From neutral to emotional: The Facial Expression Intensity Test (FExIT)

The Facial Expression Intensity Test (FExIT) measures the level of perceived intensity ofemotional cues in a given facial expression. The test consists of a series of faces takenfrom the NimStim set (Tottenham et al., 2009) whose expressions vary from a neutralexpression to one of the six basic emotions, with ten levels of morphing. The FExIT isvalidated by means of an emotion-related ERP component (i.e., the early posteriornegativity, EPN), which shows a systematic modulation of its amplitude with the level ofexpression intensity. The participant’s task in this test is to identify the expressedemotion among 8 options (i.e. the six basic emotions, a “neutral” and a “I don't know”option). The task is not timed. The score of the FExIT is either the proportion of correctlyidentified emotions, or the proportion of the attribution of an emotion to the facialstimulus (i.e. the attribution of any emotion but not “neutral” or “I don’t know”). Giventhat the facial expression intensity varies continuously from low to high, the FExIT allowsthe determination and comparison of threshold levels for correct responses. The freelyaccessible set of the 700 facial stimuli for the test is divided into two equivalent face lists,which further allows for pretest/posttest experimental designs. The test takesapproximately 25 min to complete and is simple to administer. The FExIT is thus a usefulinstrument for testing different experimental settings and populations.