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Psychology · Foundations

Consciousness

9 min read 5 practice questions
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On this page 9 sections
  1. In 30 seconds
  2. Why this matters
  3. The college version
  4. Eli explains
  5. Worked example
  6. Key takeaway
  7. Quick check
  8. Study tools
  9. Sources & references

In 30 seconds

is a person's of themselves and their environment — the APA's working definition. That awareness is not an on-off switch: it runs on a spectrum from alert through and to altered states like daydreaming. is the spotlight of consciousness, and it has real limits: nobody truly multitasks. Some mental activity runs outside awareness altogether. And science still cannot explain why subjective experience exists at all — consciousness remains one of the hardest problems in science.

Why this matters

Consciousness is the one thing every person experiences every waking minute, so it feels too familiar to need study — until you notice how much it varies. Knowing that awareness is a spectrum helps you read your own states: why a drowsy driver is dangerous, why a daydreaming commuter misses an exit, why saying "I'll just multitask" usually means doing two things badly. The vocabulary matters too: psychologists use consciousness, attention, and the unconscious as precise terms, not loose metaphors. And the honest science lesson is humbling — the field measures brain activity and behavior, yet explaining why there is any inner experience at all remains unsolved. That gap is worth knowing, because every claim that "science has explained consciousness" oversells the evidence.

The college version

What consciousness is

Consciousness is a person's awareness of themselves and their environment. That is the working definition the American Psychological Association uses: the APA Dictionary describes consciousness as an organism's awareness of something either internal or external to itself — your own thoughts, feelings, and bodily sensations on the inside, and the room, the people, and the sounds around you on the outside. OpenStax's Psychology 2e states the same idea: consciousness describes our awareness of internal and external stimuli. Awareness of internal stimuli includes feeling pain, hunger, thirst, and sleepiness, and being aware of our thoughts and emotions; awareness of external stimuli includes seeing sunlight, feeling the warmth of a room, and hearing a friend's voice. Two features of this definition matter. First, consciousness is not a thing you possess but an activity — awareness — that you can be more or less in. Second, the definition points inward and outward at once, which is why a person can be fully conscious of a headache while barely registering the conversation happening beside them.

Levels of awareness — a spectrum

Awareness comes in degrees, not just on or off. OpenStax is explicit: we experience different states of consciousness and different levels of awareness on a regular basis, and consciousness can be described as a continuum that ranges from full awareness to deep sleep. Four named levels anchor the spectrum. Alert wakefulness is the high end — the APA Dictionary calls it a condition of awareness of one's surroundings, and OpenStax describes it as high sensory awareness, thought, and behavior. Drowsiness sits below it: the APA defines it as low alertness in which sustained mental effort is hard. Sleep is further down — the APA calls sleep a circadian state with partial or total suspension of consciousness, and OpenStax notes it is marked by reduced sensory awareness. Altered states are the fourth anchor: the APA Dictionary defines an as psychological functioning significantly different from ordinary consciousness, and OpenStax lists daydreaming, intoxication, and unconsciousness due to anesthesia as examples. The honest note: any list of levels is a map, not the territory. Between fully alert and deeply asleep, people drift through countless intermediate states — the half-awake bus stop, the lecture you sat through without hearing it.

Attention — the spotlight of consciousness

Attention is the focusing of awareness. The APA Dictionary defines attention as a state in which cognitive resources are focused on certain aspects of the environment rather than on others, and it flags the assumption behind decades of research: human beings do not have an infinite capacity to attend to everything. Attention is what the mind does with its beam. Original example: Nina sits at a crowded café table, absorbed in her friend's story. She hears it clearly; she does not notice the barista calling her name or the door swinging behind her. Her awareness has not shrunk — her attention has aimed it. Because the beam is limited, aiming it at one thing darkens the rest. The Noba Project's attention module treats selective and divided attention as distinct problems and studies multitasking as divided attention, with real implications — including the costs in situations such as distracted driving. The honest note about multitasking: nobody truly does two attention-demanding things at once. People switch the spotlight back and forth, and every switch costs time and accuracy. Texting while driving is not two tasks done together; it is the spotlight flickering between the road and the phone.

