Elicited Behaviors Reflexes Reflexes are the most basic

Elicited Behaviors

Reflexes • Reflexes are the most basic form of elicited behavior. • A reflex is a relatively simple, automatic response to a stimulus. • (It can also be defined as the relationship between such a response and the stimulus that elicits it. )

• Some reflexes involve only one gland or set of muscles, such as when you salivate in response to a drop of lemon juice or blink in response to a puff of air. • Other reflexes are more general in scope, involving the coordinated action of several body parts.

For example, the startle response! • defensive reaction to a sudden, unexpected stimulus. • involves the automatic tightening of skeletal muscles as well as various hormonal and visceral (internal organ) changes.

• Similarly, the orienting response • in which we automatically position ourselves to facilitate attending to a stimulus • can involve a relatively major body movement, such as when we automatically turn in response to an unfamiliar noise behind us. • Many reflexes are closely tied to survival.

• vomiting reflex Ø flexion response Ø Newborns come “prepackaged” with a host of reflexes

• Many of the simpler refl exes are activated through a reflex arc. • For example, when you quickly jerk your hand away from an open flame, you are exhibiting a flexion response.

• Classical conditioning is a process in which one stimulus that does not elicit a response is associated with a second stimulus that does; as a result, the first stimulus also comes to elicit a response.

Pavlov’s Discovery of Classical Conditioning • Pavlovian conditioning • Ivan P. Pavlov (1849– 1936), a Russian physiologist, is generally credited with the first systematic investigations into classical conditioning

Basic Procedure and Definitions • To illustrate the process of classical conditioning, we will use one of Pavlov’s basic procedures. In this procedure, a dog is trained to salivate to the sound of a metronome.

Pavlov’s basic procedure worked as follows: • Before conditioning, the dogs would automatically salivate in response to the taste of food. • Because salivation to food occurs naturally and does not require prior training (conditioning), it is called an unconditioned response (UR)

• and the food is called an unconditioned stimulus (US).

• The sound of a metronome, however, does not elicit salivation and is therefore said to be a neutral stimulus (NS)

• During conditioning, the sound of the metronome is presented just before the food, which of course continues to elicit salivation. • After conditioning, as a result of having been paired with the food, the metronome itself now elicits salivation.

• Because salivating to the metronome requires prior training (conditioning), it is called a conditioned response (CR) • and the sound of the metronome is called a conditioned stimulus (CS)

Each pairing of the NS and US during conditioning is called a conditioning Trial Several conditioning trials are often needed before the NS becomes established as a CS. As an everyday example of classical conditioning, let us suppose that a child is bitten by a dog and subsequently develops a fear of dogs.

• This process can be diagrammed as follows

• The bite can be considered an unconditioned stimulus that elicits an unconditioned response of fear • As a result of the bite, the sight of the dog becomes a conditioned stimulus that elicits in the child a conditioned response of fear.

• The unconditioned stimulus (US) is a stimulus that naturally elicits a response, and the unconditioned response (UR) is the response that is naturally elicited by the US. • When we say that the response is naturally elicited by the US, we mean that it is an unlearned or innate reaction to that stimulus. For example, food naturally elicits the response of salivation, and a bite naturally elicits the response of fear (and pain).

• The conditioned stimulus (CS) is any stimulus that, although initially neutral, comes to elicit a response because it has been associated with an unconditioned stimulus. • The metronome is initially neutral with respect to salivation in that it does not naturally elicit salivation

• The metronome is initially neutral with respect to salivation in that it does not naturally elicit salivation • The conditioned response (CR) is the response, often similar to the UR, that is elicited by the CS.

• Note that the conditioned response is at most only similar to the unconditioned response. • It is never identical

• Even when the UR and CR appear identical, as in the case of salivation elicited by the food (US) and by the metronome (CS), there always some differences. • For example, the CR is usually weaker or less intense than the UR. Thus, the dog will salivate less to the metronome than it will to the food.

• The CR is also sometimes quite different from the UR. • For example, as noted earlier, the unconditioned response elicited by a bite is actually somewhat different from the conditioned response elicited by the sight of the dog that bit us.

• For simplicity, we labeled both responses as fear responses. Nevertheless, the response to the bite is mostly what we would describe as a pain reaction (“Yeow!”), whereas the subsequent response to the dog is one that is more clearly identified as fear

Appetitive and Aversive Conditioning • Most classical conditioning procedures can be divided into two categories based on whether the US is pleasant or unpleasant.

• In appetitive conditioning, the US is an event that is usually considered pleasant and that an organism seeks out. • In aversive conditioning, the US is an event that is usually considered unpleasant and that an organism usually avoids.

• Given how easily aversive conditioning can occur, it is not surprising that this type of conditioning probably accounts for many of our fears and anxieties.

• When the fear is appropriate—as in learning to fear an angry dog that has bitten us—such conditioning is beneficial. • When the fear is inappropriate—as when we begin to fear all dogs—such conditioning can be problematic.

• An ingenious solution to this problem was developed by Estes and Skinner (1941); it is known as the conditioned suppression or conditioned emotional response (CER) paradigm.

• In this paradigm, the rat is first trained to engage in some ongoing behavior, such as lever pressing to obtain food (with many lever presses being required to obtain a single pellet). • When a steady rate of lever pressing has been established, a fear-conditioning procedure is introduced in which, say, a 30 -second tone is presented followed by a 1 -second shock.

• Thus, the degree to which lever pressing for food is suppressed in the presence of the 30 second tone can be used as an indirect measure of the extent to which the tone elicits fear. • On a more formal level, conditioned suppression is measured in the form of a suppression ratio.

For example, imagine that a rat emits 20 responses during the 30 -second pre-CS period followed by 0 responses during a 30 -second CS period. In other words, there is total suppression of responding during the CS period. The suppression ratio would be: Thus, a suppression ratio of 0 indicates total suppression of responding. But what if instead there was only a partial suppression of responding during the CS? For example, what if the rat emitted 10 responses during the CS period? In this case, the suppression ratio would be To keep it straight, simply remember that a lower ratio indicates less responding, and less responding indicates greater suppression.

Excitatory and Inhibitory Conditioning • Conditioning in which the NS is associated with the presentation of a US is known as excitatory conditioning. • Conditioning in which the NS is associated with the absence or removal of a US is known as inhibitory conditioning.

• The result of inhibitory conditioning is that the CS comes to inhibit the occurrence of a certain response—that is, the response is less likely to occur when that stimulus is present.