Canine Behavior: Genetics, Operant Conditioning, and Learning

Introduction: The Nature vs. Nurture Debate

The debate over nature vs. nurture as it applies to learning dates back over a hundred years. During much of the 20th century, the distinction between learned and inherited behavior appeared much clearer than it does today. The concept that any type of behavior was either learned or developed without learning seemed a rational and straightforward belief. Research based on these expectations caused some scientists to conclude that rat-killing behavior among cats, for example, is a learned behavior rather than an instinctive one, that human fears are all acquired, or that intelligence is completely the result of experience. Learning theorists at this point argued that most behavior is learned and that biological factors are of little or no importance.

The behaviorist position — that human behavior could be explained entirely in terms of reflexes, stimulus-response associations, and the effects of reinforcers upon them, entirely excluding "mental" terms such as desires and goals — was advanced by J.B. Watson in his 1914 book, Behavior: An Introduction to Comparative Psychology. These early scientists routinely employed dogs in their research, with clear indications of learning behaviors taking place. However, the debate continues over just how much of this learning can be attributed to environmental factors and how much relates to instinctual behaviors. This paper examines the relevant scholarly literature concerning operant conditioning in general, and the extent to which it applies to dogs in particular, followed by a summary of the research in the conclusion.

The Human–Dog Bond: History and Anthrozoology

There has been a unique bond between humans and dogs throughout history that likely resulted because each species possessed certain characteristics that were equally beneficial to the survival of the other. Anyone who has ever owned a dog can attest to the powerful relationship that can develop between owner and canine. The answers to the "why" of dog ownership, for those who do not understand it, can be partly explained — at least in a clinical sense — by the long list of health factors associated with pet ownership and bonding. However, this relationship tends to be one-sided in many cases. "We have systematically, through seat-of-the-pants, applied genetics, been changing dogs. We have been modifying them to fit our immediate needs and even to fit our technology" (Dogs and People: The History and Psychology of a Relationship, 1996, p. 54). Human beings have played an instrumental role in creating dogs that fulfill specific needs. By applying the most primitive forms of genetic engineering, dogs have been bred to accentuate instincts that were evident from their earliest encounters with humans.

While details about the evolution of dogs remain unclear, the first dogs were hunters with keen senses of sight and smell; humans subsequently developed these instincts and created new breeds as need or desire arose over time (Dogs and People, 1996). Dogs were able to acquire food by scavenging the campsites of humans; humans could stay warmer in colder climates and have a live alarm system to warn them of predators by allowing dogs into their dwellings. This close bond between the two eventually grew stronger, gradually maturing into a relationship that was much less utilitarian and more focused on higher-level needs, such as companionship and emotional security (Wendt, 1996).

According to Dogs and People: The History and Psychology of a Relationship (1996), "There is a long-standing controversy as to where dogs come from. The current belief is that dogs started out originally as wolves. Early in our history we domesticated the wolf and that eventually became our pet dog" (p. 54). The study of such human-animal relations, known formally as anthrozoology, has seen an upsurge of interest in recent years, with researchers from many different academic fields contributing to creative studies involving the multiplicity of interactions between humans and dogs. Podberscek, Paul, and Serpell (2000) reviewed much of this work as it relates to relations between people and companion animals, and stated that the history of companionable human-animal interactions goes back to before the emergence of Homo sapiens as a distinct species. Human ancestors, Homo erectus, also lived in close relationship with the ancestors of modern dogs, Canis familiaris.

Furthermore, long before the conquest of the Americas by Europeans, Amazonian Indians are known to have lived with dogs as companion animals (Schwartz, 1997). At the same time, in pre-modern Europe, people of all classes also lived with dogs as companion animals (Thurston, 1996). Unfortunately, not all human-animal interactions have been so amicable. Animals have been used and abused by humans in various ways, which almost all people consider unjust and inhumane (Wendt, 1996), and behavioral scientists continue to prefer dogs, among other species, for research purposes today (Gormezano, Prokasy, & Thompson, 1987).

