'What do you think the girl wants from Father Christmas?' Theory of Mind research with deaf infants
11 May 2013
DCAL Deputy Director, Professor Gary Morgan, and other colleagues from DCAL and City University London have been working with researchers from the University of Sheffield, University of Trento and University of Gothenburg, on a joint project investigating early interaction involving British and Swedish hearing parents and their deaf and hearing 2-3 year old children. This research is the first to show that conversational input about mental states directed towards very young deaf children differs significantly in those areas of interaction thought to be crucial for Theory of Mind (ToM) development. ToM is the reasoning that enables us to reflect on the mental states of others. Importantly it contributes to sophisticated forms of human interaction and provides a basis for understanding others' actions and dispositions.
The project focused on "mental state conversations" and the quality of "conversational turns". The aim was to identify if there are differences in the way in which parents communicate with deaf children and with hearing children, and from this understand more about the possible effects of parent-child interaction on deaf children's social-cognitive development. Mental state language relates to cognition (e.g. "think", "know"), emotions (e.g. "happy", "worried", "bored"), and desires (e.g. "want", "like", "don't like", "hope"). Conversational turns refer to the way in which children and parents interact: how communication is initiated and connected, or alternatively, fails or is unclear.
With data from around 50 children, the research showed that there was a general lack of mental state conversations with the deaf children (e.g. questions like "what do you think the girl wants from Father Christmas?" when looking at a picture). In both the Swedish and British samples studied, parents of young hearing children used far more cognitive mental state language and their conversations were characterised by more effective turn-taking compared to parents of deaf children.
The research team suggests these differences in content and connectedness of interaction may contribute directly to the substantial delay in the expression of ToM reasoning that has been identified in older deaf children through other research projects.
Research by other groups has found that deaf children aged 4 years and above who come from hearing families where sign language is not used effectively display a protracted delay in the development of ToM reasoning. This delay does not extend to other areas of the children's cognitive development and is not found in deaf children from deaf families, who are exposed to a sign language from birth.
The research is especially important given that 90-95% of deaf children are born to hearing parents, the vast majority of whom have no, or only limited sign language skills. Meanwhile ToM in typically developing hearing children has also been linked to the importance of early learning through family conversational input about mental states before language is acquired. Other research work by the same group has suggested all infants have a core ToM understanding as indicated by their performance on tasks where the child's looking behavior is recorded rather than requiring an explicit response. The key issue concerns what input is required to trigger the expression of ToM.
The aim is that by examining conversational interaction between hearing parents and deaf infants this new research may help to identify the origins of subsequent ToM impairments in deaf children. One implication of the research is that early intervention for families with deaf children should include encouragement for parents to engage their young children in conversation about the mind, whether in spoken language or sign language.
- A full copy of the research paper Belief attribution in deaf and hearing infants. Meristo, M., Morgan, G., Geraci, A., Iozzi, L., Hjelmquist, E., Surian, L., & Siegal, M. (2012).