Psychophysiological, behavioral, and cognitive indices of the emotional response: a factor-analytic study

Previous research on the components of the emotional response employing factor analytic studies has yielded a two-factor structure (Lang, Greenwald, Bradley, & Hamm, 1993; Cuthbert, Schupp, Bradley, Birbaumer, & Lang, 2000). However, the startle blink reflex, a widely employed measure of the emotional response, has not been considered to date. We decided to include two parameters of the startle reflex (magnitude and latency) in order to explore further how this response fits into the two-factor model of emotion. We recorded the acoustic startle blink response, skin conductance response, heart rate, free viewing time, and picture valence and arousal ratings of 45 subjects while viewing 54 pictures from the International Affective Picture System (IAPS; 18 unpleasant, 18 neutral, and 18 pleasant). Factorizations of all measures gave a two-factor solution (valence and arousal) that accounted for 70% of the variance. Although some measurements, including heart rate change, did not behave as predicted, our results reinforce the two-dimension model of the emotion, and show that startle fits into the model. Keywords: startle reflex, heart rate, skin conductance, emotional response, orienting response La investigacion previa sobre los componentes de la respuesta emocional empleando estudios de analisis factorial ha proporcionado una estructura de dos factores (Lang, Greenwald, Bradley y Hamm, 1993; Cuthbert, Schupp, Bradley, Birbaumer y Lang, 2000). Sin embargo, el parpadeo reflejo de sobresalto, una medida ampliamente empleada de respuesta emocional, no se ha considerado hasta la fecha. Decidimos incluir dos parametros del reflejo de sobresalto (magnitud y latencia) para explorar si esta respuesta se ajusta al modelo bifactorial de la emocion. Registramos el parpadeo reflejo de sobresalto acustico, la respuesta de conductancia de la piel, la tasa cardiaca, el tiempo de vision, y las evaluaciones de valencia y de arousal de 45 sujetos mientas miraban 54 representaciones del IAPS (18 desagradables, 18 neutrales, y 18 agradables). La factorizacion de todas las medidas proporciono una solucion de dos factores (valencia y arousal) que explicaban el 70% de la varianza. Aunque algunas medidas, incluyendo el cambio en tasa cardiaca, no se comportaban como se habia predicho, nuestros resultados refuerzan el modelo bidimensional de la emocion y demuestran que el sobresalto se ajusta al modelo. Palabras clave: reflejo de sobresalto, tasa cardiaca, conductancia de la piel, re