Visuo-spatial processing and dimensions of schizotypy: figure-ground segregation as a function of psychotic-like features

The aim of the reported study was to determine whether the ability to segregate a simple figure embedded in a complex visual ground, was associated with psychotic-like features in a sample of undergraduate students. The participants (N =100) were tested on the Hidden Figures Test, as well as the Raven’s Progressive Matrices, and completed a multi-dimensional schizotypy inventory (O–LIFE). The IQ scores were positively related to the number of correct responses on the Hidden Figures Test, but were unrelated to any of the schizotypy measures. Impaired Performance on the Hidden Figures Test was associated with negative schizotypy (‘Introvertive Anhedonia’), and enhanced performance was associated with the ‘Impulsive Non-Conformity’ scale. Performance on the Hidden Figures Test was independent of the positive (‘Unusual Experiences’), and the disorganized (‘Cognitive Disorganization’), schizotypy. The results are discussed in terms of a putative involvement of the frontal lobes in the negative symptomatology of schizophrenia, and in top-down (goal-driven) perceptual processing, as well as the possible compensatory functional aspect of impulsivity in terms of allocating attention

Do Positive Schizotypal Symptoms Predict False Perceptual Experiences in Nonclinical Populations?

We examined whether positive schizotypy (i.e., reports of hallucinatory and delusional-like experiences) in nonclinical participants could predict false perceptual experiences during detection of fast-moving words beyond a possible response bias. The participants (N = 160) were assigned to one of two conditions: they were asked either to make presence/absence judgments (loose criterion) or to read aloud every detected word (strict criterion). Regression analysis showed that high levels of positive schizotypy predicted false alarms in the loose condition and false perceptions of words in the strict condition. The obtained effects were independent of detection accuracy, task order, impulsivity, and social desirability. We discuss the results in the context of information processing biases linked to the positive symptomatology of schizophrenia. Clinical and theoretical implications are also considered

Seeing words that are not there: Detection biases in schizotypy

Objective. The present studies introduced a novel word-detection paradigm to examine detection biases as a function of different schizotypy dimensions in a sample of undergraduate students. Method. The participants (N = 80) were asked to detect fast moving (8 frames/sec) words among simultaneously moving non-words. Results. Positive schizotypy was associated with a tendency to report words that never appeared in the trials. This effect was independent of task order, impulsivity and social desirability. None of the schizotypy measures was associated with correct words (detection accuracy). Conclusions. It is inferred that a bias to report events in the absence of corresponding events may constitute a cross-modal mechanism responsible for translating internally generated experiences into perceptual experiences

Win-stay and win-shift lever-press strategies in an appetitively reinforced task for rats

Two experiments examined acquisition of win-stay, win-shift, lose-stay, and lose-shift rules by which hungry rats could earn food reinforcement. In Experiment 1, two groups of rats were trained in a two-lever operant task that required them to follow either a win-stay/lose-shift or a win-shift/lose-stay contingency. The rates of acquisition of the individual rules within each contingency differed: lose-shift and lose-stay rules were acquired faster than win-stay and win-shift rules. Contrary to a number of previous reports, the win-shift rule was acquired less rapidly than any of the other rules. In Experiment 2, the four rules were taught separately, but subjects still acquired the win-shift rule more slowly than any of the other rules