Effects of intention in the imitation of sung and spoken pitch.

Pitch content is an important component of song and speech. Previous studies have shown a pronounced advantage for imitation of sung pitch over spoken pitch. However, it is not clear to what extent matching of pitch in production depends on one's intention to imitate pitch. We measured the effects of intention to imitate on matching of produced pitch in both vocal domains. Participants imitated pitch content in speech and song stimuli intentionally ("imitate the pitch") and incidentally ("repeat the words"). Our results suggest that the song advantage exists independently of whether participants explicitly intend to imitate pitch. This result supports the notion that the song advantage reflects pitch salience in the stimulus. On the other hand, participants were more effective at suppressing the imitation of pitch for song than for speech. This second result suggests that it is easier to dissociate phonetic content from pitch in the context of song than in speech. Analyses of individual differences showed that intention to imitate pitch had larger effects for individuals who tended to match pitch overall in production, independent of intentions. Taken together, the results help to illuminate the psychological processes underlying intentional and automatic vocal imitation processes.

Brain responses to altered auditory feedback during musical keyboard production: an fMRI study.

Alterations of auditory feedback during piano performance can be profoundly disruptive. Furthermore, different alterations can yield different types of disruptive effects. Whereas alterations of feedback synchrony disrupt performed timing, alterations of feedback pitch contents can disrupt accuracy. The current research tested whether these behavioral dissociations correlate with differences in brain activity. Twenty pianists performed simple piano keyboard melodies while being scanned in a 3-T magnetic resonance imaging (MRI) scanner. In different conditions they experienced normal auditory feedback, altered auditory feedback (asynchronous delays or altered pitches), or control conditions that excluded movement or sound. Behavioral results replicated past findings. Neuroimaging data suggested that asynchronous delays led to increased activity in Broca's area and its right homologue, whereas disruptive alterations of pitch elevated activations in the cerebellum, area Spt, inferior parietal lobule, and the anterior cingulate cortex. Both disruptive conditions increased activations in the supplementary motor area. These results provide the first evidence of neural responses associated with perception/action mismatch during keyboard production.

Singing with yourself: evidence for an inverse modeling account of poor-pitch singing.

Singing is a ubiquitous and culturally significant activity that humans engage in from an early age. Nevertheless, some individuals - termed poor-pitch singers - are unable to match target pitches within a musical semitone while singing. In the experiments reported here, we tested whether poor-pitch singing deficits would be reduced when individuals imitate recordings of themselves as opposed to recordings of other individuals. This prediction was based on the hypothesis that poor-pitch singers have not developed an abstract "inverse model" of the auditory-vocal system and instead must rely on sensorimotor associations that they have experienced directly, which is true for sequences an individual has already produced. In three experiments, participants, both accurate and poor-pitch singers, were better able to imitate sung recordings of themselves than sung recordings of other singers. However, this self-advantage was enhanced for poor-pitch singers. These effects were not a byproduct of self-recognition (Experiment 1), vocal timbre (Experiment 2), or the absolute pitch of target recordings (i.e., the advantage remains when recordings are transposed, Experiment 3). Results support the conceptualization of poor-pitch singing as an imitative deficit resulting from a deficient inverse model of the auditory-vocal system with respect to pitch.

Individuals with congenital amusia imitate pitches more accurately in singing than in speaking: implications for music and language processing.

In this study, we investigated the impact of congenital amusia, a disorder of musical processing, on speech and song imitation in speakers of a tone language, Mandarin. A group of 13 Mandarin-speaking individuals with congenital amusia and 13 matched controls were recorded while imitating a set of speech and two sets of song stimuli with varying pitch and rhythm patterns. The results indicated that individuals with congenital amusia were worse than controls in both speech and song imitation, in terms of both pitch matching (absolute and relative) and rhythm matching (relative time and number of time errors). Like the controls, individuals with congenital amusia achieved better absolute and relative pitch matching and made fewer pitch interval and contour errors in song than in speech imitation. These findings point toward domain-general pitch (and time) production deficits in congenital amusia, suggesting the presence of shared pitch production mechanisms but distinct requirements for pitch-matching accuracy in language and music processing.

Vocal imitation of song and speech.

We report four experiments that explored the cognitive bases of vocal imitation. Specifically, we investigated the accuracy with which normal individuals vocally imitated the pitch-time trajectories of spoken sentences and sung melodies, presented in their original form and with phonetic information removed. Overall, participants imitated melodies more accurately than sentences with respect to absolute pitch but not with respect to relative pitch or timing (overall duration). Notably, the presence of phonetic information facilitated imitation of both melodies and speech. Analyses of individual differences across studies suggested that the accuracy of imitating song predicts accuracy of imitating speech. Overall, these results do not accord with accounts of modular pitch processing that emphasize information encapsulation.

Effects of altered auditory feedback across effector systems: production of melodies by keyboard and singing.

We report an experiment that tested whether effects of altered auditory feedback (AAF) during piano performance differ from its effects during singing. These effector systems differ with respect to the mapping between motor gestures and pitch content of auditory feedback. Whereas this action-effect mapping is highly reliable during phonation in any vocal motor task (singing or speaking), mapping between finger movements and pitch occurs only in limited situations, such as piano playing. Effects of AAF in both tasks replicated results previously found for keyboard performance (Pfordresher, 2003), in that asynchronous (delayed) feedback slowed timing whereas alterations to feedback pitch increased error rates, and the effect of asynchronous feedback was similar in magnitude across tasks. However, manipulations of feedback pitch had larger effects on singing than on keyboard production, suggesting effector-specific differences in sensitivity to action-effect mapping with respect to feedback content. These results support the view that disruption from AAF is based on abstract, effector independent, response-effect associations but that the strength of associations differs across effector systems.