The role of variation in the perception of accented speech

Phonetic variation has been considered a barrier that listeners must overcome in speech perception, but has been proved beneficial in category learning. In this paper, I show that listeners use within-speaker variation to accommodate gross categorical variation. Within the perceptual learning paradigm, listeners are exposed to p-initial words in English produced by a native speaker of French. Critically, listeners are trained on these words with either invariant or highly-variable VOTs. While a gross boundary shift is made for participants exposed to the variable VOTs, no such shift is observed after exposure to the invariant stimuli. These data suggest that increasing variation improves the mapping of perceptually mismatched stimuli.     

Motor programming in apraxia of speech

Apraxia of Speech (AOS) is an impairment of motor programming. However, the exact nature of this deficit remains unclear. The present study examined motor programming in AOS in the context of a recent two-stage model [Klapp, S. T. (1995). Motor response programming during simple and choice reaction time: The role of practice. Journal of Experimental Psychology: Human Perception and Performance, 21, 1015–1027; Klapp, S. T. (2003). Reaction time analysis of two types of motor preparation for speech articulation: Action as a sequence of chunks. Journal of Motor Behavior, 35, 135–150] that proposes a preprogramming stage (INT) and a process that assigns serial order to multiple programs in a sequence (SEQ). The main hypothesis was that AOS involves a process-specific deficit in the INT (preprogramming) stage of processing, rather than in the on-line serial ordering (SEQ) and initiation of movement. In addition, we tested the hypothesis that AOS involves a central (i.e., modality-general) motor programming deficit. We used a reaction time paradigm that provides two dependent measures: study time (the amount of time for participants to ready a motor response; INT), and reaction time (time to initiate movement; SEQ). Two experiments were conducted to examine INT and SEQ in AOS: Experiment 1 involved finger movements, Experiment 2 involved speech movements analogous to the finger movements. Results showed longer preprogramming time for patients with AOS but normal sequencing and initiation times, relative to controls. Together, the findings are consistent with the hypothesis of a process-specific, but central (modality-independent) deficit in AOS; alternative explanations are also discussed.     

Investigating speech motor practice and learning in people who stutter

In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS.

Educational objectives: The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.     

Learning to fail: reoccurring tip-of-the-tongue states

This experiment looked at elicited tip-of-the-tongue (TOT) states to test the hypothesis that making an error once makes people more likely to make it again, via an implicit learning mechanism. We present a methodology that allows us to determine whether error reoccurrences are due to error learning or to the fact that some items tend to pose repeated difficulty to participants. We elicited TOTs by asking participants to supply the word that fitted a given definition. Each time participants indicated that they were experiencing a TOT they were randomly assigned a delay of either 10 or 30 seconds, during which they were asked to keep trying to retrieve the item. After the delay, the correct answer was supplied. We argue that this longer delay in a TOT state amounts to greater implicit learning of the erroneous state. A period of 48 hours later, participants returned to the laboratory and were asked to supply the words for the same definitions as those seen on Day 1. Results showed that TOTs were almost twice as likely to reoccur on words that had elicited a TOT and been followed by a long delay than on those that had been followed by a short delay.     

The link between speech perception and production is phonological and abstract: evidence from the shadowing task

This study reports a shadowing experiment, in which one has to repeat a speech stimulus as fast as possible. We tested claims about a direct link between perception and production based on speech gestures, and obtained two types of counterevidence. First, shadowing is not slowed down by a gestural mismatch between stimulus and response. Second, phonetic detail is more likely to be imitated in a shadowing task if it is phonologically relevant. This is consistent with the idea that speech perception and speech production are only loosely coupled, on an abstract phonological level.     

EDUCATION SECTION: Infant observation in Britain:The Tavistock approach

The author draws attention to something distinctive in the psychoanalytic 'air' from the early 1960s onwards: the strong emphasis upon the very early psychological, emotional and cognitive view of infants and young children. She focuses on the work of two analysts in particular, Esther Bick and Wilfred Bion, and the comparable, though differently expressed, centrality of the observational method in their work. Each explored not only the pathological picture but also the nature and integrative function of psychic containment in earliest mental life. Each also shared a preoccupation with what constituted a psychoanalytic attitude and with the process of becoming a psychoanalyst and, in Bick's case, a child analyst or psychotherapist. The author provides an historical background to the idea of observation, followed by an account, with detailed examples, of the nature of infant observation and the observational method as taught and practised at the Tavistock Clinic, London since the late 1940s, and subsequently in many other training institutions. Here the themes of Bick and Bion are constantly interrelated such that the prototype or model for the creation of emotional meaning and thought can be appreciated and learning from experience can take place.     

Beyond babytalk: Re-evaluating the nature and content of speech input to preverbal infants

Infant-directed maternal speech is an important component of infants’ linguistic input. However, speech from other speakers and speech directed to others constitute a large amount of the linguistic environment. What are the properties of infant-directed speech that differentiate it from other components of infants’ speech environment? To what extent should these other aspects be considered as part of the linguistic input? This review examines the characteristics of the speech input to preverbal infants, including phonological, morphological, and syntactic characteristics, specifically how these properties might support language development. While maternal, infant-directed speech is privileged in the input, other aspects of the environment, such as adult-directed speech, may also play a role. Furthermore, the input is variable in nature, dependent on the age and linguistic development of the infant, the social context, and the interaction between the infant and speakers in the environment.     

Dynamic action units slip in speech production errors

In the past, the nature of the compositional units proposed for spoken language has largely diverged from the types of control units pursued in the domains of other skilled motor tasks. A classic source of evidence as to the units structuring speech has been patterns observed in speech errors--"slips of the tongue". The present study reports, for the first time, on kinematic data from tongue and lip movements during speech errors elicited in the laboratory using a repetition task. Our data are consistent with the hypothesis that speech production results from the assembly of dynamically defined action units--gestures--in a linguistically structured environment. The experimental results support both the presence of gestural units and the dynamical properties of these units and their coordination. This study of speech articulation shows that it is possible to develop a principled account of spoken language within a more general theory of action.     

Comprehension of main ideas and details in coherent and noncoherent discourse by aphasic and nonaphasic listeners

Aphasic and nonaphasic listeners' comprehension of main ideas and details within coherent and noncoherent narrative discourse was examined. Coherent paragraphs contained one topic to which all sentences in the paragraph related. Noncoherent paragraphs contained a change in topic with every third or fourth sentence. Each paragraph contained four main ideas and one or more details that related to each main idea. Listeners' responses to yes/no questions following each paragraph yielded the following results: (1) Nonaphasic listeners comprehended the paragraphs better than aphasic listeners. (2) Both aphasic and nonaphasic listeners comprehended main ideas better than they comprehended details. (3) Coherence did not affect comprehension of main ideas for either group. (4) Coherence did not affect comprehension of details by nonaphasic subjects. (5) Coherence affected comprehension of details by aphasic subjects, and their comprehension of details in coherent paragraphs was worse than their comprehension of details in noncoherent paragraphs. There was no significant correlation between Token Test scores and measures of paragraph comprehension.