What could have made consciousness an “unmentionable topic” by the 1980s?

Behaviorists argued that because consciousness could not be directly measured, it could not be studied scientifically and therefore should be dropped from scientific investigation. In the 1960s, psychologists’ interests were guided by the metaphor that human thinking processes are similar to a computer’s information processing. Though computers can be said to think, they cannot be said to have feelings, so this metaphor left little room for studies of consciousness.

What does it mean to say that consciousness is “subjective”?

This means that it only exists, and can only be assessed, from the viewpoint of the individual who is having the conscious experience.

What psychological quality must something have in order to say that it has “consciousness”?

Consciousness involves feelings. Only beings with subjective feelings can be said to have consciousness.

On what basis did the French philosopher Rene Descartes declare that consciousness is a basic fact of life?

In searching for facts he could identify as true, Descartes concluded that the only thing he could not doubt was that he existed and that he had conscious experience. The act of doubting his existence further proved he existed because someone had to be doing the doubting.

When, during development, do humans first experience consciousness?

Consciousness begins before birth: In one study conducted with both 27- and 35-week-old fetuses (Shahidullah & Hepper, 1994), researchers found that all the fetuses were aware of a sound presented outside their mother’s abdomen.

Do animals have consciousness? How do we know?

Yes. When animals perform tasks, they are distractible in much the same way that people are. Biological evidence indicates that the brain systems necessary for human consciousness exist in mammals other than humans.

Do animals have self-consciousness? How do we know?

Mirror self-recognition tests suggest that few animals show any sign of self-consciousness. Great apes and dolphins pass this test, but dogs and cats do not.

Why don’t robots have consciousness?

Robots are programmed to process information according to logical rules. Consciousness involves not only logical thought, but also emotions, sensations, and other feelings.

Is the mind separate from the body?

According to dualism, the mind and body are said to be two separate entities. The physical body projects images of the world into one location in the brain, where the nonphysical mind views it.

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What are some limitations of dualism?

One limitation is the mind–body problem. If the mind were a nonphysical entity, it would be impossible for it to influence the body. Another limitation is the homunculus problem. To say there is a structure in the brain that consciously experiences sights and sounds is to suggest that the brain contains a small conscious person-in-the-head, or homunculus, which raises the question: “How is it that the homunculus is conscious?”

How can one explain consciousness without proposing that the images of the outer world are reproduced within the brain?

In Daniel Dennett’s theory of consciousness, the brain does not reproduce stimuli. It merely detects features of stimuli and makes guesses about what type of object is out there. In this theory, different parts of the brain detect different features. There is no “theatre” in the mind in which the world is reproduced.

What is the evolutionary advantage of consciousness?

Consciousness enables organisms to take different types of information into account, and combine these facts when deciding how to act.

How evolutionarily old is consciousness?

Consciousness has been around for about 300 million years.

What subsystems of the brain are necessary for an organism to have conscious experience? How do we know?

Thalamo-cortical circuits integrate activity in multiple brain regions and thus serve as a basis for consciousness. Research by Alkire et al. (2008) indicates that anesthetics induce unconsciousness by reducing activity in the thalamus, implying that the thalamo-cortical circuits are key to consciousness.

What characterizes REM and non-REM sleep?

During REM sleep, heart rate, blood pressure, and breathing rate vary, just as they do during waking periods, and men and women experience genital arousal. During non-REM sleep, heart rate and blood pressure are lower than when you are awake and are very consistent, as is your breathing rate. Body temperature drops during non-REM sleep. Brain activity during REM sleep resembles brain activity during waking periods far more than brain activity during non-REM sleep. People dream during both REM and non-REM sleep, but during REM sleep, dreams are more frequent and more vivid.

Why, during REM sleep, do our eyes move rapidly but our muscles stay relatively still?

Our eyes may be “scanning” the dream imagery or they themselves may contribute to the production of the dream images. Our bodies remain still because the brain changes the release of neurotransmitters that, during waking periods, activate cells that control motor movement.

What characterizes sleep stages?

During the first 90 minutes of sleep, you experience a series of three non-REM sleep stages during which heart and breathing rates progressively decrease, and brain waves look less like those that occur when you are awake. After about 90 minutes, instead of remaining in deep sleep, you emerge from it and experience your first period of REM sleep, after which you head back down again, through the non-REM stages. As this cycle repeats itself during the night, the REM periods become longer and you do not descend all the way down to the deepest stage of non-REM sleep.

