Connecting deeply with another mind is as enigmatic as it is fulfilling. Why people “click” with some people but not others is one of the great unsolved mysteries of science. However, researchers from psychology and neuroscience are converging on a likely physiological basis for connection – neural synchrony (entrainment). Here, we review research on the necessary precursors for interpersonal synchrony: the ability to detect a mind and resonate with its outputs. Further, We describe potential mechanisms for the development of synchrony between two minds. We then consider recent neuroimaging and behavioral evidence for the adaptive benefits of synchrony, including neural efficiency and the release of a reward signal that promotes future social interaction. In nature, neural synchrony yields behavioral synchrony. Humans use behavioral synchrony to promote neural synchrony, and thus, social bonding. This reverse‐engineering of social connection is an important innovation likely underlying this distinctively human capacity to create large‐scale social coordination and cohesion.

psychoacoustic theories of dissonance often follow Helmholtz and attribute it to partials (fundamental frequencies or overtones) near enough in frequency to affect the same region of the basilar membrane and therefore to cause roughness, i.e., rapid beating. In contrast, tonal theories attribute dissonance to violations of harmonic principles embodied in Western music. We propose a dual-process theory that embeds roughness within tonal principles. The theory predicts the robust increasing trend in the dissonance of triads: major < minor < diminished < augmented. Previous experiments used too few chords for a comprehensive test of the theory, and so Experiment 1 examined the rated dissonance of all 55 possible three-note chords, and Experiment 2 examined a representative sample of 48 of the possible four-note chords. The participants' ratings concurred reliably and corroborated the dual-process theory. Experiment 3 showed that, as the theory predicts, consonant chords are rated as less dissonant when they occur in a tonal sequence (the cycle of fifths) than in a random sequence, whereas this manipulation has no reliable effect on dissonant chords outside common musical practice.

Human social behavior relies on the coupling of minds. Here we show that patterns of pupil dilations reveal mental coupling between speakers and listeners. Speakers were videotaped and eye-tracked as they discussed positive and negative autobiographical memories. An independent group of listeners were then eye-tracked while they watched these videos. As pupillary dilations reflect the dynamics of conscious attention, we computed the morphological similarity of speaker-listener pupillary time-series data as a metric of shared attention. The emotional salience of each narrative was also assessed, dynamically, by independent raters. Collective pupillary synchrony between speakers and listeners was greatest during the emotional peaks of a narrative, and decreased as narratives became less engaging. Individual differences in speaker expressivity and listener empathy revealed greatest synchrony in high expressive-high empathic dyads. Together, these findings suggest that pupillary synchrony is an implicit corollary of shared attention that can be used to track mental coupling in real time. (PsycINFO Database Record