27 March: EvoLang dry-runs by Molly Flaherty & Marieke Schouwstra and Christine Cuskley

23 March 2018  •  Svenja Wagner

Alien symbols for alien language: iterated learning in a unique, novel signal space

Christine Cuskley (University of Edinburgh)

Tuesday 27 March 2018, 11:00–12:30
G32, 7 George Square

Studies in iterated learning of artificial ‘alien’ languages show that structure in language can arise from the process of cultural transmission (Kirby, Cornish, & Smith, 2008). Structure can accumulate not only in iterated artificial language learning (ALL) tasks, but also in iterated sequence learning tasks which are not explicitly linguistic (e.g., they contain no meanings, and do not use linguistic stimuli). Meaningless sequences of colours become more structured and more learnable over time (Cornish, Smith, & Kirby, 2013), reproduction of rhythmic sequences results in increased structure, learnability, and emergence of ‘musical universals’ (Ravignani, Delgado, & Kirby, 2016), and transmission of slide whistles can result increased structure (Verhoef, Kirby, & Boer, 2014). Where signals are mapped onto meanings, the relationships between these two spaces can have significant effects on the resulting structure (Little, Erylmaz, & Boer, 2017). While the signals and modalities with which iterated learning studies are conducted have expanded considerably in recent years, how properties of signal spaces interact with biases of learners in the emergence of structure is relatively under-studied.

To further investigate the effect of signal space on the evolution of structure and learnability, we used a completely novel set of graphical symbols called Ferros: a set of 137 abstract graphemes created using ferrofluid ink and visually unlike e.g., Roman orthography. To articulate in Ferro, participants move in a virtual two dimensional palette which produces a different symbol de- pending on their location within a square. The space is structured along two axes corresponding to the number of contours and nodes in each Ferro. Much like the phonetic space of consonants, distance between Ferros encodes similarity, but the forms are discrete. Ferros are signals which are entirely foreign to participants, who have to learn not only to use the apparatus which produces Ferros, but also what the relevant features of Ferros are.

The Ferro palette was used in an iterated sequence copying task involving hundreds of participants: each participant had three minutes to copy as many 3- character Ferro sequences as they could. Each sequence faded slowly after presentation, providing an additional pressure for quick reproduction. Participants were confined to producing three characters (i.e., sequences could not vary in length), and were provided with feedback on accuracy at each trial.

The initial sequences were pseudo-random, consisting of graphemes with ei- ther large articulation spaces in the palette or small, specific articulation spaces. Overall, 672 sequences were produced across 76 chains, each chain being be- tween 5 and 10 generations. Reproduction error was measured as mean Euclidean distance in the palette from the target sequence to the produced sequence, and ex- amined using a linear mixed effects model with generation and articulation space size as fixed effects.

Inclusion of generation and articulation space size improved the model fit sig- nificantly over a null model (χ2 = 4.53, p = 0.03). Error was higher overall in chains which started with small articulation spaces (β = 0.1, SE= 0.04, t = 2.5), indicating that participants found these harder to reproduce. Error decreased over generations in the small articulation space condition (β = -0.018, SE = 0.006, t = −3.035), but there was no such effect of generation for sequences which started with large articulation spaces.

Error decreased despite an overall retention of high sequence entropy: in other words, most sequences retained three different characters throughout a chain. The size of the area of the articulation space of a particular Ferro grapheme was sig- nificantly correlated with copying accuracy, and sequences in small articulation chains moved towards the larger articulation spaces over time, suggesting that larger articulation spaces make for greater ease of articulation.

The current study shows transmission can lead to increased learnability even in a completely novel signal system that participants have to learn from scratch in the process of transmission. In this case, the biases which drive increased learnability seem to derive primarily from the shape of the signal space: articulation area of a particular Ferro correlates significantly with its learnability (operationalised as reproduction error), and sequences gravitated towards larger articulation spaces over ‘time’. The shape of the space was perhaps especially influential in the cur- rent task because participants had no prior experience with Ferros, and so had fewer (or less influential) prior biases relative to other iterated learning tasks, par- ticularly those that utilise non-words and leverage existing linguistic knowledge. This has potential implications for the co-evolution of language and speech: con- straints of the signal space may be more influential in early stages of emergence as ‘speakers’ are not only reproducing utterances, but also learning how to ma- nipulate a novel signal space. This study shows that the Ferro palette has broad applications in language evolution research as a system of truly ‘alien’ symbols to study ‘alien’ language learning, emergence, and evolution.


Do we see word order patterns from silent gesture studies in a new natural language?

