Text 19

HABITUATION

Text 18

Habituation is the simplest form of learning; it refers to an organism becoming familiar with a particular stimulus. Habituation occurs when there is a decrease in the strength of a response after a stimulus has been presented consistently, either in one prolonged stretch or briefly and repeatedly. Before habituation, each time an organism encounters a new or unexpected object, there is a “surprise reaction,” known as the orienting reflex. In humans the eyebrows lift slightly, the eyes widen, the heart beats faster, the muscles become slightly tense, the skin resistance drops, and a recording of brain waves would show a typical arousal pattern. After habituation, the same object causes no such reflex.

Habituation appears in even the simplest organisms. For example, when a sea snail’s gill is touched, the gill withdraws reflexively; if the touch is repeated tenth times the snail habituates and stops withdrawing the gill.

Like sensory adaptation habituation is an adaptive physiological process that allows an organism’s attention to shift to more important or threatening information. Whereas sensory adaptation might be defined as neuron fatigue, habituation can be compared to becoming a little bored.

Habituation has often been successfully to do research on learning in very young infants, because no “instruction” is required. Babies will look at any new visual stimulus; as the stimulus is repeated, however, the eventually habituate and spend less time gazing at it. Any significant change in the stimulus caused babies to orient toward it once more. Used to this way, habituation studies allow researchers to infer which changes babies notice and consider significant.

PUNISHMENT: USE WITH CARE

Punishment, as we have seen, involves any unpleasant event (such as shock or denial of privileges) that follows a response and weakens it. If a rat receives a painful electric shock each time it presses a lever, it will soon stop pressing the lever. Life is full of aversive or painful consequences that serve as punishments: parents spank children, students get failing grades, lawbreakers are fined or jailed. Thus, both as individuals and as a society, we regard punishment as a useful means of controlling behavior. Our environment provides many “natural” punishments that effectively suppress specific behavior. A child has to touch a hot stove only once. After slipping and falling on an icy sidewalk, anyone walks more carefully.

Sometimes punishment involves denying or removing some pleasant or desired object or event. A small girl who misbehaves is not allowed to watch her favorite television program. Teachers often use “time out” – placing an unruly child in temporary isolation to control disruptive behavior. Misbehaving teenagers are “grounded” by their parents. Hockey players are sent to the penalty box for fighting.

Punishment can produce unwanted consequences. The association between punishment and a particular act can generalize, so that when the undesirable behavior disappears, desirable behavior also vanishes. For example, a child who is regularly and severely punished for aggression may stop fighting but may also become passive, giving up assertiveness along with aggression.

When punishment takes the form of harsh criticism, it can have very negative emotional consequences, lowering self-esteem and eroding any sense of competence. In addition, punishment may lead, by association, to intense dislike and to the avoidance of whoever administrated the punishment as well as avoidance of the situation in which it occurred.

Although punishment clearly tells people what not to do, it gives no hint as to what they should do. It suppresses inappropriate behavior without establishing an appropriate response in its place. For this reason punishment is probably most effective when used in conjunction with positive reinforcement for a specific alternative behavior. Such a combination effectively ended a retarded boy’s painful attacks on other children in an institution. Each time Ricky bit another child, the staff made him wear a catcher’s mask for 10 minutes. The mask made it impossible for him to bite. Because Ricky disliked the face mask, he soon stopped his attacks. The staff also began rewarding Ricky with attention and approval whenever he played constructively with others for a certain length of time without biting.

Дата добавления: 2014-12-27