This study investigated the effects of anxiety on nonverbal aspects of speech using data collected in the framework of a large study of social phobia treatment. The speech of social phobics (N = 71) was recorded during an anxiogenic public speaking task both before and after treatment. The speech samples were analyzed with respect to various acoustic parameters related to pitch, loudness, voice quality, and temporal apsects of speech. The samples were further content-masked by low-pass filtering (which obscures the linguistic content of the speech but preserves nonverbal affective cues) and subjected to listening tests. Results showed that a decrease in experienced state anxiety after treatment was accompanied by corresponding decreases in a) several acoustic parameters (i.e., mean and maximum voice pitch, high-frequency components in the energy spectrum, and proportion of silent pauses), and b) listeners' perceived level of nervousness. Both speakers' self-ratings of state anxiety and listeners' ratings of perceived nervousness were further correlated with similar acoustic parameters. The results complement earlier studies on vocal affect expression which have been conducted on posed, rather than authentic, emotional speech.
The classical Stroop color-naming task was converted to a Web administered version and tested against a conventional computerized version. In the first experiment, 20 male and 20 female participants were tested individually on both Stroop versions in random order. Both versions resulted in strong Stroop effects, but response times were slower overall for the Web-Stroop. A second experiment with 28 participants showed that the test results on the Web-Stroop could be replicated in a less controlled experimental setting, for example in the participant’s own home. In conclusion, findings suggest that administration of the Stroop color-naming test, and response time measurement in milliseconds on a personal computer, is possible via the Internet.
Animal studies indicate that substance P (SP) and its preferred neurokinin-1 (NK1) receptor modulate stress and anxiety-related behavior. Alterations in the SP-NK1 system have also been observed in human anxiety disorders, yet little is known about the relation between this system and individual differences in personality traits associated with anxiety propensity and approach-avoidance behavior, including trait anxiety, neuroticism, and extraversion. Exploring this relation could provide important insights into the neurobiological underpinnings of human anxiety and the etiology of anxiety disorders, as anxious traits are associated with increased susceptibility to develop psychopathological conditions. Here we examined the relationship between central NK1 receptor availability and self-rated measures of trait anxiety, neuroticism, and extraversion. The amygdala was chosen as the primary region of interest since this structure has been suggested to mediate the effect of the SP-NK1 system on anxiety. Anxious traits and NK1 receptor availability, determined with positron emission tomography and the radiotracer [11C]GR205171, were measured in 17 healthy individuals. Voxel-wise analyses showed a significant positive correlation between bilateral amygdala NK1 receptor availability and trait anxiety, and a trend in similar direction was observed for neuroticism. Conversely, extraversion was found to be negatively associated with amygdala NK1 receptor availability. Extraversion also correlated negatively with the NK1 measure in the cuneus/precuneus and fusiform gyrus according to exploratory whole-brain analyses. In conclusion, our findings indicate that amygdala NK1 receptor availability is associated with anxiety-related personality traits in healthy subjects, consistent with a modulatory role for the SP-NK1 system in human anxiety.