When deaf children are not exposed to sign language they spontaneously develop novel forms of communication. In the laboratory, adults interacting in the absence of conventional means of communication also have a remarkable talent for developing novel forms of communication. Bruno Galantucci and his students at Yeshiva University use these observations to test a simple hypothesis about the core design principles of natural languages. At the most fundamental level, spoken languages rely on a few dozen basic forms. Sign languages, however, rely on a much larger number of basic forms. Signed and spoken languages also differ in another way: The forms of sign language can more easily mimic aspects of the world to which they refer than can the forms of speech. It may be that the two differences are intimately connected: The more the forms of a communication system mimic the world, the more likely it is that the system relies on a large set of basic forms. If correct, this provides a simple and elegant explanation for a core difference in design between spoken and signed languages.
This research will be carried out at Yeshiva University, a primarily undergraduate institution, and will provide excellent research experience for undergraduate students. The project also develops an innovative methodology which will be made readily available to other researchers through a dedicated website. Such methodology can be used for further investigations of the core mechanisms supporting human communication. Knowledge about these mechanisms has a number of potential applications. For example, it can be used (a) to design languages which facilitate universal communication over the internet; (b) to develop new technologies to help people who suffer from communication disorders; and (c) to improve the methods used for teaching foreign languages.
This project investigated the emergence of a basic property of human communication systems: combinatoriality (the combination of a small set of meaningless forms, known linguistically as phonemes, to create all the words of the language). English, for example, employs some forty phonemes to express an infinite number of meanings, while the Papua New Guinean language Rotokas is even more compact, using only eleven. Combinatoriality contributes to the efficiency of a communication system, because using a small set of forms that can be easily produced and perceived simplifies the task of transmitting messages through a noisy channel. (Morse Code exhibits this transmission efficiency to a particularly high degree, employing only two basic forms.) For a long time it was assumed that combinatoriality was a property of all human languages. However, recent research suggests that Al-Sayyid Bedouin Sign Language (ABSL), a relatively young language used in the Negev Desert of Israel, is not combinatorial. This may be because ABSL, unlike English, makes extensive use of mimesis — that is, forms in ABSL tend to resemble the things they refer to (their "referents"). Because of this strong link between form and referent, mimesis offers a very efficient way of establishing new signs. However, because mimetic forms resemble what they refer to, they cannot easily be reused for dissimilar referents without risk of confusion. In other words, while mimetic forms help establish reference, they are not well suited to combinatoriality. This suggests a simple hypothesis: that communication systems are likely to be more combinatorial where the opportunity for mimesis is restricted. Where mimesis is available, on the other hand, the support it offers for establishing new signs makes it likely to be adopted, leading to low levels of combinatoriality. There may be some support for this hypothesis to be found in other sign languages. The visual-manual modality exploited by sign languages offers far greater opportunities for mimesis than the oral-auditory modality exploited by speech, and sign languages seem generally to employ larger sets of basic forms than spoken languages. However, there is no clear consensus on how to count meaningless forms in sign language, and the existence of numerous other differences between spoken and signed languages raise serious problems for testing this hypothesis using real-world data. We therefore tested this hypothesis experimentally using an innovative methodology in which participants construct a novel communication system cooperatively in the laboratory. We manipulated the opportunity for mimesis and measured the combinatoriality of the communication systems that were created. In line with the hypothesis presented above we found that, where mimesis was available, it was overwhelmingly adopted as a strategy, and the resulting communication systems were significantly less combinatorial than those created without mimesis. We also found that mimesis made it much easier to construct a communication system, offering an insight into the way new languages are likely to emerge. This project employed novel experimental techniques to test a previously untested hypothesis concerning the fundamental design of human communication systems, which could not have been tested using data from existing languages. The project had a number of significant impacts. First, by contributing to our understanding of human communication, it may contribute to the development of new technologies to help people suffering from communication disorders, to improving the methods used for teaching foreign languages, and even designing new languages for facilitating universal communication. Second, the project produced datasets and software that we have made freely available and can be used in other research projects. Third, the project contributed an experimental framework that can be adapted to other questions concerning human communication, opening new opportunities for researchers in the field. Fourth, the project provided substantial training to a postdoctoral research fellow, preparing him for a successful scientific career. Finally, the project has allowed a number of undergraduate students to participate directly in cutting-edge research and gain experience that will help them (and has already helped some of them) to be employed as researchers and join graduate programs in science.
