Can we hear it and does it matter?: examining the relationship between attention, music perception, and emotional responses to auditory stimuli

Music is an inherently emotional feat of human creativity. Previous studies of music perception have followed the path of speech perception research, in which subjects were asked to simultaneously attend to multiple signals in an effort to determine how much information one could consciously perceive. While these studies have led to the development of models that seek to explain the role of attention in music perception, they lack external validity. Many of these studies have required subjects to detect errors in simultaneously played melodies. While this presents certain demands on attention, it does not accurately portray the way that music is listened to. Music is born out of a burst of emotion and inspiration, and is designed to stir such feelings in those who listen to it. Therefore, the present study sought to study music perception in a more naturalistic setting. In Experiments 1 and 2, participants listened to pieces of music. Participants in Experiment 1 were asked to detect changes in musical arrangement, while participants in Experiment 2 were asked to rate their enjoyment of the music. The results of the present study revealed that participants struggled to identify changes in musical arrangement. Changes that were more noticeable received a significantly greater mean number of emotional responses than changes that were less noticeable, which suggests they had a stronger impact on emotional responses. Further research is needed to determine whether existing models of music perception can be applied to more naturalistic tasks like those used in the present study. CAN WE HEAR IT AND DOES IT MATTER? 3 Can We Hear It and Does It Matter? : Examining the Relationship Between Attention, Music Perception, and Emotional Responses to Auditory Stimuli When we listen to music, how many elements are we consciously aware of? More importantly, does this perception have any impact on our enjoyment of the music itself? Previous research on attention and auditory perception has found that attention is a limited quantity that can be selectively deployed. When Cherry (1953) presented subjects with two recordings of speech that were simultaneously played to the left and right ears (known as dichotomous listening), he found that subjects could selectively deploy their attention to one of the two signals and accurately repeat back the information that was contained on the recording that they were asked to attend to as it was heard. However, this selective attention came at a cost. After the playback of the messages ended, participants were asked to report information from the unattended message. They were unable to identify the topic or any words it contained, and were even unable to accurately determine whether the language was English. Early models suggested that attention functioned like a filter, allowing a person to direct their attention to one signal to enable further processing while the other signal would be lost (Broadbent, 1958). Later research did not support this model, as demonstrated by Treisman (1960) in the well-known “cocktail party” studies where subjects were presented with two recorded messages, one for each ear, which then spontaneously switched to the opposite ear. Without prompting, subjects redirected their attention to the new ear, suggesting that they were attending to both messages on some level. This would suggest that in speech perception different input sources are processed independently, with attention determining the extent to which a source is processed. CAN WE HEAR IT AND DOES IT MATTER? 4 Studying musical perception provides a different challenge for researchers. Many types of music are polyphonic, meaning they contain multiple pitches played at once, as well as multivoiced, meaning they feature more than one sound source (whether that is a voice or an instrument). Given the popularity of polyphonic and multivoiced music over the past five hundred years, it would appear as though humans are able to perceive multiple musical elements as a holistic experience that differs from their perception of speech, where individual inputs are processed independently. Although, the mechanism underlying this ability remains unclear. Researchers have proposed two models to account for the perception of multiple musical inputs. Gregory (1990) found that participants were able to perceive simultaneously played melodies with relative ease and suggested a “divided attention” model where inputs could be processed independently without the losses seen in speech perception. This was in direct opposition to the findings of Kahneman (1973), who utilized a shadowing methodology that was similar to Cherry’s (1953), but instead required participants to shadow songs as opposed to speech. Participants were unable to identify the song they did not shadow, mirroring the results of Cherry (1953). Sloboda and Edworthy (1981) found an effect for key-relatedness on the perception of simultaneously played melodies, where participants were able to detect significantly more errors when the melodies were in the same key. Sloboda and Edworthy suggested that some sort of integration had occurred and proposed a “figure-ground” model where listeners perceive one melody as the focal point and the other melody as the background. According to this model, attention can be directed towards a specific musical element, which becomes the figure or focal point, while the other elements form the background. As listeners direct their attention to different elements, the perceived experience of the music changes. CAN WE HEAR IT AND DOES IT MATTER? 5 Bigand et al. (2000) investigated these models in a study that examined whether participants could detect errors in familiar French nursery rhymes set to music (such as “Gentille alouette”) that were played at the same time. The authors found that while participants were able to detect nearly every melodic error when the nursery rhymes were played individually, performance was halved when the melodies were played simultaneously. There was a significant difference between the performance of musician versus non-musician participants, with musicians detecting more errors in both melodies. Non-musicians detected nearly the same average number of errors as musicians for one of the melodies, but fewer than half for the second. The authors suggested that the non-musician participants selectively deployed their attention to one of the melodies at the expense of the other, in contrast to the prediction of a divided attention model that participants should be able to perceive each melody (and any errors) individually. While musician participants did perform significantly better than non-musician participants, they only detected half of the errors contained within the melodies. The modest performance of these expert participants does not support the divided attention model, which predicts that all inputs are processed independently without the losses seen in speech perception. When the distance between keys of the melodies was increased, there was a significant increase in false alarms for musician participants. Bigand et al. proposed that these expert participants used a perceptual strategy in which they integrated the two signals, which led them to mistakenly believe that the dissonant intervals they perceived were melodic errors. Bigand et al. posited that these participants were not dividing their attention between the two melodies and instead developed an “integration” model for listening to multivoiced music. According to this model, listeners combine various musical elements into one perceptual structure, which enables the interaction of these different elements. This differs from the “figure-ground” model where CAN WE HEAR IT AND DOES IT MATTER? 6 listeners will perceive one melody as the focal point and the other melody as the background. The effect of key distance on false alarms found by Bigand et al. lends support to their integration model. The above studies have focused on the detection of errors in simultaneously played melodies. While this has led researchers to propose different models for how humans perceive multiple musical elements, it does not accurately represent the way that music is normally listened to. Music is inherently emotional, and designed to appeal to the emotions of those who listen to it. As such, it is not sufficient to simply study how attention interacts with the perception of melodic errors without also considering its effect on emotion. Recent studies have examined participants’ emotional reactions to music using continuous ratings and EEG measurements. Mikutta et al. (2012) asked participants to listen to the same piece of music twice. An EEG recording was taken during the first trial, and subjects performed a continuous rating task during the second trial. Mikutta et al. found that music induced changes in participants’ brain functioning in areas that are associated with emotions and arousal. Moderately strong correlations were found between individual subjects’ ratings of emotion and the mean rated emotion of all subjects, and between sound pressure and mean levels of arousal. Markovic et al. (2017) utilized a similar methodology and found that the context in which participants listened to music influenced their brain activity. When participants listened to music passively, they exhibited brain activity that was indicative of being in an emotionally arousing situation, which the authors suggested meant they were immersed in the music. When participants rated their emotional reactions as they listened there was a decrease in that same brain activity, which is often associated with completing long, boring tasks. In another listening study, Trost et al. (2015) CAN WE HEAR IT AND DOES IT MATTER? 7 found that changes in brain activity corresponded to changes in musical features including timbre, rhythm, and energy. I am unaware of previous studies that have examined t