We introduce an experimental paradigm for studying the cumulative cultural evolution of language. In doing so we provide the first experimental validation for the idea that cultural transmission can lead to the appearance of design without a designer. Our experiments involve the iterated learning of artificial languages by human participants. We show that languages transmitted culturally evolve in such a way as to maximize their own transmissibility: over time, the languages in our experiments become easier to learn and increasingly structured. Furthermore, this structure emerges purely as a consequence of the transmission of language over generations, without any intentional design on the part of individual language learners. Previous computational and mathematical models suggest that iterated learning provides an explanation for the structure of human language and link particular aspects of linguistic structure with particular constraints acting on language during its transmission. The experimental work presented here shows that the predictions of these models, and models of cultural evolution more generally, can be tested in the laboratory.cultural transmission ͉ iterated learning ͉ language evolution T he emergence of human language has been cited by Maynard Smith and Szathmary (1) as the most recent of a small number of highly significant evolutionary transitions in the history of life on earth. The reason they give for including language in this list is that language enables an entirely new system for information transmission: human culture. Language is unique in being a system that supports unlimited heredity of cultural information, allowing our species to develop a unique kind of open-ended adaptability.Although this feature of language as a carrier of cultural information obviously is important, we have argued that there is a second sense in which language is an evolutionary milestone: each utterance has a dual purpose, carrying semantic content but also conveying information about its own construction (2-5). Upon hearing a sentence, a language learner uses the structure of that sentence to make new inferences about the language that produced it. This process allows learners to reverse-engineer the language of their speech community from the utterances they hear. Language thus is both a conveyer of cultural information (in Maynard Smith and Szathmary's sense) and is itself culturally transmitted. This cultural transmission makes language an evolutionary system in its own right (2-3), suggesting another approach to the explanation of linguistic structure. Crucially, language also represents an excellent test domain for theories of cultural evolution in general, because the acquisition and processing of language are relatively well understood, and because language has an interesting, nontrivial, but well documented structure. § During the past 10 years a wide range of computational and mathematical models have looked at a particular kind of cultural evolution termed ''iterated learning'' (4-13).Iterated ...

Language exhibits striking systematic structure. Words are composed of combinations of reusable sounds, and those words in turn are combined to form complex sentences. These properties make language unique among natural communication systems and enable our species to convey an open-ended set of messages. We provide a cultural evolutionary account of the origins of this structure. We show, using simulations of rational learners and laboratory experiments, that structure arises from a trade-off between pressures for compressibility (imposed during learning) and expressivity (imposed during communication). We further demonstrate that the relative strength of these two pressures can be varied in different social contexts, leading to novel predictions about the emergence of structured behaviour in the wild.

Language maps signals onto meanings through the use of two distinct types of structure. First, the space of meanings is discretized into categories that are shared by all users of the language. Second, the signals employed by the language are compositional: The meaning of the whole is a function of its parts and the way in which those parts are combined. In three iterated learning experiments using a vast, continuous, open‐ended meaning space, we explore the conditions under which both structured categories and structured signals emerge ex nihilo. While previous experiments have been limited to either categorical structure in meanings or compositional structure in signals, these experiments demonstrate that when the meaning space lacks clear preexisting boundaries, more subtle morphological structure that lacks straightforward compositionality—as found in natural languages—may evolve as a solution to joint pressures from learning and communication.

Cruice, M. (2013) A "novel" reading therapy programme for reading difficulties after a subarachnoid haemorrhage. Aphasiology A "novel" reading therapy programme for reading difficulties after a subarachnoid haemorrhage ABSTRACT Background: Although several treatments for acquired reading difficulties exist, few studies have explored the effectiveness of treatment for mild reading difficulties and treatment for reading difficulties associated with cognitive impairment. Aims: This study explored the effectiveness of an individual strategy-based reading treatment of 11 sessions given to a female participant (IW) who had mild reading difficulties following a subarachnoid haemorrhage (SAH). The impact of treatment on reading ability, confidence and emotions associated with reading were investigated. Methods & Procedures: Treatment focussed on the use of strategies to support IW's memory when reading books, the use of a checklist to select appropriate reading materials, and increasing IW's confidence in discussing the book she was reading with others. A person-centred approach and personally relevant materials were used throughout the treatment. Reading ability was assessed using the Gray Oral Reading Tests (GORT-4; Lee Wiederholt & Bryant, 2001), and IW's perspective was obtained using the Reading Confidence and Emotions Questionnaire (RCEQ; see Cocks et al., 2010). Pre-treatment, post-treatment and maintenance (7 weeks post) assessments were undertaken, with an additional exit interview at the final time point. Outcomes & Results: Gains were noted in reading rate, accuracy, comprehension, and confidence, with parallel increased pleasure gained from reading and reduced negative emotions and frustration. Self-reported gains included conversing with 3 Author's final draft of Cocks, N., Pritchard, M., Cornish, H., Thompson, N., & Cruice, M. (2013) A "novel" reading therapy programme for reading difficulties after a subarachnoid haemorrhage. Aphasiology others about material read, verbal communication, and re-engagement with the identity of being a reader. Conclusions: Strategy-based treatment resulted in positive gains in reading for pleasure, conversation, and identity, for an individual with mild chronic reading difficulties. Participant self-report and interview reveal the true value of this treatment for the individual. The positive results suggest that further research is warranted that investigates the effectiveness of strategy-based reading therapy approaches for others with acquired reading difficulties. MAIN TEXT While text-level reading difficulties are common after stroke and head injury, most reading therapy protocols that have been published have focused on reading single words (e.g., Beeson, Rising, Kim, & Rapcsak, 2010; Nickels, 1992). While these may be appropriate for clients who have more severe difficulties, or difficulties with specific aspects of reading e.g. grapheme-to-phoneme conversion, they are not appropriate for clients who have more mild reading difficulties associated with an underlying cogn...

Human language is composed of sequences of reusable elements. The origins of the sequential structure of language is a hotly debated topic in evolutionary linguistics. In this paper, we show that sets of sequences with language-like statistical properties can emerge from a process of cultural evolution under pressure from chunk-based memory constraints. We employ a novel experimental task that is non-linguistic and non-communicative in nature, in which participants are trained on and later asked to recall a set of sequences one-by-one. Recalled sequences from one participant become training data for the next participant. In this way, we simulate cultural evolution in the laboratory. Our results show a cumulative increase in structure, and by comparing this structure to data from existing linguistic corpora, we demonstrate a close parallel between the sets of sequences that emerge in our experiment and those seen in natural language.