Author: Andres Karjus

9 October: Zanna Clay

Vocal communication in our great ape relatives, the bonobos and chimpanzees: Insights into the evolution of language

Zanna Clay (Department of Psychology, Durham University)

Tuesday, 9 October, 11:00am -12:30pm
G.32 George Square

Our capacity for language is a central aspect of what it means to be human and sets us apart from the rest of the animal kingdom. Given that language does not fossilize, one way to understand how and when it first evolved is to examine the communicative capacities of our closest living relatives, the great apes. In this talk, I will review recent research that explores natural communication in our ours closest living relatives, the bonobos and the chimpanzees. I will primarily focus on what their natural vocal communication can tell us about their underlying social awareness and how this relates to the evolution of language. I report findings that highlight considerable communicative complexity, flexibility, and intentionality which, cumulatively, suggest that many of the building blocks for language are deeply rooted in our primate past.

25 September: Mora Maldonado

Priming semantic representations: An experimental approach to plurality

Mora Maldonado (Centre for Language Evolution, University of Edinburgh)

Tuesday 25 September, 11:30-12:30

G.32, 7 George Square

Sentences involving plural expressions can give rise to distributive and non-distributive interpretations (in (a) and (b) respectively):

(1) The girls ate two cookies.
(a) The girls ate two cookies each.
(b) The girls ate two cookies in total.

(2) The bags are light.
(a) The bags together are light.
(b) Each bag is individually light without the bags together being light.

In formal semantics, the derivation of these readings has been traditionally accounted for by assuming that non-distributive readings are obtained by default (as soon as the plural subject is in the predicate denotation), whereas distributive readings arise through the insertion of a covert distributivity operator D, whose meaning roughly corresponds to that of the word each in English (Link, 1987; Champollion, to appear). The D operator applies the VP to each atomic member of the plural subject.

While the availability of distributive and non-distributive readings for sentences in (1) and (2) is undisputed, one could ask whether the abstract mechanisms proposed to derive the contrast are accessed as such during sentence comprehension. I will report the results of three studies showing that non-distributive and distributive interpretations can be independently primed for both sentences in (1) and (2). Priming serves here to complement introspection on truth-value and inferential judgments, revealing the abstract mechanisms underlying semantic interpretation. Our findings suggest that the compositional operations proposed to derive the non-distributive/distributive contrast are at play during comprehension. The existence of distributive priming in absence of object covariation (e.g. 2) reveals an abstract representation of the non-distributive/distributive distinction, which is orthogonal to specific verification strategies.

18 September: Michael Franke

Listeners rationally adapt how they predictively process intonation when exposed to unreliable input

Michael Franke (Institute for Cognitive Science, University of Osnabrück)

Tuesday 18 September, 11:00-12:30

G.32, 7 George Square

Intonation plays an integral role in comprehending spoken language. It is also remarkably variable, often exhibiting only probabilistic mappings between form and function. Despite this apparent uncertainty, listeners can rapidly integrate intonational information to predictively map a given pitch accent onto the speaker’s likely referential intentions. We use manual response dynamics (mouse-tracking) to investigate two questions: (i) whether listeners draw predictive inferences from the presence and absence of an intonational marking and (ii) whether and how listeners adapt their online interpretation of intonational cues when these are reliable or stochastically unreliable. Our results are compatible with the assumption that comprehenders rapidly and rationally integrate all available intonational information, that they expect reliable intonational information initially, and that they adapt these initial expectations gradually during exposition to unreliable input. We explore the predictions of a Bayesian model of rational incremental belief update and observe a good fit to the empirical data.

21 August: Limor Raviv

Social structure affects the emergence of linguistic structure: experimental evidence

Limor Raviv (Max Planck Institute for Psycholinguistics)

Tuesday 21 August 2018, 11:00-12.30, DSB 1.17

Understanding world-wide patterns of language diversity has long been a goal for linguists, philosophers, and evolutionary scientists. Research over the past decade suggests that linguistic diversity may result from differences in the physical and social environments in which languages evolve. Specifically, it has been argued that larger population size, sparser network structure and higher proportion of adult L2 learners in the community lead to morphological simplification (e.g., Lupyan & Dale, 2010; Meir et al., 2012; Nettle, 2012; Trudgill, 2009; Wray & Grace, 2007). However, these three community properties are typically confounded in the real-world, making it hard to evaluate their unique contribution to this pattern of variation. In this talk I will present results from two group communication studies, in which we examine the live formation of new languages created in the lab by different micro-societies that differ in their size or in their network connectivity. This is the first experimental demonstration for the causal and independent role of community size and network structure in the emergence of linguistic structure. Additionally, I will present an outline for an upcoming study based on the same paradigm, which will test the role of second language learners in the community.

17 August: Shira Tal

Learning biases and language change: The effect of pragmatic factors on differential case marking

Shira Tal (Hebrew University of Jerusalem)

Friday 17 August 2018, 11:00-12.30, DSB 3.10

Many languages exhibit differential case marking (DCM), where marking targets only certain types of arguments. In such systems, atypical arguments (e.g., patients that are high on the animacy scale) are more likely to be marked. Recent work using artificial language learning experiments suggests that DCM is driven by a bias for efficient communication. For example, in a language with variable word order, case marking only animate objects prevents ambiguity in an efficient way, since marking is restricted to events that are potentially ambiguous (e.g., events with two animate participants). However, an alternative account suggests that DCM instead reflects the pragmatics of discourse. Agents of transitive sentences tend to be discursively old (given) while patients tend to be new. Atypical discourse associations (i.e., new agents or given objects) are often marked with additional linguistic material. For instance, in Catalan, only given objects are case marked. Marking of atypical associations between argument structure and information structure–rather than ambiguity avoidance–has therefore been argued to be the main source of DCM. Here, in two experiments, we test whether discourse status drives case marking during learning of an artificial language. In the first experiment the language has flexible word order whereas in the second experiment it has a fixed word order. Our results suggest a larger impact on word order than on case marking. We relate these findings to historical accounts of development of DCM.

