Consciousness

• seCtIon FIVe: BoRDeRLAnDs

PRoFILe 15.2

Antti Revonsuo (b. 1963)

As an undergraduate in psychology

and philosophy, Antti Revonsuo

wrote his thesis on how science-fic-

tion stories present such traditional

philosophical problems as soulless

zombies and machine conscious-

ness. From research on the cognitive deficits of neuro-

psychological patients, he moved into philosophy for a

PhD on consciousness, combining philosophy, neural

PRoFILe 15.1

Allan Hobson (b. 1933)

Known for his AIM model of

dreaming states and his exten-

sive work on sleep, Allan Hob-

son is both an experimental

researcher and a psychiatrist,

and is Professor Emeritus at

Harvard Medical School. He began having lucid dreams

after reading about them in 1962, and for decades he

kept a dream journal. His dreams stopped after a stroke

in 2001 but began again thirty-six days later, just as he

began to walk again. He has long tried to understand

the function of sleep, recently proposing that the brain

optimises itself during sleep by minimising free energy

and reducing the complexity of its model of the world.

Hobson is a fervent critic of psychiatry’s long reliance on

psychoanalysis; he describes Freud’s ideas as facile and

erroneous, saying we have to wait for psychoanalysts to

die since they will never recant. He has a dairy farm in

Vermont where he has restored old buildings to house

exhibitions and an art gallery. He is the author of many

books on dreaming, including The Dream Drugstore

(2001) and Psychodynamic Neurology: Dreams, Con-

sciousness, and Virtual Reality (2015).

dreams is that while we are dreaming we rarely recognise how

strange they are.

Finnish dream researcher Antti Revonsuo and his colleagues

studied bizarre dreams in more detail using 592 dreams from

the dream diaries of fifty-two students and measuring the

bizarreness of their dream characters (Revonsuo and Tarkko,

2002). The most common type was bizarreness of dreamers’

semantic knowledge about dream characters. Features intrin-

sic to the representation of a character were less often bizarre

than the relationship between the character and the setting

or the location, such as dreaming of ‘the President having a

cup of coffee in my kitchen’; there were also frequent changes,

appearances, and disappearances of people and objects.

How can we make sense of all of this? Do these features of

dreaming follow any patterns or rules? And if they do, can we

understand them in terms of the underlying physiology?

FROM PHYSIOLOGY

TO EXPERIENCE

Dream research seems to provide a perfect context in which to

look for the neural correlates of consciousness. Various phys-

iological, neurochemical, and behavioural variables can be

correlated with subjective descriptions of dreams. On the sur-

face, this might suggest the possibility of either reducing the

experiences entirely to physical states, or equating the expe-

riential with the physical, leading to the idea of just one com-

bined objective/subjective space mapping and one concept

of dreaming sleep, rather than two. This correlation between

physiological states and subjective reports has supported

decades of productive research into sleep and dreaming,

and made it possible to map the three major states (waking,

REM sleep, and non-REM sleep) in terms of their physiology.

But does this help us to understand subjectivity or avoid the

hard problem?

The best-known attempt at this sort of mapping is probably

Hobson’s AIM model (Chapter 13) depicting the idea of a uni-

fied ‘brain–mind space’. The three states can be positioned in

brain–mind space by measuring them along the three dimen-

sions. Adding time as a fourth dimension, the values of A (acti-

vation energy), I (input source), and M (mode, or amine-choline

ratio) all change and the process of cycling through the nor-

mal sleep stages can be represented by movement from one

region of the space to another (Hobson, 2007). As in Tart’s

original conception for mapping altered states of conscious-

ness (ASCs), large areas of the space remain unoccupied and

the different states are discrete ‘states of consciousness’. They