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Abstract

Joint attention refers to the ability to coordinate one’s own attention with another on a third entity (e.g. object or common goal). This uniquely human ability emerges late in the first year of life and is critical to social-cognitive and language development; yet the neural bases for this pivotal skill remain largely understudied. Joint attention includes both Responding to Joint Attention (RJA), or following another’s bid for shared attention on an object, and Initiating Joint Attention (IJA), or initiating a bid for shared attention on an object. To identify the neural bases of both IJA and RJA we implemented a dual-video set-up in which both subject and experimenter could monitor each other via video feed in real-time during fMRI data collection. In each trial, participants either followed the experimenter’s gaze to a target (RJA) or cued the experimenter to look at the target (IJA). A control condition, non-joint attention (NJA), was included in which the subject shifted gaze to a target while the experimenter closed her eyes. Greater activation was seen in the dorsal medial prefrontal cortex (dMPFC) and bilateral posterior superior temporal sulcus (pSTS) during joint attention (IJA + RJA) as compared to NJA. RJA elicited greater activation in posterior superior temporal sulcus (pSTS) than NJA while IJA recruited greater activation in dMPFC than NJA. This novel experimental set-up allowed for the first time identification of the neural bases of both initiating and responding to joint attention.