted with 23 individuals, who had at least one first-degree relative with MDD and were recruited through advertisements placed on depression education websites. The most preferred way to access depression information was via the internet (87 % of participants), although this preference may have been due to the internet-based recruitment method. The second most preferred dissemination strategy (56 %) was face-to-face delivery through a health professional, including genetic counselors. Individuals reported a need for information about etiology and development of MDD, reproductive decision-making, early detection of symptoms and risk-reducing strategies. Nearly all participants expressed an interest in risk assessment. The present study found evidence of a high level of interest for information targeted to people at increased familial risk for MDD. Genetic counselors are likely to be called upon increasingly to provide supportive counseling to assist clients at increased familial risk in interpreting and contextualizing such information once it becomes available.     

An Occupational Therapy Support Service for University Students With Asperger's Syndrome (AS)

Students with Asperger's Syndrome (AS) face challenges, within third-level education, related to the person, environment, and occupation. This study describes an occupational therapy (OT) service that aims to enhance the interplay between the person (i.e., the student) and his/her occupation within a given context (i.e., college environment). A chart review and Student Satisfaction Survey was used to identify the demographics, concerns, and goals of the students using it. It was found that goals and concerns shift according to students' stage in college and recommends that services employ a student-centered, flexible approach responsive to the particular concerns of these students.     

On the nature of fear of falling in Parkinson's disease

In the elderly, fear of falling (FoF) can lead to activity restriction and affect quality of life (QoL). Our aim was to identify the characteristics of FoF in Parkinson's disease and assess its impact on QoL. We assessed FoF in 130 patients with Parkinson's disease (PD) on scales measuring perceived self-efficacy in performing a range of activities (FES), perceived consequences of falling (CoF), and activity avoidance (SAFFE). A significant difference was found in FoF between PD patients who had previously fallen and those who had not and between frequent and infrequent fallers. Patient-rated disability significantly influenced FoF. Difficulty in rising from a chair, difficulty turning, start hesitation, festination, loss of balance, and shuffling were the specific mobility problems which were associated with greater FoF in PD. Disability was the main predictor of FoF, additionally depression predicted perceived consequences of falling, while anxiety predicted activity avoidance. The FoF measures explained 65% of the variance of QoL in PD, highlighting the clinical importance of FoF. These results have implications for the clinical management of FoF in PD.