Classical conditioning (also Pavlovian conditioning or respondent conditioning) is a form of learning in which the conditioned stimulusor CS, comes to signal the occurrence of a second stimulus, the unconditioned stimulus or US. (A stimulus is a factor that causes a response in an organism.) The conditioned response is the learned response to the previously neutral stimulus. The US is usually a biologically significant stimulus such as food or pain that elicits a response from the start; this is called the unconditioned response or UR. The CS usually produces no particular response at first, but after conditioning it elicits the conditioned response or CR. Classical conditioning differs from operant or instrumental conditioning, in which behavior emitted by the subject is strengthened or weakened by its consequences (i.e. reward or punishment).
There are many examples of these innate (unconditioned) reflexes (corneal, coughing, swallowing, withdrawal reflexes etc.) or learned (conditioned) reflexes.p. 82
"In any animal, regardless of its prior history, painful stimulation of the foot causes the leg to be withdrawn by bending at all its joints. Thisflexor reflex is an example of an unconditioned reflex, an innate response based on fixed connections in the chain of neurons from the receptor (sensor) to the effector. Of still more interest in everyday life are the acquired or conditioned reflexes, in which the functional connections between the excited sensors and the patterns of activity in effector organs become established by learning process.":p. 155
Conditioning is usually done by pairing the two stimuli, as in Pavlov’s classic experiments. Pavlov presented dogs with a ringing bell followed by food. The food elicited salivation (UR), and after repeated bell-food pairings the bell also caused the dogs to salivate. In this experiment, the unconditioned stimulus is the dog food as it produces an unconditioned response, saliva. The conditioned stimulus is the ringing bell and it produces a conditioned response of the dogs producing saliva.
It was originally thought that the process underlying classical conditioning was one where the conditioned stimulus becomes associated with, and eventually elicits, the unconditioned response. But many observations do not support this hypothesis. For example, the conditioned response is often quite different from the unconditioned response. Learning theorists now more commonly suggest that the CS comes to signal or predict the US. In the case of the salivating dogs in Pavlov's experiment, the bell tone signaled and predicted the arrival of the dog food, thus resulting in the dog salivating.Robert A. Rescorla provided a clear summary of this change in thinking, and its consequences, in his 1988 article "Pavlovian conditioning: It's not what you think it is."
Positive reinforcement occurs when a response produces a stimulus and that response increases in probability in the future in similar circumstances.
Example: If a dog "sits" on command and this behavior is followed by the reward of a dog treat, then the dog treat serves to positively reinforce the behavior of "sitting."
Example: A father gives candy to his daughter when she picks up her toys. If the frequency of picking up the toys increases, the candy is a positive reinforcer (to reinforce the behavior of cleaning up).
Negative reinforcement occurs when a response produces the removal or avoidance of an aversive stimulus and that response increases in probability in the future in similar circumstances.[
Example: A child cleans his or her room, and this behavior is followed by the parent stopping "nagging" or asking the child repeatedly to do so. Here, the nagging serves to negatively reinforce the behavior of cleaning because the child wants to remove that aversive stimulus of nagging.
Example: A person puts ointment on a bug bite to soothe an itch. If the ointment works, the person will likely increase the usage of the ointment because it resulted in removing the itch, which is the negative reinforcer.
A primary reinforcer, sometimes called an unconditioned reinforcer, is a stimulus that does not require pairing to function as a reinforcer and most likely has obtained this function through the evolution and its role in species' survival. Examples of primary reinforcers include sleep, food, air, water, and sex. Some primary reinforcers, such as certain drugs, may mimic the effects of other primary reinforcers. While these primary reinforcers are fairly stable through life and across individuals, the reinforcing value of different primary reinforcers varies due to multiple factors (e.g., genetics, experience). Thus, one person may prefer one type of food while another abhors it. Or one person may eat lots of food while another eats very little. So even though food is a primary reinforcer for both individuals, the value of food as a reinforcer differs between them.
A secondary reinforcer, sometimes called a conditioned reinforcer, is a stimulus or situation that has acquired its function as a reinforcer after pairing with a stimulus that functions as a reinforcer. This stimulus may be a primary reinforcer or another conditioned reinforcer (such as money). An example of a secondary reinforcer would be the sound from a clicker, as used in clicker training. The sound of the clicker has been associated with praise or treats, and subsequently, the sound of the clicker may function as a reinforcer. As with primary reinforcers, an organism can experience satiation and deprivation with secondary reinforcers
Positive punishment occurs when a response produces a stimulus and that responses decreases in probability in the future in similar circumstances.
Example: A mother yells at a child when he or she runs into the street. If the child stops running into the street, the yelling acts as positive punishment because the mother presents (adds) an unpleasant stimulus in the form of yelling.
