The International Affective Picture System (IAPS) (Lang, Ohman, & Vaitl, 1988) is a standardized set of photographs to induce emotions in the context of experimental investigations. The aim of this study was determine the psychometric behavior of the IAPS for the preparation of standards in the Chilean population and the subsequent validation of the instrument for its use in Chile. 208 university students participated (40% men) and had an affective experience induced using the presentation of visual stimuli extracted from sets 7 and 14 of the IAPS. In order to evaluate valence, arousal and dominance, the self-assessment manikin (SAM) was used, made up of pictographic scales for each dimension and a scale of continuous variation of emotional reactions. The IAPS showed psychometric behavior comparable to the original, with the same boomerang-shaped distribution of scores being found in the valence/arousal relationship. The IAPS is a reliable tool for inducing emotions in studies related to affectivity.

It is well established that acute stress produces negative effects on high level cognitive functions. However, these effects could be due to the physiological components of the stress response (among which cortisol secretion is prominent), to its psychological concomitants (the thoughts generated by the stressor) or to any combination of those. Our study shows for the first time that the typical cortisol response to stress is sufficient to impair metacognition, that is the ability to monitor one’s own performance in a task. In a pharmacological protocol, we administered either 20 mg hydrocortisone or placebo to 46 male participants, and measured their subjective perception of stress, their performance in a perceptual task, and their metacognitive ability. We found that hydrocortisone selectively impaired metacognitive ability, without affecting task performance or creating a subjective state of stress. In other words, the single physiological response of stress produces a net effect on metacognition. These results inform our basic understanding of the physiological bases of metacognition. They are also relevant for applied or clinical research about situations involving stress, anxiety, depression, or simply cortisol use.

The revised restraint scale (RS) it's a psychometric instrument for measuring chronic alimentary restraint. Aim: To obtain reliability measures and factorial structure of a Spanish RS version. Subjects and methods: 640 female undergraduate students completed the instrument. An exploratory factorial analysis (Le. principal components, with an oblique rotation-oblimin-) was performed over the RS scores. Results: Both RS sub-scales shown appropriate reliability levels, while KMO (0,89) and Barret (x²=1762,22; p< 0,01) test were acceptable. After exploratory factorial analysis two correlated factors (diet concern and weight fluctuations) emerged, explaining 51 ¿5% of the variance. Conclusions: The Spanish RS version has a factorial structure congruent with the original self-report.