Culture-Specificity and Generalisability of Factors That Affect Vocal Modulation during Conversation: The Role of Autistic Traits

Background:

Vocal modulation is a critical component of interpersonal communication. It not only serves as a dynamic and flexible tool for self-expression and linguistic information but also functions as a social tool. Autism Spectrum Disorders is often associated with a lack of appropriate vocal modulation, with several reports of a ‘monotonic’ style of speaking. Vocal modulation can also be affected by the relationship between the two interactants, such as interpersonal closeness. We speak differently with our friends vs strangers. Cultures across the world are associated with established differences in display rules for facial and vocal expressions. The extent of culture-specificity in the impact of these factors on vocal modulation remains largely unknown, and can contribute to differential manifestation of autism-related symptoms.

Objectives:

To investigate the impact of autistic traits and interpersonal closeness on vocal modulation during a real two-person conversation, in three countries (India, UK, and Italy).

Methods:

85 same-sex pairs of participants were tested in all, by being recorded during a conversation about an abstract painting. The articulation area of the speech modulation spectrum was extracted using the method developed by Singh and Singh (2008). This area for each speaker was correlated with the self-reported perceived closeness to the other member of the pair and with the individual Autistic Quotient (AQ).

Results:

Results indicated a significant positive correlation between interpersonal closeness and articulation area in all three countries (India: r=0.43, p<0.01; United Kingdom: r=0.35, p<0.01; Italy: r=034, p<0.05). A significant negative correlation between AQ and articulation area was observed only in the UK sample only(r=-0.23, p<0.05), but not seen in the other countries.

Conclusions:

The positive relationship between interpersonal closeness and vocal modulation was observed in all three countries, suggesting cultural generalisability of this result. In contrast, autistic traits were negatively associated with vocal modulation only in the UK sample. This observation could be driven by differences in baseline levels of vocal modulation in different cultures, which can lead to potential culture-specificity in the manifestation of autistic traits.