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N400 and Lyrics Processing

Besson et al. (1998) studied the relationship between song lyrics and tune processing

with the ERP technique to see whether the two kinds of processing were separated or

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integrated. They used 200 brief excerpts of best known French operatic songs and

manipulated the word at lyric-final position to be semantically anomalous, harmonic

anomalous (i.e. words sung out of key) or both. Hence, four experimental conditions were

constructed: semantically congruous and sung in key, semantically incongruous and sung in

key, semantically congruous and sung out of key and semantically incongruous and sung out

of key. They asked subjects, who were all musicians, to attend to the stimuli and to detect

semantic and harmonic incongruities. By recording subjects’ ERPs, they found a widespread

N400 effect elicited by semantic anomalies and a parietal distributed P300 effect by harmonic

anomalies. As for the condition with semantically incongruous and sung out of key, both

N400 and P300 were observed, though with smaller amplitude compared to the conditions

with either one type of anomaly. This finding indicated two significances. First, lyrics

processing would elicit N400 in the same manner as speech processing, suggesting that the

meaning of lyrics were not affected by the musical structures imposed on it. Second, with

different components elicited, lyrics and tunes processing were considered to be independent

of each other.

In an extended behavioral study, Bonnel et al. (2001) investigated the same issue but

with different methodology. Using the same corpus of French operatic song materials, they

designed two tasks, a single task and a dual task, which also involved four conditions: correct

version, semantic anomaly, tune anomaly and both types of anomalies. In the single task,

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subjects were divided into two groups and required to detect the anomaly in either language

or music condition. While in the dual task, all subjects needed to pay attention to both

language and music dimensions as to judge whether there is anomaly of each type. With this

methodology, the researchers could see how subjects’ attention was affected and distributed

in the single task and dual task. According to the results, lyrics and tunes were considered to

be processed independently since no deficit in subjects’ performance was observed in the dual

task. In other words, subjects were able to divide their attention to lyrics and tunes and to

perceive the two dimensions separately. Also, by recruiting singers, instrumentalists and

non-musicians as subjects and later comparing these groups’ performance, the musical

expertise was found independent of the authors’ findings. Thus, despite that ERPs were not

employed as measurement in this study, the behavioral results supported Besson et al’s (1998)

finding that showed the independence of lyrics processing.

Another study examining the processing of tunes and lyrics was carried out by Gordon

and her colleagues (Gordon et al., 2010). Taking a different position, they argued that sung

words (i.e. lyrics) were processed interactively with melodies in songs. Employing a

prime-target word pair paradigm, they designed four experimental conditions based on

same-different task with tri-syllable French words: same word-same melody, same

word-different melody, different word-same melody and different word-different melody.

Similarly, subjects, who were non-musicians, were instructed to decide whether the pairs of

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words or melodies were the same by performing either the linguistic or the musical task. As

expected, larger N400 was found when the prime and target words were different. To their

surprise, a similar N400 effect was also observed when melodies were different in

prime-target pair, which had similar onset latency but was smaller in amplitude compared to a

classical pattern of N400. In addition, the N400 found in the musical task was followed by a

late positivity. Topographically, the N400 effect was larger over centro-parietal sites in

linguistic task and larger over parietal sites in musical task, and it showed a slightly larger

right hemisphere predominance in both tasks. On interpreting the N400 effect found in the

musical task, Gordon et al. (2010) attributed it to the automatic processing of sung word

meaning regardless of the direction of attention. With the elicitation of N400 effect in musical

task, it was thus asserted that there was an interaction between lyrics and melody processing.

This finding, though in contrast to previous studies (Besson et al., 1998; Bonnel et al., 2001),

still could be taken as one more piece of evidence supporting the similarity in the processing

of spoken language and lyrics.

To briefly sum up, all the three studies illustrated above discussed the issue of lyrics

processing. Even though they reached different conclusions in terms of the relationship

between lyrics processing and tune processing, their results all suggested that lyrics were

processed as speech that would elicit N400 when semantic anomaly or semantic

unexpectancy appeared. However, the paradigms used in these studies might be a

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confounding factor in addressing lyrics processing because they all directed subjects’

attention to one specific task (e.g. linguistic or musical task), which might have had subjects

intentionally attend to the semantic meaning of lyrics when performing the task. Therefore,

the observed semantic processing of lyrics might be task-specific, and whether people

semantically process lyrics in regular song perception is still unknown. What’s more, the

manner of lyrics stimuli presentation in the studies is to have the songs sung a cappella (i.e.

without musical instruments accompanied). Though the way of presentation enables listeners

to recognize that the auditory stimuli are songs, it is not as “authentic” as how people

generally perceive lyrics when listening to songs.

Regarding the two possible confounding factors (i.e. paradigm and stimulus presentation)

in these studies on lyrics processing, the current study therefore carried out a different

experimental design by employing a semantic priming paradigm and presenting lyrics

naturally as excerpts of songs, as will be discussed in Chapter 3.

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