It is often said that humans are visual animals, but there is little doubt that our exceptional capacity for social communication is auditory-vocal in nature. Importantly, this capacity is not limited to conversational speech, but is also utilized in more abstract aspects of sound ranging over proselytizing, poetry, repetitive chant, and music. A core feature of this speech-music continuum is the ability to convey affect through sound ? made possible by an auditory-vocal functionality that has evolved to reflexively attribute affect to voice-like stimuli. A system for processing auditory-vocal affect is critical to human social behavior: its refinement predicts social fluency, as individuals who are skilled at sharing in affect tend to be more socially integrated; and its impairment predicts social deficits, e.g., in autism spectrum disorder (ASD), schizophrenia, and major depressive disorder. Despite its central role in social behavior, we lack insight into the neurobiology that underlies the processing of auditory- vocal affect and why it fails to operate normally in prominent brain disorders. This gap in knowledge is directly related to the absence of a psychometrically robust, objective, and efficient assay, i.e., a ?gold standard? test of Auditory-Vocal Affect. Accordingly, Aim 1 of this proposal is to develop a gold standard Test of Auditory-Vocal Affect (the ?TAVA?) and collect large-scale normative data to support it. To do so I will: (a) use a combination of carefully designed speech and music stimuli to overcome obstacles faced by previous tests and tease apart issues of language processing from a core impairment in auditory-vocal affect processing; and (b) deploy the TAVA online.
Aim 2 tests whether the TAVA can accurately discriminate adults with ASD from neurotypical adults in a controlled laboratory study.
And Aim 3 tests whether a single-dose of intranasally administered oxytocin vs. placebo can ?move the needle? on TAVA performance in ASD, as implicated in previous studies of affect processing and ASD. My overarching hypothesis is that impairment in auditory-vocal affect functionality is a fundamental but poorly defined dimension of the core social deficits that define ASD. My rationale is that deficits in the perception of affect in speech are repeatedly described in ASD but, in contrast to visuo-facial affect, remain under-interrogated and poorly understood. If I am successful, I will have defined a new standard for assessing auditory-vocal affect functionality, suitable for behavioral phenotyping and as an objective assessment in ASD specifically and in clinical research more generally. Furthermore, my results will provide a foundation for future investigations into the neurobiological bases of auditory-vocal affect that promises to define their contribution to social function and dysfunction in mental health. Finally, the research goals outlined here synergize with a training plan that fills critical gaps in my basic science background. Specifically, I seek to acquire skills in neuroendocrinology, clinical research, and advanced statistical methods that will allow me to apply my interdisciplinary background in auditory-vocal communication ? focused on speech, music, and affect ? to relevant problems in mental health research as I transition to research independence.
Despite the critical importance of the auditory-vocal channel in human social communication, the contribution of its impairment to core social deficits associated with major brain disorders remains an under-represented topic in mental health research. This is particularly true in autism spectrum disorder, where a thin line of research points to difficulties in processing the affective information contained in speech. This proposal aims to develop the first psychometrically robust, objective, and efficient assay of auditory-vocal affect using an innovative combination of speech and music stimuli to triangulate the core impairments and lay the foundation for a rigorous behavioral definition and neurobiological analysis.
