Petra Eccarius

Brief Report: Visuo-spatial Guidance of Movement during Gesture Imitation and Mirror Drawing in Children with Autism Spectrum Disorders

Thirteen autistic and 14 typically developing children (controls) imitated hand/arm gestures and performed mirror drawing; both tasks assessed ability to reorganize the relationship between spatial goals and the motor commands needed to acquire them. During imitation, children with autism were less accurate than controls in replicating hand shape, hand orientation, and number of constituent limb movements. During shape tracing, children with autism performed accurately with direct visual feedback, but when viewing their hand in a mirror, some children with autism generated fewer errors than controls whereas others performed much worse. Large mirror drawing errors correlated with hand orientation and hand shape errors in imitation, suggesting that visuospatial information processing deficits may contribute importantly to functional motor coordination deficits in autism.

Sign Languages: Handshape contrasts in sign language phonology

Of the five parameters of sign language structure – handshape, movement, place of articulation, orientation and nonmanual behaviors – handshape is the parameter that has been analyzed most successfully with a variety of methodologies, both theoretical and experimental. Since it is here that we find themost complete body of work to draw upon, we have chosen to examine handshape behavior as a way of better understanding the nature of phonological contrast in signed languages. The goal of this chapter is twofold. First we will draw attention to the range of variation in the form and use of handshapes, and second, we will analyze the distribution of handshape properties. We will also investigate these issues both crosslinguistically and language-internally in order to determine which features are phonologically contrastive and where they are contrastive in the lexicon. In order to achieve our goal of showing how sign languages use handshape in their phonological systems, a little background is necessary on both the organization of a sign language lexicon and the phonological structure of signed languages. After covering this introductory material and our methodology in sections 1 and 2, we will describe differences in the way that handshape feature classes are used across the three components of the lexicon (foreign, core and spatial) in three different sign languages – namely, American Sign Language (ASL), Swiss German Sign Language (DSGS) and Hong Kong Sign Language (HKSL). In sections 3–5, we analyze specific distributions of two types of handshape properties – selected fingers and joint configuration – across the lexicon and across different classifiers types. Evidence will be presented showing (1) that both selected finger combinations and joint configurations can behave differently across the lexicon, and (2) that even among different types of classifier handshapes, there are systematic distributional differences regarding these properties, due in part to the link between morphology and iconicity. In section 6, we address the theoretical consequences of our results. We begin the section by discussing recent work in

A constraint-based account of distributional differences in handshapes

In sign languages, as with spoken languages, phonological distributions and behaviors are rarely homogeneous, either across languages or within them. This is largely due to conflicting forces influencing language change, such as internal pressures to ease articulation and/or perception and external influences from language contact. Degree of iconicity can also play a role in these varied phonological behaviors, especially (but not exclusively) in sign language forms. But how should such a complex system of linguistic pressures be represented theoretically? Ideally, phonological representation of such distributional variation should be able to incorporate the many kinds of conflicting forces that contribute to it, and fortunately, Optimality Theory affords us an opportunity to do just that. Optimality Theory (Prince and Smolensky 1993) considers language to be a system of conflicting forces expressed by means of violable linguistic constraints. The two main forces in this approach are Markedness, which assumes systems prefer unmarked structures, and Faithfulness, which assumes systems prefer to maintain lexical contrasts. Markedness is typically grounded in factors like articulation and perception, while Faithfulness is primarily concerned with making sure that the system has enough contrasts available to convey the necessary differences in meaning. The optimal output form is then determined according to language particular rankings of these constraints. In this work I use a combination of established branches of Optimality Theory (OT) to explain distributional differences in handshape contrasts occurring as a result of conflicting pressures. First, I follow Flemming’s (2002) version of OT, Dispersion Theory, in which grammars balance the system-internal pressures of articulatory ease and perceptual distinctiveness, as well as the desire to maximize the number of contrasts available in word formation. Then, based on the work of Ito and Mester (1995a), I add pressures to maintain contrasts borrowed into languages from external sources.

When does a system become phonological? Potential sources of handshape contrast in sign languages

This chapter addresses how a phonological system might emerge in a sign language; in other words, it asks the question, “What are some potential paths to phonological contrast?” Distinctive contrasts (those that achieve minimal pairs) and allophonic alternations (those used in phonological rules) are the two most commonly studied types of distributions in phonological systems. Both exist in sign languages, but we will argue that we can learn a great deal about how the human mind comes to create phonology if we look beyond these types of distribution, (i.e., those most common in spoken languages). In particular, we will describe two phenomena, one involving a grammatical interface between morphology and phonology and the other involving a grammatical interface between phonetics and phonology. We propose that the interfaces are a good place to look for the seeds of phonology in homesign systems and in young sign languages. We use language internal evidence, crosslinguistic data, and data from homesigners. The general argument is as follows. Distinctive and allophonic distributions are common in spoken languages but not in sign languages (Brentari & Eccarius 2010, Eccarius & Brentari 2008). A distinctive distribution is a case where unrelated lexemes are distinguished by the presence or absence of a feature or feature structure. For example, in English /b/ in “bit” (verb/past tense) and /p/ in “pit” (definite noun) are distinguished by [voice]. In ASL, CAR (noun) and WHICH (wh-word) is a similar case of distinctive contrast in which two unrelated lexical items are distinguished by the absence or presence of the extended thumb. It has been observed that sign languages have very few minimal pairs, even in well-established sign languages (van der Kooij 2002, van der Hulst & van der Kooij 2006, Eccarius 2008). Van der Hulst and van der Kooij (2006) argue that this is due in part to phonetic possibilities; there is a larger number of different articulators and a larger perceptual space that contribute to the phonological system compared with that of

Effects of Character Geometric Model on Perception of Sign Language Animation

This paper reports a study that aimed to determine whether character geometric model (i.e. segmented vs.seamless) has an effect on how animated signing is perceived by viewers. Additionally, the study investigated whether the geometric model affects perception at varying degrees of linguistic complexity--specifically handshape complexity. We modeled and animated two polygonal 3D characters: Torrents,one seamless mesh, and Robby, a fully segmented avatar. Both characters had similar geometrical proportions, identical skeletal systems, similar visual styles and color schemes, and met standards of good character design. Each signed 60stimulus signs, divided into three groups—those with simple(group I), moderately complex (group II), and complex (groupIII) handshapes according to factors established in the linguistic literature. 53 participants, who learned ASL by age5, viewed animated clips in random order via web survey. They(1) identified the sign (if recognizable), and (2) rated its realism using a 5-point Likert scale. Findings show that the seamless avatar (Torrents) was rated highest, and simple handshapes were rated higher than moderately complex and complex ones.The interaction between character and handshape complexity was also significant. For Robby (more than for Torrents),ratings decreased as handshape complexity increased. The lower ratings for Robby could indicate a preference for seamless, deformable characters over segmented ones, especially in signs with complex handshapes.