Conditioned emotional response

Last updated

The term conditioned emotional response (CER) can refer to a specific learned behavior or a procedure commonly used in classical or Pavlovian conditioning research. It may also be called "conditioned suppression" or "conditioned fear response (CFR)." [1] It is an "emotional response" that results from classical conditioning, usually from the association of a relatively neutral stimulus with a painful or fear-inducing unconditional stimulus. As a result, the formerly neutral stimulus elicits fear. For example, if seeing a dog (a neutral stimulus) is paired with the pain of being bitten by the dog (unconditioned stimulus), seeing a dog may become a conditioned stimulus that elicits fear (conditioned response).

Contents


Experimentation

In 1920 John B. Watson and Rosalie Rayner demonstrated such fear conditioning in the Little Albert experiment. They started with a 9-month boy called "Albert", who was unemotional but was made to cry by the loud noise (unconditioned stimulus) of a hammer striking a steel bar. Albert initially showed no fear of a white rat (neutral stimulus), but after the sight of the rat had been accompanied five times by the loud noise, he cried and tried to escape the rat, showing that the rat had become a conditioned stimulus for fear. Although the Watson and Rayner work with Little Albert clearly falls under the broad umbrella of "conditioned fear" they did not use the term CER and thought they were applying more general conditioning principles to human behavior.

In 1941 B.F. Skinner and William Kaye Estes were the first to use the term "CER" and demonstrated the phenomenon with rats. [2] They trained food-deprived rats to lever-press (operant conditioning) for food pellets, maintained on a variable interval (VI) schedule of reinforcement. Periodically, a tone was presented, for a brief amount of time, which co-terminated with electric shock to the metal floor (classical delay conditioning). The rats, upon receipt of the first shock, displayed the expected unconditional responses to the shock (e.g., jumping, squealing, urinating, etc.), however with subsequent presentations of the tone-shock trials, those responses habituated somewhat. The largest change in behavior occurred during the time the tone was presented. That is, lever-pressing during the tone reduced to near zero levels. Given that the tone-shock pairings were likely sufficient to produce classical conditioning, Estes and Skinner hypothesized that the tone elicited fear that interfered or interrupted ongoing operant behavior. In a sense, the now CS (tone) "paralyzed in fear" the rat. Note that the suppression of lever-pressing was robust, even though the operant, lever-press - food contingency was not altered at all. This experiment is critical in experimental psychology for it demonstrated that the interaction of classical and operant conditioning contingency could be powerful in altering behavior. This work sparked a number of experiments on this interaction, resulting in important experimental and theoretical contributions on autoshaping, negative automaintenance, and potentiated feeding, to name a few.

More importantly, the CER procedure solved a serious experimental problem in classical conditioning. In Pavlov's original demonstration of classical conditioning, he used a backward conditioning arrangement as the control condition. Briefly, in that procedure, the dogs experienced the same number of US presentations (food) and the same number of CS presentations (metronome ticking) as the experimental groups, but the timing of the CS and US presentations were reversed. The US preceded the CS, rather than the other way around. In the backward conditioning control procedure popular with Pavlov, his dogs did not salivate to the presentation of the CS, in contrast to those that received forward conditioning. However, the dogs did learn something - the presentation of the metronome predicted the absence of the food. This phenomenon we now call "conditioned inhibition." However, since Pavlov was studying conditioned excitation, by measuring drops of saliva, he could not experimentally measure the inhibition of salivation. There was a floor effect as the dogs could not salivate below 0 drops of saliva. Thus, the lack of salivation by Pavlov's dogs led him to conclude that no conditioning resulted, however, he could not measure conditioning. The CER procedure obviates this problem because conditioning is typically measured with a "suppression ratio", the ratio of responding during the CS period relative to a period of equal length but without the CS (usually immediately prior to the presentation of the CS). A measure of 0.5 indicates no conditioning, while measures that deviate from 0.5 reflect effective conditioning, relatively (0 is indicative of asymptotic conditioning). CER can, therefore, measure both conditioned excitation and conditioned inhibition.

Neurological Origin

The amygdala, located in the temporal lobe, is a key brain region involved in the conditioned fear response and contributes to the autonomic, hormonal, and behavioral factors associated with that response. According to studies by Coover, Murison, & Jellestad and Davis and LeDoux in 1992, when a dog's amygdala is damaged, it does not show fear, and, when tamed by human beings, the dog's stress hormone levels in the blood are lower than they are in a normal dog. Similarly, humans become less likely to report feelings of fear after their amygdala has been damaged due to injury or stroke.

The most common measure of the CFR is the suppression ratio.

See also

Related Research Articles

<span class="mw-page-title-main">Ivan Pavlov</span> Russian physiologist (1849–1936)

Ivan Petrovich Pavlov, was a Russian and Soviet experimental neurologist, psychologist and physiologist known for his discovery of classical conditioning through his experiments with dogs.

Operant conditioning, also called instrumental conditioning, is a learning process where behaviors are modified through the association of stimuli with reinforcement or punishment. In it, operants—behaviors that affect one's environment—are conditioned to occur or not occur depending on the environmental consequences of the behavior.