03 July: Carmen Saldana and Jenny Culbertson

Do cross-linguistic patterns of morpheme order reflect a cognitive bias? 

Carmen Saldana and Jenny Culbertson (University of Edinburgh)

Tuesday 03 July 2018, 11:30–12.30
DSB 3.10
In this study we use Artificial Language Learning techniques (e.g., Culbertson & Adger, 2014) to test a hypothesized link between cognitive biases active during language learning and morpheme order cross-linguistic regularities; in particular, we investigate the tendency for number morphemes (e.g., singular or plural markers) to be ordered closer to the noun stem than case morphemes (e.g., nominative or accusative markers) (Greenberg, 1963, Universal 39). We hypothesize that this universal tendency might be driven by learners’ biases towards orders that match semantic scope relationships (Bybee, 1985; Rice, 2000). Across a series of experiments, we taught English-native participants an artificial language with noun stems, and case and number morphemes. Crucially, the input language indicated only that each morphemes preceded or followed noun stems; examples in which the two morphemes co-occurred were held out—i.e., no instances of plural accusatives. At test, participants were asked to produce utterances, including the held-out examples. We find that learners consistently produce number morphology closer to the noun stem than case. We replicate this basic effect with free and bound morphemes, and when case markers are higher frequency. However, we are able to reverse the preference to some degree by strengthening the relationship between nouns and particular case markers. Taken together, our results provide evidence of a cognitive bias towards scope-isomorphic patterns which may play a causal role in this strong typological generalization.

26 June: Laura de Rooij

Cultural transmission in an iterated learning task: the effect of animated motion on language structure

Laura de Rooij (University of Edinburgh)

Tuesday 26 June 2018, 11:30–12.30
DSB 1.20
Research by Kirby, Cornish, & Smith (2008) has demonstrated that compositional structure can evolve in the laboratory over repeated transmission in an iterated learning paradigm. Reanalysis of their data by Beckner, Pierrehumbert, & Hay (2017) indicates that the semantic dimension motion lead the way in the development of compositional structure. Beckner et al. suggested this be evidence for a cognitive bias involving particular attention to motion. However, motion in Kirby et al. was represented abstractly with arrows, which therefore may have been interpreted as part of the shape, rather than actual (animated) movement. The current study investigates the emergence of compositional structure for the semantic dimensions shape, color, and animated motion, encompassing seven chains in two experiment versions. We found that not motion exerted most influence on novel language creation, but that the shape dimension did. That is, structured mappings between meanings and forms developed more strongly for shape than for color or motion. Implications of these results will be discussed.

19 June: Fausto Carcassi

The evolution of adjectival monotonicity

Fausto Carcassi (University of Edinburgh)

Tuesday 19 June 2018, 11:30–12.30
DSB 3.10
Gärdenfors (2004) presents a generalization about the meaning of nouns, namely that nominal meanings can be represented as convex extensions on conceptual spaces. Carr et al (2017) argue that convexity emerges during language evolution from competing pressures for simplicity and informativeness. We first present a new pattern in the semantic structure of gradable adjectives, which we call monotonicity. We then propose that monotonicity, like convexity, emerges as a response to pressures for simplicity and informativeness but that, unlike convexity, human pragmatic skills play a crucial role in its evolution. We develop a computational model to support this proposal (and, time allowing and considering the recent shift of CLE talks from proper talks to slightly more informal occasions for feedback, also present a yet-unrealized experimental design for feedback).

22 May: Marieke Woensdregt

A model of cultural co-evolution of language and perspective-taking

Marieke Woensdregt (University of Edinburgh)

Tuesday 22 May 2018, 11:00–12:30
G32, 7 George Square

Language relies on mindreading (a.k.a. theory of mind), as language users have to entertain and recognise communicative intentions. Mindreading abilities in turn profit from language, as language provides a means for expressing mental states explicitly, and for transmitting one’s understanding of minds to others (e.g. younger members of the population). Given this interdependence, it has been hypothesised that language and mindreading have co-evolved. I will present an agent-based model to formalise this hypothesis, which combines referential signalling with perspective-taking. In this model, agents’ communicative behaviour is probabilistically determined by an interplay between their language and their perspective on the world. In order to learn the language, learners thus have to simultaneously infer both the language and the perspective of the speaker they’re receiving input from (using Bayesian inference). Simulation results show that learners can solve this task by bootstrapping one from the other, but only if the speaker uses a language that is at least somewhat informative.
The question then becomes under what circumstances a population of these agents can evolve such an informative language from scratch. We explore two different selection pressures: a pressure for successful communication and a pressure for accurate perspective-inference. We also compare two different types of agents: literal communicators and pragmatic communicators. Pragmatic speakers optimise their communication behaviour by maximising the probability that their interlocutor will interpret their signals correctly, given their model of the interlocutor’s language and perspective. Iterated learning results show that literal agents can evolve meaningful linguistic conventions both under a pressure for communication and under a pressure on perspective-inference. The same results were found for pragmatic agents, except that pragmatic agents can achieve equally high levels of success at communicating and inferring perspectives with much more ambiguous languages, because these agents can compensate for suboptimal languages using their pragmatic ability. Time permitting, I will also present some preliminary results on the evolvability of this pragmatic ability.