How have sleep labs been used to study the timing of the body’s internal clock?

Sleep labs can create an environment where external cues to length of day, such as patterns of light and dark, are altered from a 24-hour cycle. Research participants are monitored to see if shifts in the external environment change their biological rhythms. In one study, two groups spent a month living in a lab. One was placed on a 28-hour-day schedule, and the other on a 20-hour-day schedule. Results indicated that both groups had a 24-hour circadian rhythm.

Why do we sleep?

The low metabolic rate of non-REM sleep gives the body time to repair damage, though recent research indicates that sleep may only be necessary for repairing the brain, not the body as a whole. The mental activity of REM sleep may help the brain to establish neural connections required for processing stimuli when awake. Food needs may influence sleeping patterns.

In what ways does sleep deprivation impair performance?

Sleep deprivation can make individuals feel more anxious and depressed, and exhibit higher levels of paranoid thought. It can reduce the ability to concentrate, remember information, and solve problems, and it can also impair performance on activities that require sustained concentration and quick reactions, such as driving.

What characterizes sleep disorders?

Narcolepsy is a disorder in which people experience sudden, extreme feelings of sleepiness during the day that are sometimes accompanied by “microsleeps.” In sleep apnea, people suffer from brief pauses in breathing which awaken them. Insomnia is a prolonged difficulty in falling asleep or staying asleep when you have an opportunity to sleep.

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How bizarre is the content of our dreams?

Not very. People dream about conversations and work activities in school or a work environment; interactions with either romantic partners or family members, generally in indoor settings; sports activities; flying, fighting, or war (men’s dreams); or shopping or colors (women’s dreams); and motion, such as running or driving fast, combined with violence, threats, and fear.

Why do people dream?

According to Freud, dreams fulfill wishes, thereby releasing sexual and aggressive energies that would otherwise disrupt our sleep. According to the activation-synthesis theory, dreams are the brain’s way of making sense of random brain signals. An evolutionary perspective is that dreams are mental simulations that serve as a kind of rehearsal for real-life threats.

What is meditation designed to do and what are its two main techniques?

Meditative methods are designed to increase people’s ability to concentrate. In one technique, people concentrate their attention on a particular object or event while meditating. In a second method, people may try to clear their mind of all thoughts.

How do we know that meditation improves mental abilities?

In one study (Slagter et al., 2007), people who received meditation training showed greater increases in the ability to focus and sustain their attention on a task than did the control group.

Is everyone hypnotizable?

People differ considerably in their susceptibility to hypnosis.

How is a hypnotic state induced?

Participants are encouraged to focus their attention on an object while relaxing. The hypnotist provides suggestions to promote deep relaxation. If the person’s eyes close, the hypnotist instructs the participant to focus on the words of the hypnotist, and then leads the person into a hypnotic state from which, the hypnotist suggests, the participant will not emerge until told to do so.

How do we know hypnosis works?

In one study (Hilgard et al., 1975), a hypnotist made two suggestions to participants: (1) They would not consciously experience any pain when one of their hands was placed in ice cold water but (2) a “hidden part” of them would be aware of the pain. The participants were then asked to put a hand in extremely cold water. Indeed, individuals did not consciously experience the pain of the ice water, though the “hidden part” did.

What are the effects of hallucinogens, opioids, stimulants, and depressants and how do they work?

Hallucinogens cause people to hallucinate and to lose contact with reality. The drug affects the actions of the neurotransmitter serotonin.

Opiate drugs such as morphine contain opioids, chemical substances that reduce pain by lessening the transmission of pain signals from the body to the brain. Opiates reduce pain but can also produce powerful feelings of euphoria and ecstasy, making them highly addictive.

Stimulants such as caffeine are psychoactive drugs that increase nervous system activity and thus enhance alertness and energy. Stimulants also can enhance people’s sense of psychological well-being and self-esteem and can lower their inhibitions. Amphetamines are powerful stimulants that increase alertness and produce euphoric feelings by affecting multiple neurotransmitters, including dopamine.

Depressants are psychoactive drugs that reduce arousal in the central nervous system. In so doing, they can lower conscious experiences of excitability and anxiety. Depressants achieve these effects, in part, by increasing the effects of inhibitory neurotransmitters, that is, neurotransmitters that reduce activity in the brain. Benzodiazepines are depressants that activate the brain’s reward center and thus produce pleasurable feelings.