AMost viewers conclude that the changes occurring in Adam don't start until Adam turns eight because that's the age, to the day, that Adam1 died. With no more memories from Adam1 now, the space is clear for Zachary's memories to take over. This concept is termed cellular memory and is based on the belief that living tissues have the capacity to store memories and emotions and that these can be passed during transplants from donor to recipient. Thus, Adam2 received memories and emotions from both Adam1 and Zachary in his cloning. Cellular memory is considered a pseudoscientific theory by the medical community as there is no evidence to support it. Still, it forms the premise of many horror movies in which someone receives the heart, brain, hands, etc. of a donor and suddenly starts seeing life through the eyes of their donor, e.g., The Hands of Orlac (1960).