PhD for Alan Nielsen

By Kenny | May 10, 2016

Congratulations to Dr Alan Nielsen, who was awarded his PhD on 10th May – Alan’s thesis was titled “Systematicity, Motivatedness, and the Structure of the Lexicon”, and was supervised by Kenny Smith and Simon Kirby.

The LEC is becoming the Centre for Language Evolution

By Kenny | May 6, 2016

We’re evolving! The Language Evolution and Computation Research Unit was established back in 1997 by Jim Hurford and Simon Kirby, and has grown substantially since then to become (we think) the world’s leading group of researchers working on language origins and evolution. To reflect our increased size, and also the increased breadth of the techniques we use (we still build computational models, but it’s not all we do), we’ve decided to rebrand as the Centre for Language Evolution. Look out for a our website and logo, appearing here soon.

CLE talk 3 May: James Kirby & Morgan Sonderegger

By jon | April 27, 2016

Tuesday 3 May, 11:00–12:30
1.17 Dugald Stewart Building

James Kirby (Edinburgh) & Morgan Sonderegger (McGill)

Population dynamics in the actuation of sound change

Sound change arises from the pronunciation variability ubiquitous in every speech community, but most such variability does not lead to change. Hence, an adequate model must allow for stability as well as change. Existing theories of sound change tend to emphasize factors at the level of individual learners promoting one outcome or the other, such as channel bias (which favors change) or inductive bias (which favors stability). Here, we consider how the interaction of these biases can lead to both stability and change in a population setting.

First, we show that while population structure itself can act as a source of stability, both stability and change are possible outcomes only when both types of bias are active, suggesting that it is possible to understand why sound change occurs at some times and not others as the population-level result of the interplay between forces promoting each outcome in individual speakers. We then discuss how this account of actuation may be generalized to at least two other cases where change can occur without production bias: contact between subpopulations, and phonetic variants which bear different levels of prestige. We show how phonetic systems can remain stable under a variety of perturbations, such as lenition, contact, and social prestige, depending on the relative magnitudes of the biases involved. This result suggest a more unified account of the mechanics of actuation, with the crucial factor being the relative magnitude, rather than the specific source, of the displacement event.

LEC talk 9 February: Kenny Smith

By jon | February 3, 2016

Tuesday 9 February, 11:00–12:30
1.17 Dugald Stewart Building

Kenny Smith (work with Deborah Kerr, MSc ELC 2014/15)

The Spontaneous Emergence of Linguistic Diversity in an Artificial Language

I will present an experimental paradigm, combining artificial language learning with the Minimal Group method borrowed from social psychology, and demonstrate the spontaneous emergence of linguistic diversity despite the absence of functional pressures for social differentiation.

Longer abstract here

LEC talk Tuesday 2 February: Christine Cuskley

By jon | January 29, 2016

Tuesday 2 February, 11:00–12:30
1.17 Dugald Stewart Building

Christine Cuskley

Frequency and Stability in Linguistic Rules

Frequency and stability exhibit an interesting relationship in language: the more frequent a linguistic construction is, the less it tends to change over time. Despite this evident relationship, it is less clear what specific social and cognitive factors cause increased stability in more frequent constructions. This talk will present work which aims to examine the specific factors underlying the frequency-stability relationship using the test case of verb regularity in English: highly frequent verbs are more likely to be irregular, while less frequent verbs tend to destabilise to the regular form. To investigate this, I will present analysis from a historical corpus of English showing that vocabulary growth underlies the most marked increases in regularity over time, and verbs transition from irregular to regular and visa versa within a particular frequency band. In another approach to the problem, an adaptation of the Naming Game sheds light on the dynamics of rules and irregular exceptions across a population of interacting agents. Finally, I present an experiment which contrasts how native and non-native speakers inflect novel verbs to investigate how differences in population structure might affect regularity in a language system. Together, these results help us to better understand what causes the persistence of irregular exceptions to regular rules in language more generally, and how sociolinguistic and demographic processes may effect regularity.

Major research grant for Kenny Smith

By Simon Kirby | January 25, 2016

Kenny has been successful in securing a major 5 year grant from the European Research Council to investigate the Evolution of Linguistic Complexity. Well done, Kenny!

