The Language Network Reliably "Tracks" Naturalistic Meaningful Nonverbal Stimuli

Auditory areas are recruited for naturalistic visual meaning in early deaf people

Congenital deafness enhances responses of auditory cortices to non-auditory tasks, yet the nature of the reorganization is not well understood. Here, naturalistic stimuli are used to induce neural synchrony across early deaf and hearing individuals. Participants watch a silent animated film in an intact version and three versions with gradually distorted meaning. Differences between groups are observed in higher-order auditory cortices in all stimuli, with no statistically significant effects in the primary auditory cortex. Comparison between levels of scrambling revealed a heterogeneity of function in secondary auditory areas. Both hemispheres show greater synchrony in the deaf than in the hearing participants for the intact movie and high-level variants. However, only the right hemisphere shows an increased inter-subject synchrony in the deaf people for the low-level movie variants. An event segmentation validates these results: the dynamics of the right secondary auditory cortex in the deaf people consist of shorter-length events with more transitions than the left. Our results reveal how deaf individuals use their auditory cortex to process visual meaning.

Language is primarily a tool for communication rather than thought

Language is a defining characteristic of our species, but the function, or functions, that it serves has been debated for centuries. Here we bring recent evidence from neuroscience and allied disciplines to argue that in modern humans, language is a tool for communication, contrary to a prominent view that we use language for thinking. We begin by introducing the brain network that supports linguistic ability in humans. We then review evidence for a double dissociation between language and thought, and discuss several properties of language that suggest that it is optimized for communication. We conclude that although the emergence of language has unquestionably transformed human culture, language does not appear to be a prerequisite for complex thought, including symbolic thought. Instead, language is a powerful tool for the transmission of cultural knowledge; it plausibly co-evolved with our thinking and reasoning capacities, and only reflects, rather than gives rise to, the signature sophistication of human cognition.