Another essay deals with a group of aphasiacs - people who through damage to their speech centres can no longer understand speech - who watch a televised speech by an unnamed politician (heavily hinted to be Ronald Reagan), and who are brought to hysterical laughter by the insincerity of his tone and body language.
From the Telegraph. I have never got around to reading Oliver Sacks, but this sentence might tip me off the chaise lounge of procrastination.