Title: Brain-to-brain coupling during dialogue: What sentence fragments can reveal about 'joint' mental representations
Funder: Economic and Social Research Council

Abstract: Talking to one another is one of the cornerstones and joys of human experience. Imagine how difficult our lives would be if we couldn't use language to communicate, have a conversation, ask questions or easily say what we mean. But actually, we might not even have to say or pronounce all the things that are meant or understood in a conversation (full meanings shown for the reader in brackets): A: Someone called for you. B: [Did someone] Really [call for me]? A: Yes, [someone] really [called for you]. B: Who [called for me]? A: John [called for you]. B: About what [did John call]? Everyday interaction would be completely different if we had to repeat all the information we mean and understand, word for word, during dialogue - it would sure take a lot longer to get anywhere. Although we are not aware of it, most conversation is reduced or simplified into sentence fragments that "stand in" for full formal linguistic structure. Nonetheless, without being pronounced, complex structure is easily understood by both people. This fact clashes with a defining property of human language - a formal correspondence between sound and meaning, and seems to challenge the rules we use to combine linguistic units into larger ones. These seemingly innocuous sentence fragments may be why dialogue is such an easy, effective form of communication. Fragments naturally tap into information exchange during dialogue because they require speakers and listeners to refer to and access a shared memory of what has been said. But how do we form and update this shared memory? Speakers must formulate utterances with the mental states of addressees in mind. The reduced fragments people end up producing and hearing operate as a natural "compression algorithm", making conversation easy and productive most of the time. But how can dialogue be so fragmented without people losing the plot more often? It may well be that aspects of linguistic structures and human memory allow people to 'jointly' activate information, or align their dialogue. In current theory, people align via priming, or passive activation of mental representations between speakers - which is why people often repeat each other's words and phrases. What is rarely noted is how, in order to converse, speaker and listener have to tacitly 'agree on' material that is not overtly expressed, as in the brackets above. A series of experiments investigates how fragments are represented and transmitted between speakers, and whether the brain treats externally-sourced representations the same as internally-generated ones during dialogue. A second line of research develops an innovative new method that can index the 'flow' of information between speakers' brains during spontaneous, unscripted dialogue. Humans are fundamentally interactive - a fact only recently impacting theories of human cognition, highlighting the necessity of understanding classic cognitive questions in terms of an interaction between two actors in an environment. The basic notion is that real-time interaction, such as dialogue, is made possible by brain-to-brain coupling; where one brain's perceptual system is coupled to another brain's motor or speech output, deriving from a related ability of brains to bind to exogenous environmental signals. These signals, including those emanating from other brains, e.g., speech, are converted into internal signals the brain uses to infer, in turn, about its environment. A brain-to-brain coupling approach for dialogue requires methodological innovation in language research: we need to observe brain activity from two people interacting in real time. My research combines methods and theories from distinct domains of psychology and cognitive neuroscience to develop a novel paradigm for studying real-time interactive dialogue. This funding, if awarded, would allow me to develop my skill set to a degree that I would otherwise not be able to, adding value to my academic training and growth.


Research activity codes: 1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING;1.2 PSYCHOLOGICAL AND SOCIOECONOMIC PROCESSES
Health categories: MENTAL HEALTH;NEUROLOGICAL