LEC talk Thursday 14 January: Judith Degen

By jon | January 6, 2016

NOTE UNUSUAL DAY AND LOCATION

Thursday 14 January, 11:00–12:30
Lecture Theatre 3, 7 Bristo Square

Judith Degen, Department of Psychology, Stanford University

Context in pragmatic inference

In the face of underspecified utterances, listeners routinely and without much apparent effort make the right kinds of pragmatic inferences about a speaker’s intended meaning. I will present a series of studies investigating the processing of one type of inference – scalar implicature – as a way of addressing how listeners perform this remarkable feat. In particular, I will explore the role of context in the processing of scalar implicatures from “some” to “not all”. Contrary to the widely held assumption that scalar implicatures are highly regularized, frequent, and relatively context-independent, I will argue that they are in fact relatively infrequent and highly context-dependent; both the robustness and the speed with which scalar implicatures from “some” to “not all” are computed are modulated by the probabilistic support that the implicature receives from multiple contextual cues. I will present evidence that scalar implicatures are especially sensitive to the naturalness or expectedness of both scalar and non-scalar alternative utterances the speaker could have produced, but didn’t. In this context I will present a novel probabilistic and contextualist account of scalar implicature processing that has roots in both constraint-based and information-theoretic accounts of language processing and that provides a unified explanation for a) the varying robustness of scalar implicatures across different contexts, b) the varying speed of scalar implicatures across different contexts, and c) the speed and efficiency of communication.

LEC talk Wednesday 13 January: Florian Jaeger

By jon | January 6, 2016

NOTE UNUSUAL DAY AND LOCATION

Wednesday 13 January, 11:00–12:30
Room G32, 7 George Square

Florian Jaeger, University of Rochester (work with Dan Gildea, Masha Fedzechkina, Lissa Newport, and John Trueswell)

Pressures for processing and communicative efficiency bias language development

Functional biases have been hypothesized to affect language change and explain typological patterns. I’ll focus on two specific pressures on language processing and production that are well-established. The first pressure relates to the fact that linguistic communication takes place in the presence of noise, so listeners need to infer intended message from noisy input —making less probable message harder to infer (e.g., Levy, 2008; Norris & McQueen, 2008; Bicknell & Levy, 2012; Gibson et al., 2013; Kleinschmidt & Jaeger, 2015). The second pressure relates to memory demands during language processing, where longer dependencies are associated with slower processing (Gibson, 1998, 2000; Lewis et al., 2006; Vasishth & Lewis, 2005). Both pressures are well-known to affect language processing, including evidence from both experimental data (e.g., McDonald & Shillcock, 2003; Grodner & Gibson, 2005) and broad-coverage corpus studies (e.g., Demberg & Keller, 2008; Boston et al., 2010; Smith & Levy, 2013). This means that an ideal speaker (in the sense of ideal observers) should a) support low-probability —i.e., high information— messages with ‘better’ linguistic signals to the extent that this is warranted against the effort in implies (e.g., due to aiming for more precise articulations or due to articulation additional words, cf. Lindblom, 1990, Jaeger, 2006, 2013; Gibson et al., 2013) and b) aim for short dependencies (e.g., by reordering constituents, Hawkins, 2004, 2014).

Case study 1 asks whether actual natural languages have syntactic properties that increase processing efficiency, as would be expected if the processing efficiency biases language learning and/or change. Using data from five large syntactically annotated corpora, I show that natural languages have lower information density and shorter dependency lengths than expected by chance (Gildea & Jaeger, in prep; for dependency length, see also Gildea & Temperley, 2010). Previous work has found similar properties for phonological and lexical systems (e.g, Manin, 2006; Piantadosi et al., 2011, 2012; Wedel et al., 2013). The present work is the first to find that the same properties affect even the syntactic system (which involves considerably more complex latent structure and has often been assumed to be encapsulated from functional pressures).

Case studies 2 and 3 employ an miniature language learning approach to the same question. I show that learners of such languages restructure them in a way that improves both the inferability of messages and the dependency length (Fedzechkina et al., 2011, 2013, under review; Fedzechkina & Jaeger, 2015).Unlike approaches that rely on statistical modeling of typological data, miniature language learning does not suffer from data sparsity and can —if applied correctly— assess causality by directly manipulating the relevant factors.

