View combination: a generalization mechanism for visual recognition

We examined whether view combination mechanisms shown to underlie object and scene recognition can integrate visual information across views that have little or no three-dimensional information at either the object or scene level. In three experiments, people learned four “views” of a two dimensional visual array derived from a three-dimensional scene. In Experiments 1 and 2, the stimuli were arrays of colored rectangles that preserved the relative sizes, distances, and angles among objects in the original scene, as well as the original occlusion relations. Participants recognized a novel central view more efficiently than any of the Trained views, which in turn were recognized more efficiently than equidistant novel views. Experiment 2 eliminated presentation frequency as an explanation for this effect. Experiment 3 used colored dots that preserved only identity and relative location information, which resulted in a weaker effect, though still one that was inconsistent with both part-based and normalization accounts of recognition. We argue that, for recognition processes to function so effectively with such minimalist stimuli, view combination must be a very general and fundamental mechanism, potentially enabling both visual recognition and categorization.     

Processing of contour closure by baboons (Papio papio)

This study investigated the Gestalt law of closure in baboons. Using a computer-controlled self-testing procedure, we trained baboons (Papio papio) to discriminate open versus closed shapes presented on a touch screen with a two-alternative forced choice procedure. Ten baboons (OPEN + group) were trained with the open shapes serving as the positive stimulus (S+), and nine others (CLOSE + group) were trained with the closed shape serving as S+. The OPEN + group obtained higher discrimination performance than the CLOSE + group (Exp 1), but its scores declined when new line segments were added to the stimuli (Exp 2) and after smoothing the end points of the open shapes (Exp 3). The CLOSE + group was less affected by the above manipulations of local stimulus dimension, but its performance was disrupted when the collinearity end points was reduced (Exp 3). Use of a visual search task revealed that the search for an open shape among closed distractors was less attention demanding in baboons than the search for a closed shape among open ones (Exp 4). It is concluded that (1) end lines rather than closeness per se are perceptual primitives for the open versus closed discrimination in baboons, and (2) the relative emphasis on local or configural cues when processing contour closure depends on experiential factors in baboons and is thus subject to interindividual variations.     

Contemporary theories of 1/f noise in motor control

1/f noise has been discovered in a number of time series collected in psychological and behavioral experiments. This ubiquitous phenomenon has been ignored for a long time and classical models were not designed for accounting for these long-range correlations. The aim of this paper is to present and discuss contrasted theoretical perspectives on 1/f noise, in order to provide a comprehensive overview of current debates in this domain. In a first part, we propose a formal definition of the phenomenon of 1/f noise, and we present some commonly used methods for measuring long-range correlations in time series. In a second part, we develop a theoretical position that considers 1/f noise as the hallmark of system complexity. From this point of view, 1/f noise emerges from the coordination of the many elements that compose the system. In a third part, we present a theoretical counterpoint suggesting that 1/f noise could emerge from localized sources within the system. In conclusion, we try to draw some lines of reasoning for going beyond the opposition between these two approaches.     

A century of imagery research: reflections on Cheves Perky's contribution to our understanding of mental imagery

We review contemporary scientific research on the relationship between visual perception and visual mental imagery in the context of Cheves Perky's (1910) landmark article on imagery and imagination. This body of research has firmly established a strong connection between the psychology of imagery and perception and has contributed a strong voice to the imagery debate. We then use the concept of embodiment to discuss additional avenues of inquiry at which Perky's work hinted. These include a more thorough examination of the relationship between imagery and emotion, the creative, active aspects of imagery and imagination, and the methods we can bring to bear on understanding imagery and imagination as a human experience.     

