Definition
Synchrony is the implicit, spontaneous temporal coordination of physiological, neural, and behavioral rhythms between people engaged in face-to-face interaction — including postural mirroring, vocal-rhythm entrainment, gaze reciprocity, and coupled brain oscillations — which both signals and generates interpersonal rapport and social bonding.
Goleman draws on synchrony research to describe how other focus in action produces a feedback loop: attending carefully to another person induces synchrony, synchrony signals attunement, and perceived attunement deepens the quality of the connection.
Why it matters
How it works
The mechanisms of behavioral synchrony
Psychologist Ulric Neisser and, later, social psychologists including William Condon (in frame-by-frame film analysis in the 1960s) documented that people in conversation display interactional synchrony: microsecond-level coordination of listener body movements with speaker speech rhythm. The listener's head tilts, finger taps, and blink rate align with the prosodic contours of the speaker's voice, below the threshold of conscious awareness. This unconscious motor matching appears to be mediated by the mirror neuron system and related resonance circuitry.
Neural coupling
Uri Hasson's lab at Princeton showed via fMRI (2010) that the brain activity of a speaker and a listener closely coupled during naturalistic storytelling — the listener's neural response patterns mirrored the speaker's with a short lag (a few seconds). Crucially, the degree of coupling predicted comprehension accuracy: greater neural synchrony meant the listener understood more. Hasson coined the phrase "speaker-listener neural coupling" and showed that it could also operate as a leading signal — in some brain regions the listener's activity preceded the speaker's, reflecting anticipatory modeling of what the speaker would say next.
Physiological synchrony and bonding
Synchrony extends below behavior into physiology. Infant–caregiver heart-rate coupling during face-to-face play has been documented in multiple labs; greater physiological coupling predicts stronger attachment security at follow-up assessments. In adult romantic pairs and close friendships, respiratory and cardiovascular synchrony have been measured during synchronous activities (singing, rowing, guided breathing). Oxytocin release — associated with bonding, trust, and approach motivation — appears to both facilitate and result from physiological synchrony.
The leader effect
Goleman draws on Daniel Stern's concept of affective attunement and applies it to leadership: leaders who pay full attention to their interlocutors — without divided attention, device checking, or interpersonal distancing — produce stronger synchrony responses. This is partly why the physical practice of being fully present (devices away, body oriented toward the other person, following their vocal rhythm) has measurable effects on how a leader is perceived and trusted, independent of what is actually said.