Classical conditioning is a behavioral procedure in which a biologically potent physiological stimulus is paired with a neutral stimulus. The term classical conditioning also refers to the subject animal's learning from the pairing of a physiologic stimulus with a neutral stimulus, which elicits the required response from the neutral stimulus rather than the physiological stimulus.

In behavioral psychology, reinforcement is a consequence applied that will strengthen an organism's future behavior whenever that behavior is preceded by a specific antecedent stimulus. This strengthening effect may be measured as a higher frequency of behavior, longer duration, greater magnitude, or shorter latency.

The experimental analysis of behavior is a science that studies the behavior of individuals across a variety of species. A key early scientist was B. F. Skinner who discovered operant behavior, reinforcers, secondary reinforcers, contingencies of reinforcement, stimulus control, shaping, intermittent schedules, discrimination, and generalization. A central method was the examination of functional relations between environment and behavior, as opposed to hypothetico-deductive learning theory that had grown up in the comparative psychology of the 1920–1950 period. Skinner's approach was characterized by observation of measurable behavior which could be predicted and controlled. It owed its early success to the effectiveness of Skinner's procedures of operant conditioning, both in the laboratory and in behavior therapy.

<span class="mw-page-title-main">Fear conditioning</span> Behavioral paradigm in which organisms learn to predict aversive events

Pavlovian fear conditioning is a behavioral paradigm in which organisms learn to predict aversive events. It is a form of learning in which an aversive stimulus is associated with a particular neutral context or neutral stimulus, resulting in the expression of fear responses to the originally neutral stimulus or context. This can be done by pairing the neutral stimulus with an aversive stimulus. Eventually, the neutral stimulus alone can elicit the state of fear. In the vocabulary of classical conditioning, the neutral stimulus or context is the "conditional stimulus" (CS), the aversive stimulus is the "unconditional stimulus" (US), and the fear is the "conditional response" (CR).

<span class="mw-page-title-main">Behaviorism</span> Systematic approach to understanding the behavior of humans and other animals

Behaviorism is a systematic approach to understanding the behavior of humans and other animals. It assumes that behavior is either a reflex evoked by the pairing of certain antecedent stimuli in the environment, or a consequence of that individual's history, including especially reinforcement and punishment contingencies, together with the individual's current motivational state and controlling stimuli. Although behaviorists generally accept the important role of heredity in determining behavior, they focus primarily on environmental events.

<span class="mw-page-title-main">Shaping (psychology)</span> Psychological paradigm for behavior analysis

Shaping is a conditioning paradigm used primarily in the experimental analysis of behavior. The method used is differential reinforcement of successive approximations. It was introduced by B. F. Skinner with pigeons and extended to dogs, dolphins, humans and other species. In shaping, the form of an existing response is gradually changed across successive trials towards a desired target behavior by reinforcing exact segments of behavior. Skinner's explanation of shaping was this:

We first give the bird food when it turns slightly in the direction of the spot from any part of the cage. This increases the frequency of such behavior. We then withhold reinforcement until a slight movement is made toward the spot. This again alters the general distribution of behavior without producing a new unit. We continue by reinforcing positions successively closer to the spot, then by reinforcing only when the head is moved slightly forward, and finally only when the beak actually makes contact with the spot. ... The original probability of the response in its final form is very low; in some cases it may even be zero. In this way we can build complicated operants which would never appear in the repertoire of the organism otherwise. By reinforcing a series of successive approximations, we bring a rare response to a very high probability in a short time. ... The total act of turning toward the spot from any point in the box, walking toward it, raising the head, and striking the spot may seem to be a functionally coherent unit of behavior; but it is constructed by a continual process of differential reinforcement from undifferentiated behavior, just as the sculptor shapes his figure from a lump of clay.

Extinction is a behavioral phenomenon observed in both operantly conditioned and classically conditioned behavior, which manifests itself by fading of non-reinforced conditioned response over time. When operant behavior that has been previously reinforced no longer produces reinforcing consequences the behavior gradually stops occurring. In classical conditioning, when a conditioned stimulus is presented alone, so that it no longer predicts the coming of the unconditioned stimulus, conditioned responding gradually stops. For example, after Pavlov's dog was conditioned to salivate at the sound of a metronome, it eventually stopped salivating to the metronome after the metronome had been sounded repeatedly but no food came. Many anxiety disorders such as post traumatic stress disorder are believed to reflect, at least in part, a failure to extinguish conditioned fear.

An avoidance response is a natural adaptive behavior performed in response to danger. Excessive avoidance has been suggested to contribute to anxiety disorders, leading psychologists and neuroscientists to study how avoidance behaviors are learned using rat or mouse models. Avoidance learning is a type of operant conditioning.

<span class="mw-page-title-main">Avoidance response</span>

An avoidance response is a response that prevents an aversive stimulus from occurring. It is a kind of negative reinforcement. An avoidance response is a behavior based on the concept that animals will avoid performing behaviors that result in an aversive outcome. This can involve learning through operant conditioning when it is used as a training technique. It is a reaction to undesirable sensations or feedback that leads to avoiding the behavior that is followed by this unpleasant or fear-inducing stimulus.