Sleep and the unconscious

Sleep is a changed state of consciousness. That sentence carries real consequences: in sleep, the APA notes, consciousness is partially or totally suspended — which is why a sleeping person does not answer questions or notice a door slamming, yet still wakes to an alarm that matters. Sleep gets its own lesson in this course; here it matters as the clearest proof that consciousness is not a fixed state. The unconscious is a different idea. In its plain descriptive sense, the unconscious is mental activity that goes on outside awareness — processes your mind runs without you watching them. OpenStax gives the everyday example: driving home from work while daydreaming, you are capable of all the complex tasks involved in operating the car even though you are not aware of doing so. The word carries a heavier history — the APA Dictionary notes that in psychoanalytic theory the unconscious is a region of the psyche holding memories, conflicts, wishes, and repressed impulses. This lesson uses the plain sense only: mental activity outside awareness. No theory of repression required.

The honest note — the hardest problem in science

Everything above describes consciousness; none of it explains why it exists. Philosopher David Chalmers, in a 1995 paper that gave the question its name, drew the line clearly: explaining how the brain performs functions — recognizing faces, storing memories, steering attention — is hard but tractable; explaining why any of it is accompanied by inner experience at all is something else entirely. He called that the hard problem of consciousness. The honest note is factual: consciousness remains one of the most difficult open questions in science. Researchers can measure brain activity, test attention, and study sleep; nobody can yet say how subjective experience arises from physical processes. The honest framing that follows: consciousness is, in the end, the experience of having a mind. That is why it is studied — and why it is still mysterious. The deeper philosophical debate about mind and body belongs to the philosophy curriculum, not to this lesson.

Eli, the EliExplains learning guide

Eli explains

The same idea, in plain words

Explain it like I’m 10

Consciousness is your mind being switched on: aware of your own thoughts and feelings and of the world around you. It is not an on-off light; it is more like a dimmer — fully bright when you are alert, lower when you are drowsy, nearly out when you sleep, and shifted to odd settings in daydreams and other altered states. Attention is the part of the beam you can aim. It has a narrow reach, which is why "multitasking" is mostly switching fast between tasks and losing a little with every switch. And some mental work runs in the dark, outside awareness entirely — like the driving you do on autopilot. The strange part: science still cannot explain why the lights are on at all.

Picture it like this

Imagine your mind as a dark theater and consciousness as the house lights. Most of the theater stays dim; the spotlight of attention picks out one performer at a time. When you are alert, the house lights are bright; when you are drowsy, they fade; during sleep they nearly go out. The spotlight can swing quickly, but it still lights only one spot at a time — nobody can watch two performers fully at once.

Where the picture stops working

A theater's lights are controlled by an electrician standing outside the building, while your consciousness is produced by your own brain — and nobody has found the switch. The spotlight also makes attention look like a single beam, but attention can be divided and spread in ways a single spotlight cannot. And a dark theater suggests nothing happens in the dark, yet a great deal of mental activity runs outside awareness, all the time.

Worked example

Ravi's evening shows the spectrum in one sitting. At 7:00 he is writing an essay, fully alert: he notices his own arguments and the room around him — the high end of the continuum. At 9:00, on the couch, he feels drowsy: his eyes drift and his mind keeps sliding off the book he is holding, the low-alertness state the APA Dictionary describes. By 9:30 he is asleep, consciousness suspended, his roommate's music unheard. At 11:00 the alarm on his phone pulls him partway up: awake enough to silence it, not awake enough to remember doing so. The next morning he drives his usual route to work while planning his day, and arrives with almost no memory of the drive — mental activity that ran outside awareness. One evening, four levels of awareness, and none of them "off."

Key takeaway

Consciousness is the experience of having a mind — an awareness of yourself and your environment that runs on a spectrum, aims through the limited spotlight of attention, and still cannot be fully explained by science.

Quick check

3 questions here, of 5 in this lesson’s practice set. Answers stay hidden until you check.

Question 1 of 3foundational

According to the working definition used in this lesson, consciousness is a person's awareness of —

Choose an answer, then check it.
Question 2 of 3intermediate

Kofi drives his usual route home while daydreaming about the weekend and arrives without remembering the drive itself. Which part of this scenario best illustrates mental activity outside awareness?

