The phonatory system (phonation process) includes the larynx and all sub-laryngeal and laryngeal structures. This system determines the characteristics of the source signal (F0 contour; 75–300 Hz for men, 100–500 Hz for women). Finally, the filter system (resonance and articulation processes) includes all the air cavities between the larynx and the opening of the mouth and nostrils (vocal tract) and determines the energy distribution of the sound (frequency spectrum characteristics and formant DNA Damage inhibitor contour). The structure of vocalizations therefore depends on the anatomy and physiology of each of these systems. The mechanism

of vocal production is similar in humans and other mammals. However, in humans, the particular position of the larynx that rests low in the throat and is also mobile, gives us a long and flexible pharyngeal cavity and a nearly

90° connection between the pharyngeal and oral cavities. Consequently, we benefit from important articulatory possibilities. We are selleck antibody inhibitor able to modify the size of our oral and pharyngeal cavity using our tongue, lips, teeth, hard and soft palate, and jaw. This ability plays a crucial role in human speech. For example, by constricting the vocal tract in different places, we can create various patterns of change in the first two formants (F1, around 500 Hz; F2, around 1500 Hz), thus producing different vowels. Higher formants (e.g. F3, around 2500 Hz) are fairly constant and depend on the vocal tract length (Fant, 1960). These morphological particularities associated with an important motor control are at the basis of the

evolution of speech (Fitch, 2000a; Jürgens, 2009). Three types of research paradigms have been used to study medchemexpress affective prosody in humans: natural vocal expression, induced emotional expression and simulated emotional expression (Murray & Arnott, 1993; Scherer, 2003; Juslin & Scherer, 2005). The first approach consists of analysing voices recorded in naturally occurring emotional situations and is of high ‘ecological validity’ (i.e. high accuracy of the underlying speaker state; e.g. Williams & Stevens, 1972; Roessler & Lester, 1976; Frolov et al., 1999). The second approach is based on artificially induced emotions in the laboratory, using psychoactive drugs, presentation of emotion-inducing films or images, or recall of emotional experiences (e.g. Scherer et al., 1985; Tolkmitt & Scherer, 1986; Zei Pollermann & Archinard, 2002). The third and most often used approach consists of analysing simulated emotional expression, produced by actors asked to pronounce a word or sentence by expressing particular emotional states (e.g. van Bezooijen, 1984; Banse & Scherer, 1996; Hammerschmidt & Jürgens, 2007). Vocal cues to emotions are emitted involuntarily.