Some references to related work from my lab, available at https://rochester.academia.edu/tiflo/Papers:

Fedzechkina, M., Chu, B., and Jaeger, T. F. submitted. ‘Long before short’ preference in a head-final artificial language: In support of dependency minimization accounts.
Fedzechkina, M., Newport, E., and Jaeger, T. F. accepted for publication. Balancing effort and information transmission during language acquisition: Evidence from word order and case-marking. Cognitive Science.
Fedzechkina, M., Jaeger, T. F., and Newport, E. 2012. Language learners restructure their input to facilitate efficient communication. Proceedings of the National Academy of Sciences 109(44), 17897-17902. [doi:10.1073/pnas.1215776109]
Gildea, D. and Jaeger, T. F. submitted. Language structure shaped by the brain: Human languages order information efficiently.

LEC talk Tuesday 15 December: Cathleen O'Grady

By jon | December 11, 2015

Tuesday 15 December, 11:00–12:30
Room 1.17, DSB

Cathleen O’Grady (work with Christian Kliesch, Kenny Smith, Thom Scott-Phillips)

The ease and extent of recursive mindreading

Mindreading, also called theory of mind, is the ability to mentally represent the mental states of other individuals, e.g. “Sarah believes in fairies.” Recursive mindreading is the ability to mentally represent mental states that themselves are representations of other mental states, e.g. “Joey knows that Monica thinks that Phoebe doesn’t know that Chandler and Monica love each other.”

Various accounts of pragmatics require not only that interlocutors are able to make inferences about each other’s mental states, but suggest that communicative intentions necessarily require recursive mindreading. However, despite a wealth of research on first-level mindreading and the developmental trajectory of mindreading, the extent of the adult human capacity for recursive mindreading is relatively under-studied. Existing research on the topic suggests that recursive mindreading is both limited and more effortful than other complex memory tasks, but this research suffers from substantial methodological flaws.

Based on the success in developmental studies of using implicit rather than explicit mindreading tasks, we present an implicit test of high levels of recursive mindreading. We show experimentally that adult human recursive mindreading abilities are more advanced than has previously been shown, with high accuracy up to seven levels of embedding. We further show that presentation of the task as implicit rather than explicit improves performance, explaining the difference in results from previous research, and suggesting that a more ecologically valid task is a more accurate test of recursive mindreading capacity. Our results lend support to pragmatic accounts requiring recursive mindreading.

LEC talk Tuesday 8 December: Marieke Schouwstra

By jon | December 3, 2015

Tuesday 8 December, 11:00–12:30
Room 1.17, DSB

Marieke Schouwstra (work with Kenny Smith and Simon Kirby)

From natural order to convention in silent gesture

Silent gesture, an experimental paradigm in which adult hearing participants describe events using only their hands, has been valuable for investigating the origins of word order. Goldin-Meadow et al. (2008) found a language-independent preference for SOV for extensional transitive events (e.g., boy-ball-throw), but participants prefer SVO for intensional events (e.g., boy-search-ball; Schouwstra & de Swart, 2014).

The SVO/SOV pattern for intensional/extensional events arises independently of participants’ native language, and, we will claim, represents naturalness, reflecting cognitive preferences to put Agents first (Jackendoff, 2002) and more abstract/relational information last. However, existing languages tend not to condition word order on event type and are instead more regular. Understanding this transition from naturalness to conventionalised regularity is a major goal of language evolution research. We present a new approach to this challenge using a novel experimental paradigm in which silent gesture is both used for communication (Christensen et al, 2015) and culturally transmitted through artificial generations of lab participants (Smith et al, in prep).

I will describe four experiments in which participants communicate about intensional and extensional events, either in a dyadic communication or a gradual turnover setup. Our experiments show that in silent gesture communication and transmission, semantically conditioned word order tends to disappear in favour of regular word order. The frequency of event types determines how regularisation progresses. This suggests that where pressures for naturalness and regularity are in conflict, languages start natural, but naturalness will give way to regularity as signalling becomes conventionalised through repeated usage.