Читать книгу The Handbook of Speech Perception - Группа авторов - Страница 57

K. G. MUNHALL¹, ANJA‐XIAOXING CUI², ELLEN O’DONOGHUE³, STEVEN LAMONTAGNE¹, AND DAVID LUTES¹

¹ Queen’s University, Canada

² University of British Columbia, Canada

³ University of Iowa, United States

There is broad agreement that the American socialite Florence Foster Jenkins was a terrible singer. Her voice was frequently off‐key and her vocal range did not match the pieces she performed. The mystery is how she could not have known this. However, many – including her depiction in the eponymous film directed by Stephen Frears – think it likely that she was unaware of how poorly she sang. The American mezzosoprano Marilyn Horne offered this explanation. “I would say that she maybe didn’t know. First of all, we can’t hear ourselves as others hear us. We have to go by a series of sensations. We have to feel where it is” (Huizenga, 2016). This story about Jenkins contains many of the key questions about the topic of this chapter, the perceptual control of speech. Like singing, speech is governed by a control system that requires sensory information about the effects of its actions, and the major source of this sensory feedback is the auditory system. However, the speech we hear is not what others hear and yet we are able to control our speech motor system in order to produce what others need or expect to hear. For both speech and singing, much is unknown about the auditory‐motor control system that accomplishes this. What role does hearing your voice play in error detection and correction? How does this auditory feedback processing differ from how others hear you? What role does hearing your voice play in learning to speak?

Human spoken language has traditionally been studied by two separate communities (Meyer, Huettig, & Levelt, 2016): those including the majority of contributors to this volume who study the perception of speech signals produced by others and those who study the production of the speech signal itself. It is the latter that is the focus of this chapter. More specifically, the chapter focuses on the processing of the rich sensory input accompanying talking, particularly hearing your own voice. As Marilyn Horne suggests, perceiving this auditory feedback is not the same as hearing others. Airborne speech sound certainly arrives at the speaker’s ear as it does at the ears of others, but for the speaker it is mixed with sound transmitted through the body (e.g. Békésy, 1949). A second difference between hearing yourself and hearing others is neural rather than physical. The generation of action in speech and other movements is accompanied by information about the motor commands that is transmitted from the motor system to other parts of the brain that might need to know about the movement. One consequence of this distribution of copies of motor commands is that the sensory processing of the effects of a movement is different from the processing of externally generated sensory information (see Bridgeman, 2007, for a historical review).

This chapter addresses a number of issues related to the perceptual control of speech production. We first examine the importance of hearing yourself speak through the study of natural and experimental deafening in humans and birds. This work is complemented by recent work involving real‐time manipulations of auditory feedback through rapid signal processing. Next, we review what is known about the neural processing of self‐produced sound. This includes work on corollary discharge or efference copy, as well as studies showing cortical suppression during vocalizing. Finally, we address the topic of vocal learning and the general question about the relationship between speech perception and speech production. A small number of species including humans learn their vocal repertoire. It is important to understand the conditions that promote this learning and also to understand why this learning is so rare. Through all of our review, we will touch base with research on birdsong. Birdsong is the animal model of human vocal production. The literature on birdsong provides exciting new research directions as extensive projects on the genetic and neural underpinnings of vocal learning are carried out demonstrating remarkable similarity to human vocal behavior (Pfenning et al., 2014).