Negative punishment occurs when a response produces the removal of a stimulus and that response decreases in probability in the future in similar circumstances.
Example: A teenager comes home after curfew and the parents take away a privilege, such as cell phone usage. If the frequency of the child coming home late decreases, the removal of the phone is negative punishment because the parents are taking away a pleasant stimulus (the phone) and motivating the child to return home earlier.
Simply put, reinforcers serve to increase behaviors whereas punishers serve to decrease behaviors; thus, positive reinforcers are stimuli that the subject will work to attain, and negative reinforcers are stimuli that the subject will work to be rid of or to end. The table below illustrates the adding and subtracting of stimuli (pleasant or aversive) in relation to reinforcement vs. punishment.
Conditioning (or instrumental conditioning) is a type of learning in which an individual's behavior is modified by its consequences; the behaviour may change in form, frequency, or strength. Operant conditioning is a term that was coined by B. F. Skinner in 1937. The word operant refers to, "an item of behavior that is initially spontaneous, rather than a response to a prior stimulus, but whose consequences may reinforce or inhibit recurrence of that behavior".
Operant conditioning is distinguished from classical conditioning (or respondent conditioning) in that operant conditioning deals with the modification of "voluntary behaviour" or operant behaviour. Operant behavior operates on the environment and is maintained by its consequences, while classical conditioning deals with the conditioning of reflexive (reflex) behaviours which are elicited by antecedentconditions. Behaviours conditioned via a classical conditioning procedure are not maintained by consequences.
Behavior exhibits variability, sometimes one behavior occurs; at other times, other behaviors occur.
We want to know why a behavior increases or decreases in rate or probability. We want to know why we do what we do.
A revolutionary advance occurred when it was realized that not only will some stimuli elicit reflexive responses, but a stimulus such a a bell, preceding that elicitor will result in the bell coming to elicit salivation.
This demonstration banished forever the belief that only humans could adapt to their environment, while lower animals were governed only by inborn instincts. Learning occurs across a very broad range of animals. This was a far more seminal realization than his other Nobel prize winning work.
If we kicked a desk it would move. If we first yelled "lookout" then kicked the desk, it would similarly move. Suppose we then simply yelled "lookout"--- if the desk moved ---we would be amazed by the miraculous event. We should be no less amazed by a dog (or a human) salivating to a bell; they are both also part of the natural world. The burning question is why do living things adapt and how?
Thorndike drew attention to an equally significant phenomenon. The consequence of a behavior affects the future rate of that behavior. If a person tells a joke and receives laughter, then it is more likely that that person will tell another joke.
Skinner went on to emphasize the importance of antecedent stimuli in the control of operant behavior. It is particularly likely that the person will tell the joke when with the same group, rather than when with a totally different group of people or only an empty room.
Additionally Skinner realized that the most productive way to conceptualize stimuli and responses was in terms of their commonality of function. All behaviors which covary as the result of the same environmental changes should be seen as being in the same class. Likewise all stimuli which have the same impact on behavior can most productively be seen as equivalent to each other.
The major functional relationships in short-term behavioral adaptation are conceptualized as:
a. If a response is followed by a reinforcer in the presence of some stimulus class, then it is more likely that that behavior class will occur when similar stimuli are in effect in the future.
b. If a stimulus precedes an elicitor, then it is more likely that similiar stimuli when presented in the future, will be followed by a reaction related to that controlled by the eliciting stimulus.
Schedules of Reinforcement
A whole range of rules can govern the contingency between responses and reinforcement - these different types of rules are referred to as schedules of reinforcement. Most of these schedules of reinforcement can be divided into schedules in which the contingency depends on the number of responses and those where the contingency depends on their timing. When an animal's surroundings are controlled, its behavior patterns after reinforcement become predictable, even for very complex behavior patterns. A schedule of reinforcement is a rule or program that determines how and when the occurrence of a response will be followed by the delivery of the reinforcer, andextinction, in which no response is reinforced. Schedules of reinforcement influence how an instrumental response is learned and how it is maintained by reinforcement. Between these extremes is intermittent or partial reinforcement where only some responses are reinforced.
Specific variations of intermittent reinforcement reliably induce specific patterns of response, irrespective of the species being investigated (including humans in some conditions). The orderliness and predictability of behavior under schedules of reinforcement was evidence for B.F. Skinner's claim that by using operant conditioning he could obtain "control over behavior", in a way that rendered the theoretical disputes of contemporary comparative psychology obsolete. The reliability of schedule control supported the idea that a radical behavioristexperimental analysis of behavior could be the foundation for a psychology that did not refer to mental or cognitive processes. The reliability of schedules also led to the development of applied behavior analysis as a means of controlling or altering behavior.
