The perception of surface curvature from optical motion

Observers viewed the optical flow field of a rotating quadric surface patch and were required to match its perceived structure by adjusting the shape of a stereoscopically presented surface. In Experiment 1, the flow fields included rigid object rotations and constant flow fields with patterns of image acceleration that had no possible rigid interpretation. In performing their matches, observers had independent control of two parameters that determined the surface shape. One of these, called the shape characteristic, is defined as the ratio of the two principle curvatures and is independent of object size. The other, called curvedness, is defined as the sum of the squared principle curvatures and depends on the size of the object. Adjustments of shape characteristic were almost perfectly accurate for both motion conditions. Adjustments of curvedness, on the other hand, were systematically overestimated and were not highly correlated with the simulated curvedness of the depicted surface patch. In Experiment 2, the same flow fields were masked with a global pattern of curl, divergence, or shear, which disrupted the first-order spatial derivatives of the image velocity field, while leaving the second-order spatial derivatives invariant. The addition of these masks had only negligible effects on observers’ performance. These findings suggest that observers’ judgments of three-dimensional surface shape from motion are primarily determined by the second-order spatial derivatives of the instantaneous field of image displacements.     

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.

     

The retinal threshold gradient in the presence of a high-luminance target and in total darkness

The retinal threshold was measured along the horizontal meridian for the dark-adapted eye and for the same retinal region light-adapted by stray light from a small foveally fixated high-luminance target. This was done to quantify the irradiation phenomenon in the foveal-parafoveal boundary region. Two target luminances were investigated (5,531 and 13,000 fL). Seven Ss made threshold settings using a variable-intensity test spot whose retinal image was located at various angular separations from the foveal center as far as 10 deg in the temporal field. Threshold slopes were steeper for test spots imaged from 15min to 1 deg of arc from the foveal center than for spots imaged from ldegl5min to 10 deg of arc from the foveal center for the illuminated target conditions. The angular distance between the fovea and the intersection of the steep component with the shallow component of each threshold curve tended to shift toward the target’s edge with an increase in target luminance. These data are interpreted as an indication that a dynamic neural mechanism is involved in producing the irradiation phenomenon.     

Cultural aspects of mental health and mental health service delivery with a focus on Nigeria within a global community

With an endless range of subgroups and individual variations, culture bears upon what all people bring to the clinical setting. Culture could account for health-seeking behaviour, type of services and support system and variations in how people communicate their health concerns. Culture may underlie presentation of sets of symptoms that are peculiar to certain societies – culture-bound syndromes. Culture also influences the meanings that people impart to their illness and also stigma associated with such illnesses. Culture must be viewed from the patients, clinicians and health system dimensions. Changes in mental health service delivery in last few decades have yielded culturally competent mental health services. The aim of this paper was to discuss culture and mental health with a focus on Nigeria and from a global perspective.     

Validation of a Brief Version of the Difficulties in Emotion Regulation Scale (DERS-18) in Five Samples

The field of affective clinical science has expanded dramatically over the past several decades (Rottenberg and Gross 2003; Tracy et al. 2014). An important part of this research is understanding emotion regulation and dysregulation, in particular, how individuals differ in their ability to identify, accept, and manage their emotional experiences. One of the most common and widely cited measures of emotion dysregulation is the Difficulties with Emotion Regulation Scale (DERS; Gratz and Roemer 2004), which has been extensively used to facilitate understanding of how emotion dysregulation is associated with psychiatric symptoms, other emotion-related constructs, and treatment progress. While this scale has contributed greatly to our understanding of emotion regulation problems, its length makes its inclusion in brief study protocols difficult, limiting its utility and increasing participant burden. In order to address this issue, we developed a short form version of the DERS (DERS-18) composed of the strongest items from each of the measure’s six subscales from the original DERS publication (Gratz and Roemer 2004), and then validated this measure in five datasets that vary in age and sample type. Our results demonstrate that an 18-item short-form of the DERS exhibits a similar structure as the original 36-item DERS, demonstrates excellent reliability and validity, and performs similarly to the original DERS despite comprising half the items. The DERS-18 has the potential to improve and expand emotion regulation assessment while reducing demands on research participants.     

Schwierigkeiten in der psychotherapeutischen Arbeit

Dealing with difficult clients, situations and their own emotions is an integral part of psychotherapists’ daily work; however, what is the nature of difficulties in psychotherapy and how should therapists’ deal with them? In spite of the high relevance of these topics for therapeutic practice, scientific research in this area lacks consistent definitions of difficulties and the respective coping strategies. This article summarizes the development of current research approaches and respective results.