<span class="mw-page-title-main">Neutral stimulus</span> Stimulus initially producing no specific response

A neutral stimulus is a stimulus which initially produces no specific response other than focusing attention. In classical conditioning, when used together with an unconditioned stimulus, the neutral stimulus becomes a conditioned stimulus. With repeated presentations of both the neutral stimulus and the unconditioned stimulus, the neutral stimulus will elicit a response as well, known as a conditioned response. Once the neutral stimulus elicits a conditioned response, the neutral stimulus becomes known as a conditioned stimulus. The conditioned response is the same as the unconditioned response, but occurs in the presence of the conditioned stimulus rather than the unconditioned stimulus.

In psychology, a stimulus is any object or event that elicits a sensory or behavioral response in an organism. In this context, a distinction is made between the distal stimulus and the proximal stimulus.

Sensory preconditioning is an extension of classical conditioning. Procedurally, sensory preconditioning involves repeated simultaneous presentations (pairing) of two neutral stimuli, i.e. stimuli that are not associated with a desired unconditioned response.

In experimental psychology the term conditioned emotional response refers to a phenomenon that is seen in classical conditioning after a conditioned stimulus (CS) has been paired with an emotion-producing unconditioned stimulus (US) such as electric shock. The conditioned emotional response is usually measured through its effect in suppressing an ongoing response. For example, a rat first learns to press a lever through operant conditioning. Classical conditioning follows: in a series of trials the rat is exposed to a CS, often a light or a noise. Each CS is followed by the US, an electric shock. As an association between the CS and US develops, the rat slows or stops its lever pressing when the CS comes on. The slower the rat presses, the stronger its conditioned emotional response, or "fear."

Discrimination learning is defined in psychology as the ability to respond differently to different stimuli. This type of learning is used in studies regarding operant and classical conditioning. Operant conditioning involves the modification of a behavior by means of reinforcement or punishment. In this way, a discriminative stimulus will act as an indicator to when a behavior will persist and when it will not. Classical conditioning involves learning through association when two stimuli are paired together repeatedly. This conditioning demonstrates discrimination through specific micro-instances of reinforcement and non-reinforcement. This phenomenon is considered to be more advanced than learning styles such as generalization and yet simultaneously acts as a basic unit to learning as a whole. The complex and fundamental nature of discrimination learning allows for psychologists and researchers to perform more in-depth research that supports psychological advancements. Research on the basic principles underlying this learning style has their roots in neuropsychology sub-processes.

Many experiments have been done to find out how the brain interprets stimuli and how animals develop fear responses. The emotion, fear, has been hard-wired into almost every individual, due to its vital role in the survival of the individual. Researchers have found that fear is established unconsciously and that the amygdala is involved with fear conditioning.

External inhibition is the observed decrease of the response of a conditioned reaction when an external (distracting) stimulus that was not part of the original conditioned response set is introduced. This effect was first observed in Ivan Pavlov's classical conditioning studies where the dogs would salivate less when presented with the sound of the tuning fork in the distracting context of a passing truck. External inhibition is important for its main principle in classical conditioning where a conditioned response may decrease in magnitude after the external stimulus is introduced. This is especially advantageous for when trying to disassociate conditioned stimulus and responses. A practical example is where students who become anxious upon standing in front of the class to give a presentation may feel less anxiety if their friends were sitting in front of the student presenting. The positive association of speaking to friends may distract the student from associating speaking to the entire class with anxiety.

Pavlovian-instrumental transfer (PIT) is a psychological phenomenon that occurs when a conditioned stimulus that has been associated with rewarding or aversive stimuli via classical conditioning alters motivational salience and operant behavior. Two distinct forms of Pavlovian-instrumental transfer have been identified in humans and other animals – specific PIT and general PIT – with unique neural substrates mediating each type. In relation to rewarding stimuli, specific PIT occurs when a CS is associated with a specific rewarding stimulus through classical conditioning and subsequent exposure to the CS enhances an operant response that is directed toward the same reward with which it was paired. General PIT occurs when a CS is paired with one reward and it enhances an operant response that is directed toward a different rewarding stimulus.

Association in psychology refers to a mental connection between concepts, events, or mental states that usually stems from specific experiences. Associations are seen throughout several schools of thought in psychology including behaviorism, associationism, psychoanalysis, social psychology, and structuralism. The idea stems from Plato and Aristotle, especially with regard to the succession of memories, and it was carried on by philosophers such as John Locke, David Hume, David Hartley, and James Mill. It finds its place in modern psychology in such areas as memory, learning, and the study of neural pathways.

References

  1. Carlson, Neil (2010). Psychology the Science of Behaviour [4th Canadian ed.] Toronto, On. Canada: Pearson Canada Inc. p. 423. ISBN   978-0-205-64524-4.
  2. Principles of Learning and Behavior by Michael P. Domjan