By: His Holiness The Dalai Lama
At the time of death attitudes of long familiarity usually take precedence and direct the rebirth. For this same reason, strong attachment is generated for the self, since one fears one’s self is becoming nonexistent. This attachment serves as the connecting link to the intermediate state between lives; the liking for a body in turn acts as a cause establishing the body of the intermediate (bardo) being.
From: Lati Rinbochay and Jeffrey Hopkins, Death, the Intermediate State and Rebirth in Tibetan Buddhism.