From "How dead is dead?" story in the Economist:
When, if ever, to withdraw medical support from such people, and thus let them die, is always a traumatic decision. It depends in part, though, on how the fully alive view the mental capacities of the vegetative—an area that has not been investigated much.
To fill that gap Kurt Gray of the University of Maryland, and Annie Knickman and Dan Wegner of Harvard University, conducted an experiment designed to ascertain just how people perceive those in a persistent vegetative state. What they found astonished them.
Find out what here .