The emergence of the formal category “symmetry” in a new sign language

Abstract

Logical properties such as negation, implication, and symmetry, despite the fact that they are foundational and threaded through the vocabulary and syntax of known natural languages, pose a special problem for language learning. Their meanings are much harder to identify and isolate in the child's everyday interaction with referents in the world than concrete things (like spoons and horses) and happenings and acts (like running and jumping) that are much more easily identified, and thus more easily linked to their linguistic labels (spoon, horse, run, jump). Here we concentrate attention on the category of symmetry [a relation R is symmetrical if and only if (iff) for all x, y: if R(x,y), then R(y,x)], expressed in English by such terms as similar, marry, cousin, and near. After a brief introduction to how symmetry is expressed in English and other well-studied languages, we discuss the appearance and maturation of this category in Nicaraguan Sign Language (NSL). NSL is an emerging language used as the primary, daily means of communication among a population of deaf individuals who could not acquire the surrounding spoken language because they could not hear it, and who were not exposed to a preexisting sign language because there was none available in their community. Remarkably, these individuals treat symmetry, in both semantic and syntactic regards, much as do learners exposed to a previously established language. These findings point to deep human biases in the structures underpinning and constituting human language. language emergence | sign language | logical structure of language | homesign | symmetry T o a first approximation, language describes the entities-the lions, spoons, puppies-and events-the running, chasing, eating-that figure in everyday life. However, an immediate counter, or at least refinement, of this view of language is that events, as well as entities, can be construed in more than one way, a distinction that is reflected in the lexical forms and structures of all known languages. For example, the same event could equally be described as "a lion chasing a gnu" or "a gnu fleeing a lion." What is seen in the ambient world is the same, but, in one case, it is viewed from the perspective of the causal agent (the lion) and, in the other, from the perspective of the potential victim (the gnu). Assembling a sentence is not just a matter of mentioning the gnu and the lion and the running, but necessarily entails a perspective on the events under description, their construal. Indeed, it is not the events per se that sentences encode; it is their construals.This presents a puzzle: the construal of an event is abstract and not observable per se. How would a learner of a language come to appreciate the relevant encoding, and how would such distinctions arise in a new language?We examine the foundations of this core distinction between observation and construal by first gleaning insights about its encoding from a mature language, English. We then explore experimentally whether and when such a distinct...

Where word and world meet: Language and vision share an abstract representation of symmetry.

“…Finally, Gleitman et al,’s (2019) recent empirical findings that the formal category of symmetry is expressed spatially in an emerging sign language (NSL) provide compelling evidence that the link between linguistic symmetry and visual symmetry in the mind has its basis in an amodal conceptual representation of symmetry, rather than in purely sensorimotor representations or explicit analogical processes. To understand why, consider the “projectibility problem” posed by symmetrical predicates (Goodman, 1955): the learner must infer that symmetry holds for all possible pairs ( x , y ) in a given relation despite exposure to only a finite number of instances ( R ( x 1 , y 1 ) and R ( y 1 , x 1 ), R ( x 2 , y 2 ) and R ( y 2 , x 2 ), etc.).…”

“…Beyond revealing how representations of symmetry correspond across different cognitive systems, answering these questions will also shed light on how children might learn symmetrical terms and how adults represent them. In particular, the abstract nature of symmetrical meanings presents a problem for the language learner, who must discover which words map onto which concepts (Fisher et al, 2020; Gleitman, 1990; Gleitman et al, 2019; Landau & Gleitman, 1985)—a process which, especially for symmetrical concepts, requires projecting from a finite set of instances to a more general and lawlike property (Goodman, 1955). A correspondence between linguistic and visual representations of symmetry may thus be part of the toolkit the learner uses to solve this problem (a possibility we outline in more detail in the General Discussion).…”

Learning to predict and predicting to learn: Before and beyond the syntactic bootstrapper

“…We plan to test prediction adaptation in Hebrew and Arabic ourselves. We believe it is also extremely important to test syntactic (or more generally, structural) bootstrapping, prediction of utterance ending and adaptation in Signed languages as well (see e.g., Gleitman et al, 2019). Without taking a broader look at whether and how these mechanisms play a role in diverse languages and situations, we cannot know to what extent current findings are generalizable, and whether they are restricted to some very specific European languages.…”

Discovering the Biases Children Bring to Language Learning

“…Sessions were videotaped for later coding and analysis (see Goldin‐Meadow, 2003a, for details). Adults were shown vignettes of carefully chosen scenes and asked to describe them (e.g., Gleitman, Senghas, Flaherty, Coppola, & Goldin‐Meadow, 2019; Goldin‐Meadow, Brentari, Coppola, Horton, & Senghas, 2015).…”

“…Another example of homesigners eschewing veridical depiction comes from verb forms used to express symmetrical versus reciprocal relations (Gleitman et al, 2019). For example, consider the symmetrical relation of high‐fiving, performed by two people doing the same movements at the same time to form a single act.…”