private void writeBehavior(Behavior b, XMLStreamWriter w) throws XMLStreamException {
		if ("beat".equals(b.type())) {
			writeEmpty(w, "gesture",
				a("start", asSync(b.low())),
				a("lexeme", "BEAT"));
		} else if ("brows".equals(b.type())) {
			writeEmpty(w, "faceLexeme",
				a("start", asSync(b.low())),
				a("end", asSync(b.high())),
				a("lexeme", "RAISE_BROWS"));
		} else if ("face".equals(b.type())) {
			writeFace(b, w);
		} else if ("gaze".equals(b.type()) && b.has(Features.DIRECTION, "AWAY")) {
			writeEmpty(w, "gaze",
				a("start", asSync(b.low())),
				a("end", asSync(b.low(), b.low()==0? 0.5 : 0.3)), // TODO configurable
				a("target", "away")); // TODO configurable
		} else if ("headnod".equals(b.type())) {
			writeEmpty(w, "head",
				a("start", asSync(b.low())),
				a("lexeme", "NOD"));
		} else if ("posture".equals(b.type())) {
			writeEmpty(w, "postureShift",
				a("start", asSync(b.low())));
		}
	}