When a person is brain dead, or no longer has brain activity, they are clinically dead. Physiological death may take 72 or fewer hours. This is different than a vegetative state, which occurs when the cerebral cortex no longer registers electrical activity but the brain stems continues to be active. Individuals who are kept alive through life support may be classified this way.

Newborns do not scan objects this way; rather, they tend to look at the chin or another less detailed part of the face. However, by 2 or 3 months, they will seek more detail when visually exploring an object and begin showing preferences for unusual images over familiar ones, for patterns over solids, faces over patterns, and three-dimensional objects over flat images.