Basic for any understanding of the apparent complexities of sexual behavior is the issue of how learning can modify the stimulus control of that behavior. Of equal importance is the issue of how learning may modify the motor patterns leading to sexual reward. The role of learning for sexual behaviors becomes paramount as soon as we want to understand human sexual behaviors, but it may also have considerable importance for non-human mammals. In this chapter, I try to show that the execution of sexual acts, more precisely acts involving genital stimulation, is involved in both classical conditioning and operant learning. Moreover, sexual responses and the stimuli controlling them may be the subject of non-associate forms of learning, notably habituation. The role of non-associative learning will also be mentioned. In the human, social learning is the main determinant of sexual behaviors, both with regard to the stimulus control of these behaviors and with regard to the motor patterns involved. I will introduce the fundamental principles of social learning and add a few words about its crucial role.
Classical conditioning, usually understood as a learning process by which one stimulus acquires the capacity to replace another, is the main process involved in modifications of the stimulus control of sexual activities in non-human mammals. In primary classical conditioning, the unconditioned stimulus, a stimulus that spontaneously activates a behavior, becomes associated with a previously neutral stimulus because of repeated presentations of the two stimuli in conjunction. A simple example may be a light that is presented to a hungry rat for a few seconds before a food pellet appears in the food cup. Initially, the rat will show no reaction to the light, more than perhaps a simple orienting reaction, i.e. turning the head toward the stimulus and looking at it. The food pellet, however, causes the rat to approach the food cup and subsequently ingest the pellet. When the light has preceded the food pellet a sufficient number of times, the rat will approach the food cup as soon as the light appears. The light has become a conditioned stimulus, evoking an important part of the response, approach, previously evoked only by the unconditioned stimulus, the food pellet. The light has replaced the food pellet as the stimulus causing the rat to display the behavior pattern of approach. We already know that any stimulus activating approach behaviors is a positive incentive. The neutral light stimulus has become a positive incentive because of classical conditioning. Instead of a light, any neutral stimulus could have been presented for a few seconds before delivery of the food pellet, like a tone or an odor. Likewise, instead of using food to a hungry rat as the unconditioned stimulus, we could have used water to a thirsty rat or any other stimulus causing approach without previous learning. A sexual example would be to make a light precede the appearance of a sexually receptive female rat to a male. After a sufficient number of pairings of the light and the unconditioned sexual incentive of a female, the light should acquire sexual incentive properties.
Rather than replacing one stimulus with another through the process of classical conditioning, we may arrange a situation such that an act produces a desirable stimulus. A hungry rat may be put into a cage where a nose poke in a small opening in the upper right corner produces delivery of a food pellet at the bottom of the opposite corner. If this occurs for a sufficient number of times, that rat will immediately put her nose in the opening when introduced into the cage after a couple of hours of food deprivation. In other words, an act, in this case poking the nose in a hole at the upper right corner of the cage, which produces a desirable consequence, in this case a food pellet, tends to be repeated with increasing frequency. We say that the rat has learned to nose poke. This kind of conditioning, in which the execution of a motor pattern precedes a desirable stimulus or event, is called operant conditioning.
Any event or stimulus able to enhance the probability of repetition of the act immediately preceding its appearance is called a reinforcer. Whether a stimulus or event has the quality of being a reinforcer or not can only be determined by observing its behavioral consequences. The circularity of the definition of a reinforcer has been the subject of much debate over the years, but learning theorists have long since solved the problem. We do not care about that here. What we have to care about, though, is the distinction between a reinforcer and a reward. That distinction is not always made, and the reason for this confusion can be attributed to Thorndike. The great learning theorist considered the terms reinforcement and reward as synonyms (Thorndike, 1932). However, reinforcement refers to effects on learning. The stimulus (e.g. food) or event (e.g. access to a new space) enhances the probability that the act producing it will be repeated. Each time a reinforcer appears, learning is strengthened, reinforced. Reward refers to some kind of affective response to the stimulus or event and has no obligatory relationship to learning. The distinction between reward and reinforcement has been brilliantly analyzed in a somewhat old paper (White, 1989). In most cases, a stimulus or event having the property of rein-forcer also has the property of reward, but there is no necessary or logical association. This makes it important to evaluate both the affective reactions produced by a stimulus or event and the effects it may have on learning. We will see that there are experimental procedures for doing that.
