Hallucinations by Oliver Sacks - review

by Michael Corballis / 03 January, 2013
Oliver Sacks provides vibrant descriptions of the wide range of forms hallucinations can take – and seems to have experienced most of them himself.
Hallucinations by Oliver Sacks A curious feature of hallucinations is you can’t conjure them up at will. Yet they demonstrate the mind is stocked with images, and can produce involuntary but realistic perceptions that are immediate and vivid, to the point the perceiver mistakes the apparition for a real physical entity or the voice in the head as emanating from a real speaker. Nevertheless, they are often bizarre, and don’t correspond to actual events from the past. In contrast, you can consciously retrieve memories and even construct imaginary scenes, but these are diffuse and vague, and are not perceived as though happening in the present.

Hallucinations, then, just happen, but they are provoked by a wide range of circumstances. Sometimes it’s a matter of sensory loss: the deaf may hear voices, the blind may see vivid visual displays and people who have lost the sense of smell may experience bizarre odours.

Depriving people of sensory stimulation, as in an isolation cell, can induce hallucinations, as can conditions such as migraine, epilepsy, Parkinsonism, delirium, narcolepsy and psychosis. Oliver Sacks covers these and more, using his copious case notes, along with historical accounts, to provide vibrant descriptions of the wide range of forms hallucinations can take. Amazingly, he also seems to have experienced most of them himself.

He participated enthusiastically in the drug culture of the 1960s, and seems to have tried almost everything on offer, including cannabis, LSD, mescaline, morphine and even a mixed cocktail of amphetamine, LSD and a pinch of cannabis. This concoction produced a rare case in which he was able to consciously conjure a visual hallucination by demanding that indigo, the most elusive of the spectrum of colours, appear on a blank wall. It did, and he remained obsessed by indigo for some time afterwards.

Some hallucinations, such as heightened colours, distortions of size or movement, and the appearance of zigzag lines, can be plausibly explained in terms of what we know of visual neurophysiology. Less explicable are those giving the appearance of a real event, as when Sacks, high on a drug called Artane, greeted friends who had arrived at his door and proceeded to cook ham and eggs for them, only to discover they were not there at all.

Other hallucinations are simply bizarre – distorted faces, battle scenes, grotesque animals, visions of heaven and hell. Again, though, these are not like memories and don’t replay past events. They seem to be made up of stored fragments that normally go into our perceptions of the world, but are somehow disengaged, distorted and randomly combined.

It is a matter of wonder that there are so many otherwise unpalatable plants that induce hallucinations and altered states of consciousness. Sacks suggests they evolved psychoactive properties either to deter animal predators or to attract animals to eat the fruit and disseminate the seeds through defecation. But the symbiotic relation with humans seems especially pronounced, to the point we encourage the survival of plants with psychoactive properties by cultivating them, not always legally. All cultures have found chemical ways of inducing hallucinatory or stimulant effects, whether as part of religious ecstasy, simply for enjoyment or to enhance creativity – although the sense of creativity may itself be hallucinatory.

Sacks’s book is a fascinating compendium of hallucinatory effects and what causes them, written with his usual flair for exploring the minds of others, as well as of himself. Hallucinations unlock weird, wonderful but sometimes alarming aspects of the mind, and my only complaint is the book doesn’t really dig far enough into what it might all mean.

HALLUCINATIONS, by Oliver Sacks (Picador, $40).

Michael Corballis is emeritus professor of psychology at the University of Auckland and author of Pieces of Mind: 21 Short Walks Around the Human Brain.
MostReadArticlesCollectionWidget - Most Read - Used in articles
AdvertModule - Advert - M-Rec / Halfpage


Immigration, tourism hold at record levels
71637 2017-04-26 12:18:08Z Economy

Immigration, tourism hold at record levels

by RNZ

Immigration has reached another new record driven by people on work and student visas and returning New Zealanders.

Read more
'No magic figure' for immigration numbers - Andrew Little
71625 2017-04-26 10:11:38Z Politics

'No magic figure' for immigration numbers - Andrew…

by RNZ

Andrew Little has confirmed a Labour government would cut immigration by tens of thousands a year, but is refusing to give a definite figure.

Read more
Indefensible position: The case for Donald
71464 2017-04-26 00:00:00Z Politics

Indefensible position: The case for Donald

by Judith Baragwanath

Judith Baragawanath has had it up to her back teeth with Trump haters.

Read more
Australia's citizenship plan 'slap in the face' for NZers
71621 2017-04-26 00:00:00Z Politics

Australia's citizenship plan 'slap in the face' fo…

by Catherine Hutton

The government should get Australia to sort out the "mess" over new citizenship rules that appear to go back on last year's agreement for Kiwis.

Read more
The Guns of Navarone writer knew he had to have a Kiwi hero
71551 2017-04-26 00:00:00Z History

The Guns of Navarone writer knew he had to have a …

by Charles Hamlin

When Alistair Stuart MacLean sent his heroes up a sheer cliff, he knew he had to have a New Zealander in charge.

Read more
NZ spied on Japan to help US - NSA document
71615 2017-04-26 00:00:00Z World

NZ spied on Japan to help US - NSA document

by Craig McCulloch

Leaked US documents reveal Kiwi spies gathered information about Japan at a whaling conference, then passed it onto the NSA ahead of a crucial vote.

Read more
Mustard with your mustelid? The future of ethical protein eating
70342 2017-04-26 00:00:00Z Innovation

Mustard with your mustelid? The future of ethical …

by Margo White

If we want to feed the masses without wrecking the planet with more intensive agriculture, we might need to reframe our attitude to insects.

Read more