Erkin Asutay

Embodied auditory perception: The emotional impact of approaching and receding sound sources.

Research has shown the existence of perceptual and neural bias toward sounds perceived as sources approaching versus receding a listener. It has been suggested that a greater biological salience of approaching auditory sources may account for these effects. In addition, these effects may hold only for those sources critical for our survival. In the present study, we bring support to these hypotheses by quantifying the emotional responses to different sounds with changing intensity patterns. In 2 experiments, participants were exposed to artificial and natural sounds simulating approaching or receding sources. The auditory-induced emotional effect was reflected in the performance of participants in an emotion-related behavioral task, their self-reported emotional experience, and their physiology (electrodermal activity and facial electromyography). The results of this study suggest that approaching unpleasant sound sources evoke more intense emotional responses in listeners than receding ones, whereas such an effect of perceived sound motion does not exist for pleasant or neutral sound sources. The emotional significance attributed to the sound source itself, the loudness of the sound, and loudness change duration seem to be relevant factors in this disparity.

Perception of Loudness Is Influenced by Emotion

Loudness perception is thought to be a modular system that is unaffected by other brain systems. We tested the hypothesis that loudness perception can be influenced by negative affect using a conditioning paradigm, where some auditory stimuli were paired with aversive experiences while others were not. We found that the same auditory stimulus was reported as being louder, more negative and fear-inducing when it was conditioned with an aversive experience, compared to when it was used as a control stimulus. This result provides support for an important role of emotion in auditory perception.

Emotional bias in change deafness in multisource auditory environments

Theories of auditory attention suggest that humans decompose complex auditory input into individual auditory objects, which then compete for attention to dominate auditory perception. Since emotional significance of external stimuli has been argued to provide cues for sensory prioritization and allocation of attention, emotionally salient auditory objects can receive attention to dominate auditory perception. On the basis of the function of audition as an alarm system that informs the organism about its immediate surroundings, and on empirical evidence that emotion can modulate auditory perception, we argue that auditory stimuli with greater emotional saliency would dominate perception in multisource environments. To test our hypothesis, we employed a change detection task in which participants were asked to indicate whether multisource auditory scenes were identical or different. Participants were better at detecting changes at the presence of an emotionally negative environment compared to neutral environment. Further, we found that participants were better at detecting changes of emotionally negative targets compared to neutral targets. Our results demonstrate that detecting changes in auditory scenes is influenced by emotion. The findings are discussed in the light of the theories of auditory attention, emotional modulation of attention, and the adaptive function of emotion for perception.

Attentional and Emotional Prioritization of the Sounds Occurring Outside the Visual Field

The ability to detect and localize sounds in an environment is critical for survival. Localizing sound sources is a computational challenge for the human brain because the auditory cortex seems to lack a topographical space representation. However, attention and task demands can modulate localization performance. Here, we investigated whether the localization performance for sounds occurring directly in front of or behind people could be modulated by emotional salience and sound-source location. We measured auditory-induced emotion by ecological sounds occurring in the frontal or rear perceptual fields, and employed a speeded localization task. The results showed that both localization speed and accuracy were higher, and that stronger negative emotions were induced when sound sources were behind the participants. Our results provide clear behavioral evidence that auditory attention can be influenced by sound-source location. Importantly, we also show that the effect of spatial location on attention is mediated by emotion, which is in line with the argument that emotional information is prioritized in processing. Auditory system functions as an alarm system and is in charge of detecting possible salient events, and alarming for an attention shift. Further, spatial processing in the auditory dorsal pathway has a function of guiding the visual system to a particular location of interest. Thus, an auditory bias toward the space outside the visual field can be useful, so that visual attention could be quickly shifted in case of emotionally significant information.

Negative emotion provides cues for orienting auditory spatial attention.

The auditory stimuli provide information about the objects and events around us. They can also carry biologically significant emotional information (such as unseen dangers and conspecific vocalizations), which provides cues for allocation of attention and mental resources. Here, we investigated whether task-irrelevant auditory emotional information can provide cues for orientation of auditory spatial attention. We employed a covert spatial orienting task: the dot-probe task. In each trial, two task-irrelevant auditory cues were simultaneously presented at two separate locations (left–right or front–back). Environmental sounds were selected to form emotional vs. neutral, emotional vs. emotional, and neutral vs. neutral cue pairs. The participants’ task was to detect the location of an acoustic target that was presented immediately after the task-irrelevant auditory cues. The target was presented at the same location as one of the auditory cues. The results indicated that participants were significantly faster to locate the target when it replaced the negative cue compared to when it replaced the neutral cue. The positive cues did not produce a clear attentional bias. Further, same valence pairs (emotional–emotional or neutral–neutral) did not modulate reaction times due to a lack of spatial attention capture by one cue in the pair. Taken together, the results indicate that negative affect can provide cues for the orientation of spatial attention in the auditory domain.

Auditory attentional selection is biased by reward cues

Auditory attention theories suggest that humans are able to decompose the complex acoustic input into separate auditory streams, which then compete for attentional resources. How this attentional competition is influenced by motivational salience of sounds is, however, not well-understood. Here, we investigated whether a positive motivational value associated with sounds could bias the attentional selection in an auditory detection task. Participants went through a reward-learning period, where correct attentional selection of one stimulus (CS+) lead to higher rewards compared to another stimulus (CS−). We assessed the impact of reward-learning by comparing perceptual sensitivity before and after the learning period, when CS+ and CS− were presented as distractors for a different target. Performance decreased after reward-learning when CS+ was a distractor, while it increased when CS− was a distractor. Thus, the findings show that sounds that were associated with high rewards captures attention involuntarily. Additionally, when successful inhibition of a particular sound (CS−) was associated with high rewards then it became easier to ignore it. The current findings have important implications for the understanding of the organizing principles of auditory perception and provide, for the first time, clear behavioral evidence for reward-dependent attentional learning in the auditory domain in humans.

Affective response predicts risky choice for fast, but not slow, decisions.

We use skin conductance to measure emotional arousal in subjects who make risky choices under time pressure or time delay. Our results show a strong correlation between subjects’ skin conductance responses and their risky choices under time pressure but not under time delay. Subjects were more risk taking for higher levels of measured electrodermal activity (skin conductance). In line with descriptive theories of risky choice, the effect was most pronounced for choices involving losses rather than gains. Taken together, our findings indicate that participants under time pressure rely on affect at the point of decision-making. This provides support for behavioral models that recognize the role of emotional brain systems in decision-making under risk.

Form and content in emotional reactions to sounds

People react emotionally to auditory stimuli. Despite this fact relatively little is known how sounds can create emotional reactions in listeners. We have developed a framework, the Emotion Reaction Model (ERM), that predict that both form features (i.e classical psychophysical attributes such as loudness, sharpness etc) and content feratures (i.e. psychological associations to the sound producing source). Using ERM we tested the relative contribution of form vs. content in producing emotional reactions to sounds. In a first experiment, participants rated their emotional reactions to sounds from qualitatively different categories (animals, humans, machine noise) and to same sounds with time or frequency scrambling applied (thus rendering them difficult to identify, but with retained psychoacoustical properties). Experiments 2 used the same sounds but with a priming procedure and experiment 3 assessed emotional reactions using physiological measures. Overall, content, rather than form, appeared to have the...