Online research in philosophy

Sussman et al. describe an ecological property of the speech signal that is putatively functional in perception. An important issue, however, is whether their putative cue is an emerging feature or whether the second formant (F2) onset and the F2 vowel actually provide independent cues to perceptual categorization. Regardless of the outcome of this issue, an important goal of speech research is to understand how multiple cues are evaluated and integrated to achieve categorization.

There is a thriving debate over what aspects of our capacity to produce and understand language are special. My concern here is a key part of this wider debate: Is speech special? In particular, my focus is on speech perception, and whether it is special. This isn’t just one but a number of different questions. Too frequently, these very different questions are not clearly distinguished and kept apart. I discuss a framework for distinguishing various versions of the question, Is speech perceptually special? Focusing on a particular class of questions, I make a proposal about the sense in which speech is perceptually special. According to this account, the capacity to perceive speech is an acquired perceptual skill, and involves learning to hear language-specific types of biologically-significant sounds. This account illuminates the significance of interlocution in understanding what makes the perception of speech distinctive.

We urge caution in generalising from content words to function words, in which lexical-to-phonemic feedback might be more likely. Speech perception involves more than word recognition; feedback might be outside the narrow logic of word identification but still be present for other purposes. Finally, we raise the issue of evidence from imaging studies of auditory hallucination.

Pickering & Garrod's (P&G's) mechanistic account of dialogue assumes that linguistic alignment between interlocutors takes place automatically, without using cognitive resources. However, even the most basic processes of speech perception depend on resource use. The lack of invariant mapping between input patterns and interpretations in dialogue, as in speech perception, may require controlled, rather than automatic, processing.

Can humans see causal interactions? Evidence on the visual perception of causal interactions, from Michotte to contemporary work, is best interpreted as showing that we can see some causal interactions in the same sense as that in which we can hear speech. Causal perception, like speech perception, is a form of categorical perception.

Although sensorimotor contingencies may explain visual perception, it is difficult to extend this concept to speech perception. However, the basic concept of perception as active hypothesis testing using attention does extend well to speech perception. We propose that the concept of sensorimotor contingencies can be broadened to sensory-attentional contingencies, thereby accounting for speech perception as well as vision.

The effort to understand speech perception on the basis of relationships between acoustic parameters of speech sounds is to be recommended. Neural specializations (combination-sensitivity) for echolocation, communication, and sound localization probably constitute the common mechanisms of vertebrate auditory processing and may be essential for speech production as well as perception. There is, however, no need for meaningful maps.

In this paper I provide a metatheoretical analysis of speech perception research. I argue that the central turning point in the history of speech perception research has not been well understood. While it is widely thought to mark a decisive break with what I call "the alphabetic conception of speech," I argue that it instead marks the entrenchment of this conception of speech. In addition, I argue that the alphabetic conception of speech continues to underwrite speech perception research today and moreover that it functions as a dogma which ought to be rejected.

The suggestion that analytic isomorphism should be rejected applies especially to the domain of speech perception because (1) the guiding assumption that solving the lack of invariance problem is the key to explaining speech perception is a form of analytic isomorphism, and (2) after nearly half a century of research there is virtually no empirical evidence of isomorphism between perceptual experience and lower-level processing units.

Fodor argues that speech perception is accomplished by a module. Typically, modular processing is taken to be bottom-up processing. Yet there is ubiquitous empirical evidence that speech perception is influenced by top-down processing. Fodor attempts to resolve this conflict by denying that modular processing must be exclusively bottom-up. It is argued, however, that Fodor's attempt to reconcile top-down and modular processing fails, because: (i) it undermines Fodor's own conception of modular processing; and (ii) it cannot account for the contextually varying top-down influences that characterize speech perception.