The pavlovian act of reaching, or needing to reach, for one's cell phone in a group social setting in response to someone else's cell phone activity (usually a ring, or vibration, or merely lighting up).
Cellivation is an emergent behavior in cell-phone dominated cultures and can cause significant disruptions in group social activity (see example below).
A group of people are at brunch engaged in a deep conversation about social psychology. Suddenly, a cell phone on the table vibrates. Before the person can reach their cell phone, the conversation abruptly stops as people reach for their cell phones. This is cellivation at its cultural worst. "KQ's cell phone rang causing Scott to cellivate and interrupt the conversation, subsequently helping to invent this word"