Operant Conditioning and Behaviorism

Instrumental, or operant, conditioning occurs when the presentation or withdrawal of a specific stimulus (i.e., a reinforcer or punisher) is made contingent upon an organism's specific response. Stimuli that tend to increase the rate or magnitude of a specified response — such as a food reward or the termination of a shock — are defined as reinforcers. By contrast, stimuli that decrease response rate or magnitude (e.g., the presentation of a loud noise or a shock) are termed punishers (Ader, Baum, & Weiner, 1988). In human operant conditioning studies in which feedback for making the specified response serves as the reinforcer, the procedure is known as biofeedback. While instrumental and classical conditioning are both forms of associative learning, instrumental conditioning differs procedurally in that reinforcement (e.g., presentation of the unconditioned stimulus) is contingent upon the making of a response specified by the experimenter (Ader, Baum, & Weiner, 1988).

Operant conditioning is the foundation on which B.F. Skinner explored behavior. According to Ellis (1999), Skinner was possibly the 20th century's most influential psychologist, and developed "operant conditioning, which is the systematic use of positive reinforcement to modify behavior" (p. 34). A wide range of animal training methods, parenting techniques, and incentive programs — including such common tactics as stock options, bonuses, and sales commissions — were all influenced by Skinner's concept (Ellis, 1999).

Skinner based his approach on Ivan Pavlov's systematic experimentation with conditioning. Pavlov supervised several physiological laboratories, of which the most prominent was the Imperial Institute of Experimental Medicine in St. Petersburg (Windholz, 1997). Between 1897 and 1936, at least 146 Pavlovians — graduate students and a few permanent coworkers — investigated animals' brain functions. "The Pavlovians usually experimented at Pavlov's behest, for he rarely experimented himself, preferring to supervise each experimenter's work. Breach of the specified experimental procedures evoked Pavlov's anger" (p. 942). Pavlov was profoundly influenced by Darwin's concept of the struggle for existence and its functionalistic implications.

In the 1890s, Pavlov speculated that the upper tract of animals' digestive systems responded functionally to specific foods — namely, a small salivary secretion to moist foods such as meat, and a larger salivary secretion to dry foods such as bread. Pavlov's student, S.G. Vul'fson, tested this hypothesis in 1897 at the Imperial Institute of Experimental Medicine (Windholz, 1997). In addition to finding experimental support for Pavlov's hypothesis, Vul'fson also determined, without intending to do so, that after eating moist and dry foods, dogs that were "teased" from afar by these foods responded with a corresponding but diminished salivary secretion (Windholz, 1997).

Salivation to stimuli presented at a distance was viewed as anomalous because, given the Cartesian conceptualization of reflexive action, an immediate contact between environmental agents and the organism's sensory receptors was required. "Pavlov realized that although salivation was of minor physiological importance in the animal's adjustment to the environment, it was, nevertheless, an observable response to stimuli" (Windholz, 1997, p. 943). In the initial Pavlovian salivary reflex conditioning experiments, the subjects used were restrained dogs; however, in the 1930s, Pavlov's laboratory obtained two chimpanzees for similar experimentation.

Pavlov was critical of Wolfgang Köhler's scholarly explanation of problem solving, and successfully replicated Köhler's experiment in which an ape had to reach a suspended bait by building a tower of different-sized boxes. Through observations of the ape's behavior, Pavlov noted that it took several months for the animal to solve this problem; the ape was required to move the boxes directly under the bait, arrange the boxes in vertical order with the larger below the smaller, and test the construction's stability by climbing on the uppermost box and moving back and forth. Pavlov called this process the "chaotic" method, which he believed to be identical to E.L. Thorndike's trial-and-error method (Windholz, 1997).

In Pavlov's view, any organism's fundamental responses to the external and internal environments are innately determined movements — the unconditioned reflexes — which, if complex, Pavlov termed "instincts." Pavlov subsequently identified several instincts, of which two were crucial to an individual's ontogenetic survival: (1) the alimentary instinct, which prompted the organism's food-seeking and eating behavior, and (2) the defensive instinct, which was aimed at avoiding noxious or harmful stimuli. "The sexual instinct enabled the phylogenetic continuity of the species" (Windholz, 1997, p. 946). When Pavlov observed the overall behaviors of animals in the laboratory, he identified significant individual differences — such as temperaments — comprised of three parameter characteristics of the nervous system: (1) the intensity or strength level of excitation and inhibition, (2) the interrelation between excitation and inhibition, and (3) the rapidity of the spread of these processes.

