Large errors in the perception of vertically are generated by luminance borders (integrated across space) not by subjective borders

The rod-and-frame illusion shows large errors in the judgment of visual vertical in the dark if the frame is large and there are no other visible cues (Witkin and Asch, 1948 Journal of Experimental Psychology 38 762-782). Three experiments were performed to investigate other characteristics of the frame critical for generating these large errors. In the first experiment, the illusion produced by an 11 degrees tilted frame made by luminance borders (standard condition) was considerably larger than that produced by a subjective-contour frame. In the second experiment, with a 33 degrees frame tilt, the illusion was in the direction of frame tilt with a luminance-border frame but in the opposite direction in the subjective-contour condition. In the third experiment, to contrast the role of local and global orientation, the sides of the frame were made of short separate luminous segments. The segments could be oriented in the same direction as the frame sides, in the opposite direction, or could be vertical. The orientation of the global frame dominated the illusion while local orientation produced much smaller effects. Overall, to generate a large rod-and-frame illusion in the dark, the tilted frame must have luminance, not subjective, contours. Luminance borders do not need to be continuous: a frame made of sparse segments is also effective. The mechanism responsible for the large orientation illusion is driven by integrators of orientation across large areas, not by figural operators extracting shape orientation in the absence of oriented contours.     

The impact of orbital prefrontal cortex damage on emotional activation to unanticipated and anticipated acoustic startle stimuli

Damage to the orbital prefrontal cortex has been implicated in selectively diminishing electrodermal autonomic nervous system responses to anticipated punishing stimuli (e.g., losing money; Bechara, Damasio, & Damasio, 2000), but not to unanticipated punishing stimuli (e.g., loud noises; Damasio, Tranel, & Damasio, 1990). We extended this research by examining the effects of orbitofrontal damage on emotional responses to unanticipated and anticipated acoustic startles and collecting a more extensive set of physiological measures, emotional facial behavior, and self-reported emotional experience. Consistent with previous research, patients showed intact physiology to an unanticipated startle but failed to show appropriate anticipatory cardiovascular responses (patients’ heart rates decreased, controls’ increased). In addition, patients displayed more surprise facial behavior and reported marginally more fear than did controls in response to the unanticipated startle. Thus, orbitofrontal damage may compromise the ability to anticipate physiologically the onset of aversive stimuli, despite intact or enhanced emotional responses when such stimuli occur unexpectedly.     

Venlafaxine treatment of obsessive-compulsive disorder: case reports

About one-third of patients affected by obsessive-compulsive disorder fail to respond to serotonergic drugs and different strategies have been proposed for these resistant cases. This article reports experiences with venlafaxine in patients with obsessive-compulsive disorder who did not respond or did not tolerate serotonergic drugs.     

Number sense at 12 months predicts 4-year-olds’ maths skills

Preverbal infants spontaneously represent the number of objects in collections. Is this ‘sense of number’ (also referred to as Approximate Number System, ANS) part of the cognitive foundations of mathematical skills? Multiple studies reported a correlation between the ANS and mathematical achievement in children. However, some have suggested that such correlation might be mediated by general-purpose inhibitory skills. We addressed the question using a longitudinal approach: we tested the ANS of 60 12 months old infants and, when they were 4 years old (final N = 40), their symbolic math achievement as well as general intelligence and inhibitory skills. Results showed that the ANS at 12 months is a specific predictor of later maths skills independent from general intelligence or inhibitory skills. The correlation between ANS and maths persists when both abilities are measured at four years. These results confirm that the ANS has an early, specific and longstanding relation with mathematical abilities in childhood.

Research Highlights

• In the literature there is a lively debate about the correlation between the ANS and maths skills.
• We longitudinally tested a sample of 60 preverbal infants at 12 months and rested them at 4 years (final sample of 40 infants).
• The ANS tested at 12 months predicted later symbolic mathematical skills at 4 years, even when controlling for inhibition, general intelligence and perceptual skills.
• The ANS tested at 4 years remained linked with symbolic maths skills, confirming this early and longstanding relation in childhood.

     

Psychosis: New Existential, Systemic, and Cognitive-Behavioral Developments

Until recently, perhaps the major avenues of working with severely disturbed patients have been based upon either organic-chemical or intrapsychic determinants and treatment components. One recent development is an emphasis upon interpsychic and interpersonal factors and determinants in both the understanding and the treatment of extreme psychotic disturbances. Existential, systemic, and cognitive-behavioral conceptualizations and therapies maintain substantial independence of one another. Yet these three share at least two significant commonalities. One is that they each emphasise the interpsychic and interpersonal. A second is this first commonality has led to some exciting new developments in the understanding and treatment of psychosis.     

Orientation sensitivity in the peripheral visual field

Orientation sensitivity in the peripheral visual field has been tested in two tasks: (a) setting horizontal the orientation of a grating at various retinal eccentricities, and (b) matching the orientation of a peripherally viewed grating as close as possible to an oblique reference viewed foveally. Both performances fall off with increasing retinal eccentricity. Magnification of the stimulus optimizes peripheral performance. Peripheral performance, optimized by magnification, varies with retinal eccentricity. It approaches, but does not reach, the foveal value (tested by the same method) at 10 deg of eccentricity, and is much lower at 20 and 30 deg of eccentricity.