The Role of Auditory Feedback in Speech and Song Tim A. Pruitt and Peter Q. Pfordresher University at Buffalo, State University of New York When singing a melody or producing sentences, we take for granted the fact that the sounds we create (auditory feedback) match the intended consequences of our actions. The importance of these perception/ action matches to production is illustrated by the detrimental effects of altered auditory feedback (AAF). Previous research in the domain of music has shown that when AAF leads to asynchronies between perception and action, timing of production is disrupted but accuracy of sequencing is not. On the other hand, AAF manipulations of pitch disrupt sequencing but not timing. Such dissociative effects, as well as other findings, suggest that sensitivity to AAF may be based on hierarchical organization of sequences. In the current research we examined whether similar effects are found for the production of speech, for which syllables rather than pitches may constitute content units. In the first experiment, participants either sang melodies or spoke sequences of nonsense syllables. In the second experiment, the tasks were combined such that participants sang syllable sequences. Production in both experiments was accom- panied by either normal, asynchronous, or content altered auditory feedback. Across experiments, effects of AAF on the accuracy of sequencing were similar in speaking and singing tasks, and in all cases reflected the dissociative effects described earlier. For timing of production, however, previous results were only found when participants sang sequences that did not have varying syllabic content. These results suggest that sensitivity to timing exists at multiple hierarchical levels, particularly at the syllable and phonetic levels. Keywords: auditory feedback, sequencing, timing, music and language Anecdotes from drive-thru workers, cellular phone users, and online video game players tell of communication difficulties due to signal delays between speaking and hearing their own voice. This postponement in hearing self-produced auditory information re- sults in speech disfluencies such as stuttering and repeating words. The novelty mobile phone application Speech Jammer (Hou, 2014) operates similarly by allowing users to implement a delay between the input to the device’s microphone and its audio output. Speech Jammer has gained popularity on the Internet as users have posted YouTube videos documenting production disturbances during their attempts to read selections, give consumer reviews, or per- form songs. Likewise, the speech jammer gun (Kurihara & Tsu- kada, 2012) technologically elaborates on this principle to create practical applications for crowd control or maintaining silent en- vironments by disrupting speech without physically distressing its targets. All of the earlier cases illustrate that even the slightest desyn- chronization between producing and subsequently hearing audi- tory information can have profound effects on speech. But given the lack of control in such real-world examples it is difficult to pinpoint the origin of this disruption. One possibility involves feedback synchrony, which refers to whether the onsets and offsets of speech sounds line up in time with each other. Asynchronies between actions (spoken syllables) and auditory feedback have been the focus of accounts for such disruptive effects. However, another possibility emerges from cases in which the resulting content of auditory feedback has been altered such that the cate- gorical event (a syllable) of feedback does not match the intended event. If, for instance, a feedback delay is as long as a spoken syllable, then the speaker would hear the previous syllable when generating the current syllable and any resulting disruption would reflect a deviation in content rather than asynchronous timing. The distinction between feedback content and timing is critical here because it bears on the nature of mapping between perception and action. Previous research in the domain of music, reviewed in the following, has suggested that these alterations have distinct effects on production thus suggesting that perception and action associations are constrained by the temporal hierarchy used to represent the structure of a sequence. However, no research to date has addressed whether comparable effects may occur for speech, thus leaving open the question of whether perception/action asso- ciation in speech relate to those of music. In light of this, we report on two experiments that address critical questions involving how sensory information relates to motor information. First, do people use feedback to guide speech in the same way that they use feedback to produce melodies? This question reflects a critical debate in the current literature regarding representations used to process music versus language (e.g., Patel, 2008). Second (and related), to what degree is the use of feedback This article was published Online First November 10, 2014. Tim A. Pruitt and Peter Q. Pfordresher, University at Buffalo, State University of New York. This research was supported in part by NSF Grants BCS– 0642592 and BCS–1256964. We are grateful to Anastasiya Kobrina and Esther Song for assistance with data collection, and to Pauline Larrouy-Maestri, James Mantell, Kathleen Jocoy, Ken Steele, James Sawusch, and Eduardo Mer- cado III for helpful comments on an earlier version of this paper. Correspondence concerning this article should be addressed to Tim A. Pruitt or Peter Q. Pfordresher, Department of Psychology, 204 Park Hall, University at Buffalo, State University of New York, Buffalo, NY 14260. E-mail: tapruitt@buffalo.edu or pqp@buffalo.edu This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly. Journal of Experimental Psychology: Human Perception and Performance © 2014 American Psychological Association 2015, Vol. 41, No. 1, 152–166 0096-1523/15/$12.00 http://dx.doi.org/10.1037/a0038285 152