Choose an answer, then check it.
Question 3 of 3foundational

In the APA definition used in this lesson, attention is —

Choose an answer, then check it.
Practice all 5

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Practice this lesson
Study tools & related lessonsYou’ll learn to · Common mistakes · Easily confused · Key vocabulary · Related

You’ll learn to

  • Define consciousness as a person's awareness of themselves and their environment, using the APA working definition.
  • Describe four levels of awareness — alert, drowsy, asleep, and altered — and explain why awareness is a spectrum rather than an on-off switch.
  • Explain attention as the limited-capacity spotlight of consciousness, using an original example.
  • Analyze why genuine multitasking is largely a myth, based on how attention works.
  • Distinguish conscious mental activity from unconscious mental activity, and explain why the source of subjective experience remains an open problem.

Common mistakes

  • "Consciousness is the same thing as attention."

    Consciousness is your overall awareness of yourself and your environment; attention is the focused beam within it. You can be conscious of a room without attending to anything specific in it, and you can attend so hard to one thing that you stop noticing the rest.

  • "Awareness is either on or off."

    Awareness is a spectrum. Alert, drowsy, asleep, and altered are named points along a continuum that runs from full awareness to deep sleep, and people drift through intermediate states all day.

  • "Multitasking means doing two things at full quality at once."

    Attention has a limited capacity, so two attention-demanding tasks cannot both receive full focus at once. What is usually called multitasking is rapid switching between tasks, and every switch costs time and accuracy.

  • "The unconscious is a Freudian invention about hidden wishes."

    The plain descriptive sense is simply mental activity outside awareness — routines like driving a familiar route. The psychoanalytic theory of repressed wishes is one particular theory attached to the word, not its everyday meaning.

Easily confused

Consciousness vs. Attention

Consciousness is the overall awareness of yourself and your environment; attention is the limited-capacity focus within it. Awareness can be broad and unfocused; attention is awareness aimed.

Conscious mental activity vs. Unconscious mental activity

Conscious activity is something you are aware of doing — choosing the next word of a sentence. Unconscious activity runs without awareness — the routines of a familiar drive. Both are real mental activity; only one comes with a feeling of doing it.

Waking state vs. Altered state

Waking consciousness is ordinary awareness of your surroundings; an altered state is psychological functioning significantly different from ordinary consciousness — daydreaming, for example. Sleep is a changed state too, but it is the sleep topic's territory.

Key vocabulary

consciousness
A person's awareness of themselves and their environment — the APA working definition used throughout this lesson.
awareness
Perception or knowledge of something, internal or external; the activity at the center of consciousness.
wakefulness
A condition of awareness of one's surroundings, marking the high end of the consciousness spectrum.
drowsiness
A state of low alertness in which sustained mental effort becomes difficult.
altered state of consciousness
Psychological functioning significantly different from ordinary consciousness, as in daydreaming or intoxication.
attention
The focusing of cognitive resources on certain aspects of the environment rather than on others.
selective attention
Focusing awareness on one set of stimuli while other stimuli go unregistered.
unconscious (descriptive sense)
Mental activity that goes on outside awareness, such as the routines of a familiar drive.
sleep
A circadian state of partially or totally suspended consciousness and reduced sensory awareness.

Sources & references

  1. OpenStax Psychology 2e, Section 4.1: What Is Consciousness? — OpenStax, Rice University
  2. APA Dictionary of Psychology — consciousness — American Psychological Association (APA Dictionary of Psychology)
  3. APA Dictionary of Psychology — attention — American Psychological Association (APA Dictionary of Psychology)
  4. APA Dictionary of Psychology — unconscious (Ucs) — American Psychological Association (APA Dictionary of Psychology)
  5. APA Dictionary of Psychology — awareness — American Psychological Association (APA Dictionary of Psychology)
  6. APA Dictionary of Psychology — wakefulness — American Psychological Association (APA Dictionary of Psychology)
  7. APA Dictionary of Psychology — drowsiness — American Psychological Association (APA Dictionary of Psychology)
  8. APA Dictionary of Psychology — altered state of consciousness (ASC) — American Psychological Association (APA Dictionary of Psychology)
  9. APA Dictionary of Psychology — sleep — American Psychological Association (APA Dictionary of Psychology)
  10. Noba Project — Attention (chapter module) — Noba Project (Diener Education Fund)
  11. Chalmers, D. J. (1995). Facing Up to the Problem of Consciousness. Journal of Consciousness Studies, 2(3), 200-219. — David Chalmers (author's page) / Journal of Consciousness Studies

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Researched 2026-08-22

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