Oxytocin, which is known to contribute to pair-bonding, encourages men to expand their personal "Don't come near me" bubble when around an attractive woman — but only when those men are in relationships, researchers found.

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Oxytocin, which is known to contribute to pair-bonding, encourages men to expand their personal "Don't come near me" bubble when around an attractive woman — but only when those men are in relationships, researchers found.

Thinkstock