Classical and operant conditioning are two forms of associative learning. In classical conditioning, one stimulus is associated with another and in operant conditioning, an act is associated with an outcome. Besides associative learning, there are non-associate forms of learning. One of these is called habituation, which is usually defined as a reduction of the intensity of a response or of the probability of appearance of the response as a consequence of repeated presentations of a constant stimulus. The reduction must be a result of processes within the central nervous system, independent of adaptation in the sensory organs or fatigue in the effector systems. A typical example of habituation is our response to a loud noise. The first time we hear an unexpected, loud noise from a construction across the street we normally jump but, if the same noise is repeated a hundred times within one hour, we will no longer react to it. This lack of reaction is neither because I cannot hear it, nor because I am tired of jumping.
Instead of habituating to a constant stimulus, some people react in the opposite way. When my neighbor turns on his unpleasant music, a collection of Norwegian folk music tunes where the violins whine in a manner extremely aggressive to the human ear, I may not react for the first 15 minutes. Then I start to feel anxious and an intense activity in my sympathetic nervous system is evident. If it does not stop within another 15 minutes, I knock at the neighbor's door and ask him to turn the noise off. My reaction to a constant stimulus increased with repeated exposure. Please observe that all the folk music tunes sound identical to any non-expert, thereby satisfying the criterion of constant stimulus. This kind of learning is called sensitization. Another form of sensitization is observed when a completely irrelevant but strong or noxious stimulus is presented. The most famous case is certainly the enhanced gill and siphon withdrawal observed in response to a water jet in the sea hare, Aplysia californica, when a weak electric shock is applied to the head or tail.
The last form of learning I want to mention is the least understood. It is called social learning and is characterized by modifications of behavior as a result of social interactions, including observations of the behavior of other individuals, and in the absence of reinforcement. One form of social learning is called observational learning. It consists of observing someone and copying her behavior. A couple of conditions need to be satisfied if observational learning is to occur. These include the rather obvious necessity of paying attention to the person being observed and a detailed retention of the observed behavior in memory. The observer must also have the motor capacities for a replication of the behavior that was observed. This is not enough, though, for the socially learned behavior to manifest itself. Appropriate motivation is necessary and appropriate circumstances are required. A simplistic example may illustrate some of these principles. Imagine that we come to an airport for the first time in life. We are obviously overloaded with heavy luggage and we have no idea of what to do. In order to find out, we start to observe what other people do. We notice that most people entering the departure hall walk straight up a flight of stairs carrying their suitcases. A common reaction would be to suppose that the check-in counters are located on a higher level of the departure hall. We start to walk toward the stairs, only to find out that our suitcases were heavier than our muscle strength could cope with. We had paid attention, we had memorized, we had the motivation and the appropriate context, but not the motor capacities to execute the behavior pattern we had acquired through social learning.
It is not necessary directly to observe other, living people for acquiring knowledge by social learning. Instead of watching a living person we can watch, for example, a pornographic movie and acquire the behavior patterns shown there through social learning, or we can read a pornographic novel and do likewise.
Learning specialists know a lot with regard to both classical and operant conditioning. They know, for example, that both these forms of learning are as important in the human as in other mammals. They also know a lot about reinforcement and how to arrange reinforcement in relation to the preceding act in order to maximize the rapidity of learning, or maximize the amount of effort expended for getting the reinforcement, or how to make the learned act particularly resistant to extinction, and many other things. Habituation and sensitization are also quite well known. Social learning is the least understood of all forms of learning and it is probably of limited importance for non-human sexual behaviors. On the contrary, human sexuality is heavily determined by social learning, as pointed out already. Anyone interested in learning more about learning should consult any current textbook, of which there are plenty. The subject is fascinating indeed but, despite this fact, I will not enter into any elaborate analysis of learning theory. This brief and probably wanting introduction is enough for our purposes.
Was this article helpful?