Many of the simpler possibilities, and some of the more complex ones, were investigated at great length by Skinner using pigeons, but new schedules continue to be defined and investigated.
Animal Learning & Cognition
Animal cognition is the study of the mental capacities of animals. It has developed out ofcomparative psychology, including the study of animal conditioning and learning, but has also been strongly influenced by research inethology, behavioral ecology, and evolutionary psychology. The alternative name cognitive ethology is therefore sometimes used; much of what used to be considered under the title ofanimal intelligence is now thought of under this heading.
Research in animal cognition mostly concerns mammals, especially primates,cetaceans, and elephants, as well as dogs, cats, raccoons and rodents. However, research also extends to non-mammalian vertebrates such as birds including parrots,corvids, and pigeons, as well as to reptiles such as lizards and snakes, and to fish, even to invertebrates such as cephalopods, spiders, and insects.
Animals trained to discriminate between two stimuli, say black versus white, can be said to attend to the "brightness dimension," but this says little about whether this dimension is selected in preference to others. More enlightenment comes from experiments that allow the animal to choose from several alternatives. For example, several studies have shown that performance is better on, for example, a color discrimination (e.g. blue vs green) after the animal has learned another color discrimination (e.g. red vs orange) than it is after training on a different dimension such as an X shape versus and O shape. The reverse effect happens after training on forms. Thus, the earlier learning appears to affect which dimension, color or form, the animal will attend to.
Other experiments have shown that after animals have learned to respond to one aspect of the environment responsiveness to other aspects is suppressed. In "blocking", for example, an animal is conditioned to respond to one stimulus ("A") by pairing that stimulus with reward or punishment. After the animal responds consistently to A, a second stimulus ("B") accompanies A on additional training trials. Later tests with the B stimulus alone elicit little response, suggesting that learning about B has been blocked by prior learning about A . This result supports the hypothesis that stimuli are neglected if they fail to provide new information. Thus, in the experiment just cited, the animal failed to attend to B because B added no information to that supplied by A. If true, this interpretation is an important insight into attentional processing, but this conclusion remains uncertain because blocking and several related phenomena can be explained by models of conditioning that do not invoke attention
Associated URL: http://www.pigeon.psy.tufts.edu/psych26/default.htm
Development of Pecking in Ring Doves
The development of pecking in ring doves is described and analyzed as a model system for understanding the roles of learning in behavioral development. Ring dove squab go from complete dependence on their parents to independent feeding during the third and fourth week post-hatch. They learn to identify food and to consume it through their interaction with food and their parents. This chapter describes experiments that analyze the specific learning mechanisms involved in the development of pecking and what it is that squabs learn from their experience.
Tool use in animals
The study of tool use in animals illuminates similarities between humans and animals in terms of problem solving skills, dexterity, and intelligence. Benjamin Beck(1980) offers a fascinating story about the ingenuity of a crow which lived in his laboratory. The crow was fed dried mash, which needs to be moistened before the crow can eat it. However, the keepers occasionally forgot to do so. The crow found a solution to his keepers' absent-mindedness; he used a cup to get water to moisten the mash himself! The cup had been given to the crow as a toy but he used it to collect water from a trough on the other side of the room.
The anecdote about the crow offers an example of tool use in animals. The study of tool use in animals illuminates similarities between humans and animals in terms of problem solving skills, dexterity, and intelligence. Does the ability of animals to use tools signify an intelligence level close to that of humans? Many people define intelligence as the ability to adapt to your environment, or make your environment serve your purposes. Is animal tool use symbolic of that definition of intelligence? Tool use in primates is particularly interesting because it sheds light on the abilities and lifestyles of early humans.
Two characteristics of an environment are necessary to support the evolution of tool behaviors in animals. First of all, the use of tools must be advantageous to the animal. The examples which follow illustrate the advantages of tool use for the Egyptian vultures, chimpanzees, hooded monkeys, woodpecker finches, and green herons. Secondly, animal tool use is constrained by the availability of objects in the environment which make feasible tools. Without access to stones, poles, pieces of wood, and cactus spines, these animals would not have been able to acquire the uses of tools which they have.
Tool use is actually more prevalent in captive birds and mammals than in their wild counterparts. Of course, observation of tool use is much easier with captive animals. However, the more frequent use of tools in captive environments is supported even when an adjustment is made for this bias. The reason for higher rates of tool use in captive environments relates to environmental opportunity. Captive animals are relieved of many chores which they have in the wild because they are provided with adequate food and water, security from predators, and protection from environmental extremes such as weather. Moreover, captive animals are often provided with many manipulative objects.