How useful are landmarks when learning a route in a virtual environment? Evidence from typical development and Williams syndrome

The ability to learn a route through a virtual environment was assessed in 19 older children and adults with Williams syndrome (WS) and 40 typically developing (TD) children aged 6-9 years. In addition to comparing route-learning ability across groups, we were interested in whether participants show an adult-like differentiation between "useful" and "less useful" landmarks when learning a route and the relative salience of landmark position versus landmark identity. Each virtual environment consisted of a brick wall maze with six junctions. There were 16 landmarks in the maze, half of which were on the correct path and half on incorrect paths. Results showed that both groups could learn each route to criterion (two successful completions of a route without error). During the learning phase, the WS group produced more errors than the TD group and took longer to reach criterion. This was predominantly due to the large number of perseverative errors (i.e., errors that were made at the same choice point on consecutive learning trials) made by the WS group relative to the TD children. We suggest that this reflects a difficulty in inhibiting erroneous responses in WS. During the test phase, the TD group showed stronger recall of landmarks adjacent to junctions (more useful landmarks) than of landmarks along path sections (less useful landmarks) independent of each individual's level of nonverbal ability. This pattern was also evident in the WS group but was related to level of nonverbal maturation; the differentiation between recall of junction and path landmarks increased as nonverbal ability increased across WS participants. Overall, the results demonstrate that individuals with WS can learn a route but that the development of this ability is atypical.     

Approximate entropy normalized measures for analyzing social neurobiological systems

When considering time series data of variables describing agent interactions in social neurobiological systems, measures of regularity can provide a global understanding of such system behaviors. Approximate entropy (ApEn) was introduced as a nonlinear measure to assess the complexity of a system behavior by quantifying the regularity of the generated time series. However, ApEn is not reliable when assessing and comparing the regularity of data series with short or inconsistent lengths, which often occur in studies of social neurobiological systems, particularly in dyadic human movement systems. Here, the authors present two normalized, nonmodified measures of regularity derived from the original ApEn, which are less dependent on time series length. The validity of the suggested measures was tested in well-established series (random and sine) prior to their empirical application, describing the dyadic behavior of athletes in team games. The authors consider one of the ApEn normalized measures to generate the 95th percentile envelopes that can be used to test whether a particular social neurobiological system is highly complex (i.e., generates highly unpredictable time series). Results demonstrated that suggested measures may be considered as valid instruments for measuring and comparing complexity in systems that produce time series with inconsistent lengths.     

‘Coming out’ in therapy? Perceived risks and benefits of self‐disclosure of sexual orientation by gay and lesbian therapists to straight clients

Primary objective: The study's primary objective was to investigate the experiences of gay and lesbian therapists, when considering self‐disclosure of their sexual orientation to straight (i.e. heterosexual) clients. This qualitative study set out to ascertain the key factors gay therapists take into account when considering this decision and to explore the effects this self‐disclosure may have on themselves, their clients and their therapeutic relationships. Research design: The research design was based on the use of semi‐structured interviews, undertaken with a non‐random, purposive sample of counsellors and psychotherapists (n=8) in current practice. The rationale for this method was to aid exploration of therapists' experiences of the process of self‐disclosure. Methods and procedures: Inclusion criteria were for therapists who self‐identified as being gay or lesbian, and who were experienced in clinical work with straight clients. Transcribed data was analysed using inductive thematic analysis. Main outcomes and results: Some therapists reported being confident with self‐disclosure relating to their own sexual orientation. However, a common theme related to the reportedly high levels of anxiety and vulnerability, which therapists identified. Key themes emerged around: respondents' fears of client judgement; a need for therapist self‐protection; self‐awareness of the potential impact of their own fears and prejudices on the therapeutic relationship; and the potential relevance of internalised homophobia, as an overall constraining factor. Conclusions: Self‐disclosure of their sexual orientation to straight clients is constructed, in this initial survey, as being potentially problematic and risky for some gay therapists.     

Life satisfaction and health related quality of life among low-income medical patients: The mediating influence of self-esteem

This study investigated the relationship between life satisfaction, self-esteem, and perceived health for an ethnically diverse, low SES sample of primary care patients. Results indicated that several specific domains of health-related quality of life (HRQL), including health perception, social functioning, mental health, and energy/fatigue, significantly predicted life satisfaction in this sample of 60 patients. Self-esteem mediated this relationship, partially with health perception and fully with the remaining three domains. The results of this study underscore the importance of healthcare interventions that consider the bidirectional relationship between physical and emotional well-being.