While permutations of these parameters could result in a variety of temperament types, Pavlov observed only four, which corresponded to Hippocrates's humors: choleric, melancholic, sanguine, and phlegmatic (Windholz, 1997). In Pavlov's view, the organism's unconditioned reflexes, generated in the subcortical regions of the brain, are evoked by direct or immediate contact with the external environment.

By contrast, the conditioned reflexes, established in the cortical regions of the brain, are evoked by signals emanating from the external environment and comprise the first signal system. Since the environment is constantly changing, the first signal system tends to correct the organism's adjustment through the acquisition and extinction of reactions to environmental signals; however, because the human environment is mostly social, adjustment can be facilitated by language, or by what Pavlov called the second signal system (Windholz, 1997).

In 1938, B.F. Skinner identified two types of learning: (1) respondent and (2) operant conditioning (Klein & Mowrer, 1989). The term "respondent conditioning" refers to the learning situation investigated by Pavlov: "The conditioned and unconditioned stimuli are paired, and the conditioned stimulus subsequently elicits the conditioned response. In this type of learning, the animal or human passively responds to an environmental stimulus" (Klein & Mowrer, 1989, p. 11). Such respondent behaviors are thought to be mostly internal responses in the form of emotional and glandular reactions to stimuli; however, Skinner was primarily interested in operant conditioning. He maintained that in operant conditioning, an animal or human actively interacts with its environment in order to obtain a reward. "Operant behavior is not elicited by a stimulus: rather, in anticipation of the consequences of the behavior, an animal or person voluntarily performs a specific behavior if that behavior has previously produced reinforcement" (Klein & Mowrer, 1989, p. 11). Skinner termed this relationship between behavior and reinforcement a "contingency"; the environment determines contingencies, and the animal or human must perform the appropriate behavior in order to obtain a reinforcer.

Edward L. Thorndike's study of instrumental conditioning showed that animals can learn how to perform certain tasks that provide them with some type of reward (Brush, Overmier, & Solomon, 1985). Thorndike's methods were further refined by B.F. Skinner; the "Skinner Box" provided researchers with yet another tool for examining the relationship between stimulus and operant conditioning. Similar to classical conditioning, operant conditioning examines the response of the learner following a stimulus; however, here the response is voluntary and the concept of reinforcement is emphasized.

From the 1930s to the late 1960s, behavior theorists developed global theories of learning — that is, theories that attempted to explain all aspects of the learning process. While this approach provided much information about learning, more contemporary theorists investigate and describe specific aspects of the learning process (Klein & Mowrer, 1989). John B. Watson was an American psychologist responsible for codifying and publicizing behaviorism. From Watson's perspective, behaviorism was an approach to psychology restricted to the objective, experimental study of the relations between environmental events and human behavior.

According to Klein and Mowrer (1989), behaviorism is a school of psychology that emphasizes the role of experience in governing human behavior. According to behaviorists, organisms possess instinctual motives; however, the important determinants of behavior are learned. "Acquired drives typically motivate us; our actions in response to these motives are also learned through our interaction with the environment" (Klein & Mowrer, 1989, p. 4). For instance, a behaviorist would assume that an individual's motivation to attend school is a learned one, and that behaviors while attending school are also learned. One main goal of the behaviorist, then, was the delineation of the laws governing learning — an issue that dominated academic psychology for generations. For much of the 20th century, behaviorists proposed a number of global explanations of learning; that is, a single view that could account for the learning of all behaviors (Klein & Mowrer, 1989).

Conclusion

The research showed that the bond between dogs and mankind extends back into the mists of time, but that this relationship has not always been mutually beneficial. Dogs have been and continue to be favorite laboratory test animals for many scientists, causing much backlash from animal rights activists. The value of findings from research conducted using dogs has also been questioned; nevertheless, the results of such studies show that dogs are much like people when it comes to the relationship between learning and reinforcement. Both dogs and humans are able to recognize that in some cases there is simply no relationship between behavior and reinforcement — a situation that has been shown to lead to feelings of helplessness and depression. Despite these constraints, the research also showed that operant conditioning has been used with great success in some settings, leading researchers to believe that there is more to nurture than to nature in this enduring debate.