External stimuli may influence an individual's consciousness in many ways. The use of drugs, accidental or intentional damage to brain tissue, and hypnosis all fall within the category of external influences.
Psychoactive Drugs. Psychoactive drugs are drugs that affect the central nervous system, causing subjective changes in perception, emotion, and other conscious processes. These agents include depressant drugs, narcotic drugs, stimulants, hallucinogens, and many more. The primary reason for using psychoactive drugs appears to be social influence from peers. Other reasons for use may involve a physical problem such as insomnia, or a psychological need such as relief from anxiety. The study of the psychological effect of drugs is called psychopharmacology.
Psychologists make several distinctions regarding behaviors associated with drugs. First, they distinguish between drug use, where no impairment or actions harmful to others seem to occur, and drug abuse, where users' daily actions or health may be significantly impaired and harmful actions toward others may result.
EXAMPLE 6.11. A casual alcoholic drink with friends at an evening party constitutes drug use but is unlikely to result in drug abuse. Repeated binge drinking that impairs health, jeopardizes others (for example, driving while intoxicated), or impairs normal functioning on the job would be classified as drug abuse. Interestingly, some forms of abuse may not be readily recognized: Many people abuse the intake of caffeine, drinking coffee or soft drinks to the extent that failure to have the beverages causes various forms of impairment.
Psychologists also distinguish between physiological drug dependence and psychological drug dependence. Physiological drug dependence occurs when the use of a drug causes a change in the body's chemical balance and only continued use can maintain that changed status. Psychological drug dependence is the continued belief that the drug is needed even if the physical demand has been eliminated. The use of many drugs leads to both physical and psychological dependence.
EXAMPLE 6.12. Many people recognize the dependencies associated with drugs when they try to quit smoking. The physiological need for nicotine (one of the active components associated with smoking) persists for several weeks after one stops smoking. Even when the physiological need has dissipated completely and is no longer a concern, many people find that the psychological draw of smoking is difficult to overcome, thinking of smoking as a stress reliever or a social necessity.
As the body becomes accustomed to the use of a drug, it often develops a drug tolerance, meaning that the effect produced by the drug can be achieved only if a greater amount is used. Stopping the use of drugs often leads to withdrawal effects, which are unpleasant side effects produced by the body's compensatory or tolerance mechanisms.
Depressants. Also known as "downers," central nervous system (CNS) depressants slow the operation of the CNS. In therapeutic use, they often are prescribed to relieve anxiety or combat insomnia.
Alcohol. Alcohol, a depressant, is one of the most widely used psychoactive drugs. When taken in sufficient quantities (which vary from one individual to the next), alcohol can depress certain aspects of CNS functioning, causing conscious reactions that differ noticeably from those produced in a nonalcoholic state. The mental "high" produced by alcohol ingestion is accompanied by lowered inhibitions and impairment of motor coordination. Extreme excessive use can cause death.
EXAMPLE 6.13. The flirtatiousness of a person at a cocktail party may be the result of the depression of certain brain activity by alcohol. Continued drinking may lead to continued changes in brain activity, with the result that the "life of the party" may become hostile, lose motor coordination, and even pass out.
Barbiturates. Another category of depressant drugs is barbiturates. These drugs frequently are prescribed by physicians to induce sleep (counteracting insomnia, for example) or relieve stress. Nembutal and Seconal are common barbiturates.
Narcotic Drugs. Narcotic drugs are agents that relieve anxiety, produce relaxation, or reduce pain. Abuse of the two most common narcotic drugs, heroin and morphine, has become widespread. Initial misuse of narcotics commonly occurs for social reasons, but repeated dosages lead to a physiological dependence that continues to increase. This dependence has two aspects, the need for larger doses to prevent withdrawal symptoms (which can be quite severe) and the need for larger doses to produce the euphoric effect. Often, satisfaction of these needs leads to illegal activities to procure the narcotic.
Caffeine is present in many commonly used products, including coffee, tea, soft drinks, and chocolate. Many people develop a physiological dependence on caffeine, often without recognizing that this is the case.
EXAMPLE 6.14. Evidence for caffeine dependence is found in the "weekend headache." Many people become accustomed to early-morning ingestion of coffee, tea, or soft drinks but vary this routine on the weekend. Failure to have the early-morning beverage produces headaches and in some cases may produce depression as well.
Nicotine, which is present in tobacco products, activates neurons in much the same manner as does cocaine, although the effects of cocaine are thought to be more pronounced. Both, however, are highly addictive.