Molly Flaherty & Marieke Schouwstra (University of Edinburgh) (joint paper with Susan Goldin-Meadow)

Tuesday 27 March 2018, 11:00–12:30
G32, 7 George Square

Typological analysis clearly shows that the world’s languages are not evenly distributed among all logically possible patterns. Of the six possible orderings of Subject (S), Object (O), and Verb (V), SOV and SVO orders are vastly overrepresented in the world’s languages. Studies on the emergence of word order regularities in silent gesture by hearing non-signers (e.g., Goldin- Meadow, et al., 2008; Gibson et al., 2013) overwhelmingly find evidence for SOV ordering. Based on this type of evidence, it has been proposed that SOV ordering is the most basic ordering from which all other orders emerged. However, semantic properties of the meanings to be conveyed also influence word order in silent gesture. For instance, for intensional events (in which the object is possibly non-existent or dependent on the action; e.g., ‘man thinks of guitar’, ‘woman builds house’) a cross-linguistic preference for SVO was found (Schouwstra & de Swart, 2014). Recent work finds that meaning-dependent word order patterns typical of silent gesture disappear under the influence of interaction (Christensen et al., 2016) and cultural transmission (Schouwstra et al., 2016), in favor of more consistent word order usage. However, in these studies, word order usage never becomes completely regular.

Here we investigate whether traces of the SOV/SVO pattern found in silent gesture can be observed in a new natural language: Nicaraguan Sign Language. This sign language, one of the youngest languages known to science, was born in the late 1970s with the founding of a new school for special education. Though instruction was in Spanish, students soon began to communicate with one another manually. As succeeding cohorts of students learn NSL, the language itself is changing rapidly. Though somewhat variable, NSL word order is strongly verb-final and predominantly SOV (Flaherty, 2014). However, these data are based exclusively on analysis of extensional events. If NSL word order is also influenced by semantic properties of the utterance’s intended meaning, we would expect to see deviation from this SOV patterning. Participants viewed a series of events depicting eight extensional events (i.e. woman pop bubble) and eight intensional events (i.e. woman blow bubble) involving the same object. Participants were asked to describe what they saw to a peer. Twenty-six NSL signers participated. All signers were exposed to NSL before age 7, upon school entry between the early 1980s and early 2000s.

When we analyzed SOV and SVO strings (which accounted for only 39% of strings with 1 verb and 2 arguments), we did not observe the pattern typical of silent gesture: SOV was dominant for both extensional and intensional events, and very few SVO strings were observed (13 total, 10 for intensional events). NSL’s preference for verb-finalness (Flaherty, 2014) may not have allowed the SVO pattern to emerge. However, NSL signers tend to provide more detail than silent gesturers. As a result, many NSL strings were longer than strings observed in silent gesture. When we took into account all strings (including those with several verbs) and asked whether the Object preceded or followed target the Verb, we found more utterances with VO sub-strings (as opposed to OV) for intensional events than for extensional events (Fig 1). A logit mixed effects regression (with event type as fixed effect and random effects for item and signer) confirmed that strings containing VO were uncommon for extensional events (β=-2.9, SE=0.40, p<0.001), but significantly more likely for intensional events (β=1.8, SE=0.45, p<0.001). Thus, objects of intensional verbs are more likely to follow those verbs than are objects of extensionals not only in silent gesture, but also in an emerging sign language.

In this study, we find evidence for lab-documented word order preferences in an emergent natural language: objects precede verbs for extensional events, but follow verbs for intensional events. However, this word order pattern is manifested differently in Nicaraguan Sign because it interacts with NSL’s language-internal constraint for verb finalness. A combination of lab and field-based methodologies made this finding possible: without laboratory results, we would not have looked at a wider semantic range of events in the field; without field data, we would not have discovered the interaction between VO ordering preference and existing natural language constraints.

9 March: Vanessa Ferdinand

7 March 2018  •  Svenja Wagner

On the cultural evolution of public and private replicators

Vanessa Ferdinand (Santa Fe Institute)

Friday 9 March 2018, 12:00–13:30
3.01, 21 Buccleuch Place

When we replicate cultural artifacts, we transform them. But we are also selective when choosing which artifacts to copy in the first place. In this talk, I will discuss the California and Paris schools of cultural evolution as compatible descriptions of evolutionary processes acting on public and private representations, respectively. First, using a unique corpus of digital image evolution, I will show how public and private selection processes co-determine the evolution of image complexity in this system. These results demonstrate that public and private selection processes are both required for a full understanding of the evolution of cultural artifacts. Second, in a novel model of Bayesian cultural evolution, I will explore how the mappings between public and private representations determine the co-evolutionary dynamics of these two classes of replicators (i.e. data and hypotheses). This model provides a richer set of dynamics than those found in existing models of cultural evolution where public representations adapt to fixed private representations. Both of these projects highlight culture as a special evolutionary system that is composed of two classes of replicators (following Sperber, 1996): public structures in the world, such as artifacts and behaviors, and private structures in the mind, such as brain states and grammars.

