Levels of Consciousness

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The Scope of Consciousness
is somewhat broader: Consciousness is generally defined as your awareness of the outside world and of your mental processes, thoughts, feelings, and perceptions (Metzinger,
2000; Zeman, 2001). Let’s see how this definition applies as we explore the scope of consciousness and various states of consciousness.
The Scope of Consciousness
䉴 Can unconscious thoughts affect your behavior?
FIGURE 4 .
The Necker Cube
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Each of the two squares in the
learn Necker cube can be perceived
by
as either the front or rear surface of the cube. Try to make the cube
switch back and forth between these two
orientations. Now try to hold only one orientation. You probably cannot maintain
the whole cube in consciousness for
longer than about three seconds before it
“flips” from one orientation to the other.
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doing
Mental activity changes constantly. The features of consciousness at any instant—what
reaches your awareness, the decisions you are making, and so on—make up what is
called your state of consciousness at that moment (Tassi & Muzet, 2001). Possible
states include coma, deep sleep, hypnosis, meditation, daydreaming, and alert wakefulness. Consciousness can also be altered by drugs and other influences.
States of Consciousness
States of consciousness can be viewed as different points along a scale or continuum
of consciousness. For example, suppose you were aboard an airliner flying from New York
to Los Angeles. The pilot calmly scans instrument displays while talking to an air-traffic
controller. In the seat next to you, a lawyer finishes her second cocktail while planning
a courtroom strategy. Across the aisle, a young father gazes out the window, daydreaming, while his small daughter sleeps in his lap, dreaming dreams of her own. All
these people are experiencing different states of consciousness. Some states are active,
and some are passive. The daydreaming father lets his mind wander, passively noticing
images, memories, and other mental events that come to mind. Like the pilot, the lawyer
actively directs her mental processes. In her case, though, as she evaluates various
options and considers their likely outcomes, she is altering her state of consciousness
by sipping alcohol.
Generally, people spend most of their time in a waking state of consciousness. Mental processing in this state varies with changes in attention or arousal (Taylor, 2002). While
reading, for example, you may temporarily ignore sounds around you. Similarly, if you
are upset or bored or talking on a cell phone, you may tune out important cues from the
environment, making it dangerous to perform complex activities such as driving a car.
Levels of Consciousness
consciousness The awareness of external stimuli and our own mental activity
state of consciousness The characteristics of consciousness at any particular
moment.
conscious level The level of consciousness at which mental activities accessible to awareness occur.
nonconscious level The level of consciousness at which reside processes
that are totally inaccessible to conscious
awareness.
The events and mental processes that you are aware of at any given moment are said
to exist at the conscious level. For example, look at the Necker cube in Figure 4.1. If
you are like most people, you can hold the cube in one orientation for only a few
seconds before the other version “pops out” at you. The version that you experience at
any moment is at your conscious level of awareness for that moment.
Some events, however, cannot be experienced consciously. For example, you are not
directly aware of your brain regulating your blood pressure. Such mental processing
occurs at the nonconscious level, totally removed from conscious awareness. Some
people can learn to alter a nonconscious process through biofeedback training. In this
training, you receive information about your biological processes and try to change
them. Usually, special equipment is required, but you can approximate a
learn biofeedback session by having a friend take your pulse at one-minute interby
doing vals while you sit quietly. First, establish a baseline pulse; then imagine a
peaceful scene, or think about lowering your pulse rate. Then ask your friend
to softly say whether your pulse is higher or lower compared with the baseline. After
four or five minutes of having this information “fed back” to you, you will probably be
able to keep your pulse below the original baseline. Yet the pulse-regulating processes
themselves remain out of consciousness.
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