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This paper reviews Bloodstein's (1975) Anticipatory Struggle Hypothesis of stuttering, identifies its weaknesses, and proposes modifications to bring it into line with recent advances in psycholinguistic theory. The review concludes that the Anticipatory Struggle Hypothesis provides a plausible explanation for the variation in the severity of stuttered disfluencies across speaking situations and conversation partners. However, it fails to explain the forms that stuttered disfluencies characteristically take or the subjective experience of loss of control that accompanies them. The paper then describes how the forms and subjective experiences of persistent stuttering can be accounted for by a threshold-based regulatory mechanism of the kind described in Howell's (2003) revision of the EXPLAN hypothesis. It then proposes that shortcomings of both the Anticipatory Struggle and EXPLAN hypotheses can be addressed by combining them together to create a ‘Variable Release Threshold’ hypothesis whereby the anticipation of upcoming difficulty leads to the setting of an excessively high threshold for the release of speech plans for motor execution. The paper also reconsiders the possibility that two stuttering subtypes exist: one related to formulation difficulty and other to difficulty initiating motor execution. It concludes that research findings that relate to the one may not necessarily apply to the other. Learning outcomes: After reading this article, the reader will be able to: (1) summarize the key strengths and weaknesses of Bloodstein's Anticipatory Struggle Hypothesis; (2) describe two hypothesized mechanisms behind the production of stuttered disfluencies (tension and fragmentation & release threshold mechanisms); and (3) discuss why the notion of anticipation is relevant to current hypotheses of stuttering. [Copyright &y& Elsevier]

Abstract: This study investigates whether the experience of stuttering can result from the speaker''s anticipation of his words being misrecognized. Twelve adults who stutter (AWS) repeated single words into what appeared to be an automatic speech-recognition system. Following each iteration of each word, participants provided a self-rating of whether they stuttered on it and the computer then provided feedback implying its correct or incorrect recognition of it. Each word was repeated four times. Unbeknown to participants, ‘Correct’ and ‘Incorrect’ recognition of words by the system was pre-determined and bore no relation to the actual quality of participants’ iterations of those words. For words uttered in the ‘Correct recognition’ condition, the likelihood of AWS self-reporting stuttering on a word diminished across iterations, whereas for words in the ‘Incorrect recognition’ condition it remained static. On the basis of the findings it is argued that: (a) in AWS, the anticipation that a word will be misrecognized increases the relative likelihood of stuttering on that word in the future; and (b) this effect is independent of the degree of difficulty inherent in the formulation and motor execution of the word itself, although it may interact with it. Mechanisms that can account for these findings and yet are also congruent with the wider range of evidence from psycholinguistic and speech motor control domains are discussed. It is concluded that stuttered disfluencies may best be explained as resulting from the inappropriate functioning of covert repair and/or variable release threshold mechanisms in response to the anticipation of communication failure. Learning outcomes: This article informs readers about two different theoretical approaches to explaining developmental stuttering: (1) stuttering as an adaptation response to an underlying impairment; and (2) stuttering as an anticipatory struggle response. It describes how these approaches account for different symptoms of the disorder, and proposes that both theoretical approaches are needed in order to fully account for the range of symptoms and experimental findings associated with stuttering. [Copyright &y& Elsevier]