A couple of studies have combined iterated learning techniques with artificial language learning or communication game paradigms in a bid to explore how languages and other communication systems evolve through learning and use. In language evolution, iterated learning has become a paradigm which involves experimentation with artificial languages. Human participants learn a set of items in the language, and then produce linguistic behavior which subsequent individuals learn from and so on. This was introduced by researchers Kirby S, Cornish H, and Smith K. A learning bottleneck is also imposed on transmission: participants are asked to learn a target language based on exposure to a smaller set of language items from the original set of stimuli, with the language produced by the nth participant. In this chain, the nth participant provides the input to participant n +1 and so forth. In short, participants have access to only a limited set of data.
3.2.1. Literature on Laboratory Experiments with Humans
Many types of experiments relating to exploring the phenomenon of language evolution have been conducted in the laboratory. They are divided into experiments focusing on signal creation, the emergence of communication systems, and cultural transmission itself.
Signal Creation
Understanding the origins of language will involve the uncovering of the necessary cognitive capacities used for linguistic communication and detecting communication intentions. Studies on signal creation investigate how individuals recognise the communicative nature of certain behaviour, before even questioning how meaning is created from the signals. Scott-Phillips et al. (2009) ‘s embodied communication game (ECG) is a two-player game designed to serve this investigation. It requires participants to travel around a 2X2 grid with movement as their only communicative resource. This forces participants to find ways in revealing which movements are communicative in nature rather than acts of travel. The difficulty of this task revealed that common ground serves is especially key to the emergence of communication channels. Related work (as cited in Scott-Phillips & Kirby, 2010) also lead to similar conclusions. The challenge of these games is highlighted in the difficulty of communicating one’s communicative intent.
Emergence of communication systems
Once communicative intent is established, individuals now face the task of negotiating the forms and meanings of symbols to create a communication system. In a pioneer study done by Galantucci (2005), pairs of participants were tasked to invent and agree on a set of signs to use to solve a coordination problem. The study aimed to illustrate how human communication can be understood as a form of joint action. An example of a line of research that has been spawned from the pioneering studies on the role of interaction in the emergence of communication system is the use of graphical communication tasks. Such tasks are advantageous in its provision of a medium which allows the invention of new signs to be used in an interactive context. Examples of studies that illustrates this include those done by Garrod et al (2007, 2010).
Cultural transmission
Following the establishment of some sort of language, cultural transmission, which is an instance of iterated learning, takes place. In Kirby et al’s (2008) experiment, participants were asked to learn labels for coloured moving shapes, where the initial artificial language provided a randomly generated, unique label for the shapes. Their findings revealed a structured language that developed from the initial unstructured set of meaning-signal associations as a result of the iterated learning. By the 10th participant, each label had consisted of a prefix which specified colour (e.g. ne– for black, la– for blue), a stem for shape (e.g. –ho– for circle, -ki- for triangle) and an affix specifying motion (e.g. –plo for bouncing, –pilu for looping). As predicted by mathematical modelling results, languages developed over time to ones that facilitated generalisations and rules. Compositional languages also developed where components or sub-parts of each complex label or word specified components of the picture that the label had referred to.