30 January: Marieke Schouwstra

Improvisation and semantic biases: silent gesture goes cross-modal

(collaborative work with Katie Mudd, Ross Towns, and Simon Kirby)

Marieke Schouwstra (University of Edinburgh)

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

Silent gesture, a laboratory method in which naive participants improvise, using their hands and no speech to convey information, has been taken up as a way to investigate cognitive preferences for constituent ordering when communication occurs in the absence of a conventional system. Recent years have seen a steady increase in silent gesture experiments, and the method has made it possible to observe semantic biases that might play a role in the emergence of conventional word order in human language. 
But can we draw any conclusions about general linguistic mechanisms, based on results from the gestural modality? Much silent gesture work is presented under the assumption that the results are (at least partly) modality-independent. However, recent work suggests that some word order patterns can only be explained by appealing to the gestural modality specifically.
I will present two studies that address the issue of modality dependence, one in which participants interpret silent gesture strings, and one in which participants improvise in the vocal modality. Together, the experiments show that different semantic biases interact differently with the affordances of the modality, and that at least some patterns occur independently of the modality (phew!).


23 January: Molly Flaherty

How Developing Minds Build a New Language: the Emergence of Nicaraguan Sign Language

Molly Flaherty (University of Edinburgh)

Tuesday 23 January 2018, 11:00–12:30
G32, 7 George Square

This is a dry run for my job talk at UCSB for their job in “First Language Learning.” In this talk, I will give an overview of my research investigating the interaction between language input and the developing mind. I will closely examine a case of atypical first language learning: that of deaf children learning and creating a new language in Nicaragua. In this presentation, I will explore how the same forces at work in typical child language learning also build language structure when typical language input is not available. I use a range of methods and tools to explore the relative contributions of language input, language learning, and community interaction in building Nicaragua Sign Language (NSL). I will begin by discussing the growth of syntactic structure in homesign (manual communication systems created by isolated deaf individuals) and NSL by tracking the emergence of devices to mark argument structure. I find that the emergence of argument structure marking is neither instantaneous nor monolithic: some devices can be created by individual learners: homesigners and NSL signers of all generations employ these devices. Other markers show up only later with the addition of the language community and iterated transmission/learning of the language system. Next, I will turn to the emergence of structure at the morphological level and ask whether NSL signers have introduced overt marking of the morphological categories of noun and verb. I find that this distinction grows gradually: it appears in early Nicaraguan Sign Language and even in homesign, but increases in frequency as generations of children learn and pass down the language. Additionally, I will describe the gestural raw materials to Nicaraguan homesign and sign, and examine whether the gesture-rich communicative culture in Nicaragua may have been a particularly fertile environment in which to grow a new language. Finally, I investigate the cognitive consequences of not learning a mature language in childhood. I will present results indicating that in the domain of numerical cognition, individuals who do not learn number words, even if they are immersed in a world full of number, are unable to track exact quantity above five. In conclusion, I will show that the shape of language derives from human learning and use, and that one’s specific childhood language environment can have lifelong cognitive consequences.

5 December: Jennifer Culbertson

Children’s sensitivity to phonological and semantic cues during noun class learning: evidence for a phonological bias

Jennifer Culbertson (University of Edinburgh)

Tuesday 5 December 2017, 11:00–12:30
1.17 Dugald Stewart Building

Previous research on natural language acquisition of noun classification systems, such as grammatical gender, has shown that child learners appear to rely disproportionately on phonological cues (e.g., Gagliardi & Lidz, 2014; Karmiloff-Smith, 1981). Surprisingly, this occurs even when competing semantic cues are more reliable predictors of class. Culbertson, Gagliardi & Smith (2017) present evidence from artificial language learning experiments with adults suggesting that the over-reliance on phonology may be due to the fact that phonological cues are generally available earlier than semantic cues; learners acquire early representations of phonological dependencies (e.g., between a gendered determiner and a noun) before acquiring the semantic referents of nouns. In other words, Culbertson et al. (2017) suggest there is no a priori bias in favor of phonological cues to noun class. In this talk, I will present follow-up work investigating whether our results hold for child learners. In a series of experiments, we show that two cues–one semantic and one phonological–which children are equally sensitive to in isolation, are in fact treated differently when they are in conflict. In particular, unlike adults, children prioritize phonological cues regardless of when cues are available. This suggests the possibility that children are in fact biased to attend to phonological cues when acquiring noun classification systems.

