The biological basis of speech: What to infer from talking to the animals.

Abstract

Speech perception and production are uniquely human adaptations. The mechanisms and laws that these adaptations implicate are tuned to linguistic rather than general auditory phenomena, leading to the view that speech is special (SiS). Despite the progress made by proponents of SiS, a small but growing "auditorist" program critical of SiS conscripts nonhuman animals such as quail and chinchilla and, using discrimination tasks on speech stimuli, incorrectly infers a common mechanism from similar cross-species performance. The author argues that the auditorist's refutation project must demonstrate not just cross-species isomorphisms of behavior but also either a common biological mechanism or common functional organization. The refutation project does neither. The author argues further that the auditorist's appeal to the principle of parsimony fails. Respect for the total available evidence undermines auditorism and bolsters SiS.

Enhanced production and perception of musical pitch in tone language speakers

“…Specifically, the discrimination of lexical tones in a linguistic context (as opposed to a nonlinguistic context) increases activations in the left inferior frontal gyrus (Broca's area) for tone language speakers but not for individuals unfamiliar with the language (including intonation language speakers; Gandour et al 2000;Gandour, Wong, & Hutchins, 1998;Wong, Parsons, Martinez, & Diehl, 2004). These results follow from a long-standing idea that speech perception relies on speech-specific neural mechanisms (Liberman, Cooper, Shankweiler, & Studdert-Kennedy, 1967;Liberman & Mattingly, 1985;Peretz & Zatorre, 2005;Remez, Rubin, Berns, Pardo, & Lang, 1994;Trout, 2001; but see Galantucci, Fowler, & Turvey, 2006, for a critique of this perspective). Similarly, a recent neuropsychological model of music and language includes the claim that the processing of pitch may be performed by domain-specific and independent modules, depending on whether pitch appears in a linguistic or a musical context (Peretz & Coltheart, 2003).…”

The faculty of language: what's special about it?

“…Neuroimaging and brain-damage studies suggest that partly distinct sets of brain areas subserve speech and non-speech sounds (Hickok & Poeppel, 2000;Poeppel, 2001;Trout, 2001;Vouloumanos, Kiehl, Werker, & Liddle, 2001). A clear example is pure word deafness, in which a neurological patient has lost the ability to analyze speech while recognizing other environmental sounds (Hickok & Poeppel, 2000;Poeppel, 2001).…”

“…It is not surprising that some animals can do so, or even that their perceptual boundaries resemble those of humans, since auditory analyzers suited for nonspeech distinctions might suffice to discriminate among speech sounds, even if the analyzers humans use are different (Trout, 2001(Trout, , 2003b. For example, a mammalian circuit that uses onset asynchrony to distinguish two overlapping auditory events from one event with a complex timbre might be sufficient to discriminate voiced from unvoiced consonants (Bregman & Pinker, 1978).…”

“…Moreover, there is considerable evidence that has cast doubt on the null hypothesis (Anderson, 2004;Liberman, 1985Liberman, , 1991Remez, 1989Remez, , 1994Trout, 2001Trout, , 2003b. First, speech and sound are phenomenologically different: under certain conditions, a given sound can be perceived simultaneously as part of a syllable and as a non-speechlike chirp (Liberman & Mattingly, 1989), or a stretch of sound can be heard to flip qualitatively between speech and non-speech (Remez, Pardo, Piorkowski, & Rubin, 2001).…”

Incidental categorization of spectrally complex non-invariant auditory stimuli in a computer game task

“…Though, like many phonetic categories of the world's languages, onset categories 1 and 2 could not be differentiated by any single invariant acoustic cue, listeners ͑experiment 1, condition 1͒ learned the sounds, even without feedback or instructions to learn the categories. Together with the fact that nonhuman animals can learn similarly noninvariant speech categories ͑Kluender et al, 1987͒, this finding is consistent with an account of speech perception that exploits general learning mechanisms for phonetic acquisition ͑Diehl, et al, 2004͒ rather than specialized processes ͑e.g., Liberman and Mattingly, 1985;1989;Trout, 2001͒. Learning in the game was also compared with that resulting from an explicit unsupervised categorization task in experiment 2. An interaction involving category type was observed, such that game participants showed relatively more learning for the non-invariant onset categories requiring cue integration.…”