Consecuencias de las manchas

Humans can perceive emotion not only from facial expressions but also from voices (Ethofer, Pourtois, & Wildgruber, 2006a). Researchers have used behavioural, neuroanatomical, electrophysiological, and neuroimaging methods to investigate audiovisual integration of emotional signals and explore the effects of auditory information in the recognition of facial expressions.

de Gelder and Vroomen (2000) explored the combination of information from facial expressions and tones of voices in the recognition of emotion. In one of their experiments, happy and sad facial expressions and voices were adopted. Participants were presented with face-voice compounds (either emotionally congruent or incongruent), and were asked to judge whether the face was happy or sad, ignoring the tones of voices. The results showed that reaction times were slower in the incongruent compounds than in the congruent compounds, suggesting the incongruent voices impair the recognition of facial expressions. The results were replicated by another study (Dolan et al., 2001). In this study, Dolan et al. (2001) used event-related functional Magnetic Resonance Imaging (fMRI) to examine how the presentation of voices influences the recognition of facial expressions. The experiments used a computer-morphing procedure to create fearful facial expressions of level of 50% physical intensity and happy facial expressions of level of 50% physical intensity. The face-voice compounds consisted of the morphed emotional faces (fearful or happy)

and neutral sentences with a fearful tone or a happy tone. Participants were asked to categorise the facial expressions as either fearful or happy as quickly and accurately as possible. Behavioural data indicated that reaction times of the congruent face-voice stimuli were faster than those of the incongruent ones. Moreover, the greater activation of left amygdala was found for the congruent face-voice stimuli than for the incongruent ones. Further analyses showed that the activation of amygdala was mainly elicited by fearful congruent pairs. Besides the amygdala, the fearful face-fearful tone stimuli elicited an activation of right fusiform cortex, compared to fearful face-happy tone.

The results were replicated by a study performed by Ethofer et al. (2006b), in which participants were asked to rate the valence of emotional faces on a nine-point self-assessment manikin scale (SAM), while ignoring concurrently presented voices. The blood oxygenation level-dependent (BOLD) responses in the right fusiform gyrus were enhanced when participants rated fearful faces simultaneously presented with congruent fearful tones, in contrast with when participants rated the same fearful faces with incongruent happy tones. Another fMRI study (Kreifelts, Ethofer, Grodd, Erb, & Wildgruber, 2007) investigating on the audiovisual integration of emotional signals in voices and faces revealed that the bilateral pSTG and right thalamus were more strongly activated by the audiovisual stimuli than the unimodal stimuli.

In a recent neuroimaging study, Müller et al. (2011) explored the influence of emotional sounds on facial expressions perception and neural structures using audiovisual

congruent and incongruent stimuli. Due to the fact that no context effects were found for prototypical fearful and happy facial expressions in their pre-study, the degraded happy or fearful faces were created by merging the prototypical fearful or happy facial expressions with the neutral mouths of the same actors. The face-voice stimuli were comprised of faces (either displaying happy, neutral, or fearful) and auditory stimuli. The auditory stimuli were either yawn (neutral) or emotional sounds like laugh (happy) or scream (fearful). Participants were instructed to ignore the sounds and to rate the presented facial expressions on an eight-point rating scale from extremely fearful to extremely happy. The results revealed that degraded fearful facial expressions were rated as being more fearful when accompanied by screams compared to yawns or laughs. There were no context effects found for degraded happy facial expressions. These results were consistent with the results of Ethofer et al. (2006b) who also found context effects for fearful but not for happy faces. Happy facial expressions were recognised more accurately and faster than any other facial expressions (Ekman, Friesen, & Ellsworth, 1982; Gur et al., 2002; Kirita & Endo, 1995; Montagne, Kessels, de Haan, & Perrett, 2007). This happy face advantage might be the reason that there were no context effects on the recognition of happy facial expressions. Moreover, the imaging data showed that incongruence between emotional faces and sounds evoked greater activation in the middle cingulate cortex, right superior frontal cortex, right supplementary motor area as well as the right temporoparietal junction. Taken together, the empirical data from these mentioned audiovisual studies revealed better recognition performance and larger activations for congruent face-sound stimuli,

suggesting that concurrently presented voice plays an important role in the recognition of facial expressions.

In sum, the above-mentioned studies have found that emotional context information has an impact on the recognition of facial expressions. However, there is no consistent pattern of the contextual effects. For example, de Gelder and Vroomen (2000) found that happy facial expressions were recognised more accurately and faster for the congruent pairs than for the incongruent pairs, whereas these effects were not found in other studies (Ethofer et al., 2006b; Müller et al., 2011). The different patterns were observed for the context effects on the recognition of other facial expressions. The inconsistent pattern of context effects might be explained by emotion seed view (Aviezer et al., 2008a, 2008b), which will be discussed in detail in the following section.