Cocaine creates feelings of euphoria, confidence, and physical and mental alertness. The fastest-acting version of cocaine is "crack," which is smoked and therefore enters the bloodstream, affecting the brain, within seconds. In extreme cases, prolonged use of cocaine or "crack" can lead to psychotic behavior, including hallucinations, delusions, and extreme emotional disturbance.
Amphetamines, such as Benzedrine or Dexedrine, are popularly known as "speed." The use of amphetamines in relatively small amounts usually produces increased alertness, a sense of energy, and positive emotional feelings. When used excessively or for a prolonged periods, amphetamines can produce feelings of persecution, negative emotions, and even convulsions or death.
Hallucinogenic Drugs. Many psychologists classify marijuana as a hallucinogenic drug. Smoking marijuana or eating it after it has been cooked may produce a psychoactive drug effect. Often the marijuana "high" is a state of elation in which the user claims an enrichment of sensory experiences.
Research into the effects of marijuana has shown that the effects produced may be a function not only of the amount and characteristics of the marijuana used but also of the expectations of the user. Motivation, past experience, and many other variables may create potential effects greater or lesser than those expected from the properties of the marijuana itself. Some studies have suggested a reverse tolerance effect in which less drug is needed to produce the same "high." This seems attributable to expectations and familiarity with the techniques for using the drug.
EXAMPLE 6.15. Expectations sometimes produce remarkable effects. People have been known to get "drunk" when drinking cola or "high" when smoking oregano. The social setting, a person's beliefs, and many additional factors contribute to such behavior.
Other hallucinogenic drugs, such as LSD, PCP, and mescaline, are available legally only in controlled circumstances such as medical research. These drugs typically produce strong hallucinations, with extreme distortion of "normal world" experiences. One characteristic of these drugs is that the effect produced by their use cannot be predicted reliably. It is even difficult to predict whether the mental experiences that result will be considered favorable or unfavorable. In addition, with LSD particularly, users report "flashbacks" long after the initial use of the drug.
Hypnosis. Dramatic demonstrations of external control of consciousness often are provided by hypnosis. Not all people are equally susceptible to hypnosis. Five to 10 percent of the population cannot be hypnotized at all, while a similar percentage can reach deep hypnotic trances. However, the effects of hypnosis tend to be similar for most people between these extremes.
A hypnotized individual accepts the hypnotist's directions, showing little or no emotional feeling (unless prompted to do so) and increased suggestibility. The hypnotist usually can restrict or direct the subject's attention. Furthermore, a hypnotized subject may experience a distorted perception of reality or show pronounced relaxation or alertness, depending on the hypnotist's instructions. People who achieve a very deep hypnotic state often report a feeling of a mystical experience, but some psychologists believe that reports of hypnotic states are "faked behaviors" that represent the subjects' desire to please or satisfy the hypnotist.
EXAM PLE 6.16. One use of hypnosis that has had much media attention is that of trying to increase or enhance memory by using the technique. Victims of crimes have been hypnotized in attempts to generate memories that will reveal something about the crime and lead to capturing the criminal. While some dramatic cases appear to support this use of hypnosis, such as remembering the license plate number of a vehicle used in a crime, the general finding is that success in using the technique in this manner is not well substantiated.
Brain Damage. Consciousness may be affected by certain types of brain damage, including both accidental damage and some intentional surgical techniques.
EXAMPLE 6.17. The case of Phineas Gage is renowned in psychology as one of the first documented examples of the effects of the destruction of brain tissue on conscious processes. Struck in a work accident by a piece of pipe that entered his eye socket and exited through the front top portion of the skull, Gage lived but lost brain tissue in the region of the frontal lobe. Very noticeable changes in his behavior were noted, especially in his emotional reactions to certain events. The loss of brain tissue apparently changed his way of responding, while all other variables remained basically the same.
The most obvious example of a surgical effect on consciousness is the split-brain procedure, which separates the functioning of the two cerebral hemispheres by dividing the corpus callosum (see Section 3.3). The separated hemispheres show individualized consciousnesses and in some cases respond differently to the same stimulus.
It is not possible to predict all the effects that may be produced by damage to the brain, whether accidental or intentional. Changes in emotional reactions, memory skills, or perceptual understandings have been demonstrated by testing patients before and after surgery. However, mapping of the brain is not complete enough for consistently accurate predictions to be made.
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