21 November: Fiona Kirton

Visual saliency and word order in improvised gesture

Fiona Kirton (University of Edinburgh)

Tuesday 21 November 2017, 11:00–12:30
G32, 7 George Square

A commonly cited observation is that the distribution of the basic word orders across the world’s languages is highly non-uniform. Although all six possible orders are attested, around 88% of languages with a dominant order use either SOV or SVO. In recent years there has been increasing interest in the improvised gesture paradigm as a way of investigating this asymmetry. In one of the earliest studies of this kind Goldin-Meadow et al. (2008) argued that SOV is the default order used in developing communication systems and suggested that other orders emerge later in response to some pressure or combination of pressures. More recent studies suggest a more complex picture: SOV is the default order only for certain types of event and structural choices in improvised gesture are influenced by properties of the participating entities and actions and/or the relations between them. In a recently published study, Meir et al. (2017) argue that saliency is a key determiner of constituent order in improvised gesture such that more salient entities, typically human agents, tend to be mentioned first.

In this talk, I will present an improvised gesture study that investigates the role of saliency in more detail. Results from this study suggest that manipulating the visual saliency of the Agent influences the relative order of the Patient and the Action. I will propose that the relative visual saliency of the Agent and the Patient affects the way participants mentally construe events, which in turn determines their choice of constituent order.

14 November: Inbal Arnon

More than words: developmental and psycholinguistic investigations of the building blocks of language

Inbal Arnon (Hebrew University of Jerusalem) 

Tuesday 14 November 2017, 11:00–12:30
G32, 7 George Square

Why are children better language learners than adults despite being worse at a range of other cognitive tasks? Many accounts focus on the cognitive or neurological differences between children and adults. Here, I focus on the way prior knowledge impacts the building blocks children and adults use. I explore the role of multiword sequences in explaining L1–L2 differences in learning and language use more generally to argue that children are more likely than adults to rely on them in learning. While words are often seen as the basic building blocks of language (e.g., Pinker, 1991), there is  growing theoretical interest and empirical evidence for the role of multiword units in language. I draw on developmental, psycholinguistic and computational findings to show that children use multiword units in learning; that such units are facilitative for learning certain grammatical relations; and that adult learners rely on them less, a pattern that can explain some of the differences between child and adult language learning. I will then present findings on the emergence of structure in child and adult learners and discuss implications for models of L1 and L2 learning.

7 November: Christine Cuskley

Gamifying language evolution

Christine Cuskley (University of Edinburgh)

Tuesday 7 November, 11:00 – 12:30
G32, 7 George Square
At the heart of language are shared conventions: from the rules that we use and how we inflect them, to the vast lexicon we use to describe the world, language works because conventions are shared across a population of speakers. Thus, a crucial question for language evolution is how we come to have shared conventions: how these emerge, how they change over time, and how they decline. In this talk, I will present some early studies of a novel virtual signal modality called Ferro, which allows for truly “alien” artificial language learning. Early results suggest that while Ferro are difficult to learn, they share some interesting features with linguistic articulation spaces which may have strong effects on learning biases. The end goal of the Ferro palette is multi-player game called FerroCell, which will allow us to see conventions emerging and evolving in player populations with realistic interaction networks. I’ll outline what FerroCell will look like, and what we hope to learn in the first “petri-dish” experimental game in language evolution.


31 October: Jon Carr

Simplicity priors and conceptual structure

Jon Carr (University of Edinburgh)

Tuesday 31 October 2017, 11:00–12:30
G32, 7 George Square

Languages are shaped by competing pressures from learning and communication. Learning favours simple languages, while communication favours informative ones, giving rise to the simplicity–informativeness tradeoff.

In this talk I will pay special attention to the simplicity part of this tradeoff. I argue that learning is best viewed as a model selection problem in which a simplicity prior plays an essential role in allowing agents to reason about unseen items and to avoid overfitting noise in the data stream.

I show that simple, structured, learnable concepts can emerge from this very general principle in a Bayesian iterated learning model. And I show that an experimental analogue of this model returns strikingly similar results.

Finally, I consider another hypothesis that could explain the results – that learners have a prior bias for informativeness – and I show why this explanation is unlikely.

17 October: Alexander Martin

Biases in phonological processing and learning

Alexander Martin (University of Edinburgh)

Tuesday 17 October 2017, 11:00–12:30
G32 7 George Square

During speech perception, listeners are biased by a great number of factors, including cognitive limitations such as memory and attention and linguistic limitations such as their native language. In this talk, I will present my PhD work addressing two of these factors: processing bias during word recognition, and learning bias during the transmission process. These factors are combinatorial and can, over time, affect the way languages evolve. First, I will detail a study focusing on the importance of phonological features in word recognition, at both the perceptual and lexical levels, and discuss how speakers integrate information from these different sources. Second, I will present a series of experiments addressing the question of learning bias and its implications for the linguistic typology. Specifically, I will present artificial language learning experiments showing better learning of the typologically common pattern of vowel harmony compared to the exceedingly rare, but logically equivalent pattern of vowel disharmony. I will also present a simple simulation of the transmission of these patterns over time, showing better survival of harmonic patterns compared to disharmonic ones.