Scientific studies of human communication

Humans effortlessly share their immediate thoughts with other human minds, but it remains a mystery how. A common language certainly helps but we know that it is not necessary for communication, as we also understand tourists and infants who speak a different language or no language at all. In fact, research shows we can instantly build new ways to communicate if we need to, but how we achieve this extraordinary feat is largely an open question. Our understanding may be limited because the open-ended and interpersonal nature of human communication has been largely overlooked or simply out of reach of controlled scientific experiments. The below snapshots and suggested readings represent a selection of studies that have taken up this challenge. This list is not exhaustive but meant to provide a glimpse of the history and status quo of this inter-disciplinary research theme at the roots of human sociality. The list also includes recent neuroscientific and clinical observations on (experimentally-controlled) communicative interaction. Together, this work is suggesting that people in dialogue understand one another because they continuously develop and coordinate a shared cognitive space that provides critical context for using and interpreting communicative messages (Stolk, Verhagen & Toni, 2016). Our international team aims to understand how this fleeting knowledge space is generated in our brains, and how its representation is altered in disorders of human communication.

Autistic individuals struggle to rapidly converge on a shared meaning for an utterance when meaning requires referencing the shared communicative context

This study causally tested the notion of a shared cognitive space underlying human communication in pairs of individuals on the autism spectrum (Wadge et al., Cortex 2019). Despite otherwise indistinguishable performance from neurotypical pairs, pairs containing autistic individuals had lower communicative success. This communicative impairment was predicted by their ability to rapidly align on the meaning of an utterance with their communication partners. This misalignment was greatest when meaning depended on the unique communicative context established through past interaction with their partners.

Brains become synchronized due to the accumulation of shared representations at a scale independent from individual utterances

Using two scanners, this neuroimaging study found that brain areas tracking mutual understanding over a series of interactions become synchronized due to the accumulation of shared representations (Stolk et al., PNAS 2014). This interpersonal synchrony occurred only when the pairs developed new shared representations, and at a temporal scale independent from individual communicative utterances. This observation suggests that the meaning of an utterance is not a property of the utterance itself. Rather, people in dialogue understand one another because they continuously keep their thoughts aligned with one another, forming a shared cognitive space that provides critical context for selecting and interpreting utterances.

Communicators and addressees achieve mutual understanding by using the same computational procedures and neuronal substrates

Using magnetoencephalography, this study found that the same right-hemisphere brain regions in communicators and addressees are already upregulated before a communicative utterance is generated or interpreted during social interaction (Stolk et al., PNAS 2013).

Interpreting indirectness engages overlapping brain networks across overhearers and addressees

Using a fictional job interview setting in the scanner, this study found that interpreting indirect, non-literal answers from interviewees activated brain regions inside as well as outside the language-dominant left hemisphere, including the right hemisphere and medial prefrontal structures, both when those answers were directed to them or to other interviewers (Bašnáková et al., 2015).

Children who spent an increased number of days in daycare may benefit from a greater exposure to social and communicative situations

The style in which five-year-olds tried to communicate changed depending on who the children thought their co-player was. When they thought they were playing with a two-year-old, they spent a great deal of time trying to patiently convey relevant game information. When they were told they were playing with a child their own age, their communication style was not as labored. The more days children spent in daycare, the more they adjusted their communication style, suggesting an important role for early social experience in the development of our interactional abilities (Stolk et al., PLoS One 2013).

Language processing depends on local principles of interaction

This study had pairs of adults describe locations within a predefined spatial network to help each other reach target locations. They could talk back and forth as much as they needed. The main findings are that, in referring to locations, different pairs converge on different descriptions for the same location. However, within the same pair, speakers adopt very similar forms of descriptions, a processed dubbed lexical entrainment. This entrainment is progressive, increasing as the dialogue proceeds, suggesting that dialogue partners coordinate to achieve a singl mutually satisfactory type of description  (Garrod & Anderson, Cognition 1987).

Referring as a collaborative process between speakers and listeners

This study had pairs of adults describe figures based on the ancient Chinese game of Tangram in order to achieve a target arrangement of those figures. They could talk back and forth as much as they needed. The study found that when speakers refer to an object, they are proposing a conceptualization of it, a proposal their addressees may or may not agree to. Once they do establish a shared conceptualization, dubbed a conceptual pact, they appeal to it in later references even when they could use simpler references. Over time, speakers simplify conceptual pacts and, when necessary, abandon them for new conceptualizations (Clark & Wilkes-Gibbs, Cognition 1986).

Communicative proficiency improves from kindergarten age onward

This study had pairs of children in kindergarten, 1st, 3rd and 5th grades play a communication game which required they develop names to refer to unique graphic figures, portrayed on a wooden block with a hole in it. They would receive these blocks one at a time from a dispenser. Then they described the figure to the listener, someone their own age, who then needed to infer and select the intended figure and block. After each description, both players stacked their blocks on a peg, and after each round the pegs were compared for overlap. Unlike older children, kindergartners did not improve their communication across interactions with the same partner, suggesting that age 5 represents a critical milestone in the development of our interactional abilities (Krauss & Glucksberg, Child Development 1969).

Suggested readings