Pavlov's Dogs Trivia Quiz

Answer: Physiology

In 1904, Ivan Pavlov was awarded a Nobel prize for Physiology and Medicine because of the research he had conducted, starting in 1890. In a 1927 series of lectures, Pavlov specifically called into question the concept that psychology could be called a science with the same standing as the natural sciences.

He somewhat disingenuously stated a hope that the physiological insights he and others had made might one day provide a factual basis for the development of a science of psychology. He had been investigating several aspects of dog physiology, including the digestive process.

It was in the process of investigating the relationship between the nervous system and the dog's autonomic bodily functions in the digestive process that he began his most famous series of experiments.

At the time of his experiments, he was in charge of the Department of Physiology at the Institute of Experimental Medicine in St. Petersburg.

Answer: Rene Descartes

In "Discourse on Method", Rene Descartes distinguished between humans (with a soul) and animals, whose behavior could be explained in terms of purely physical principles. His investigations were based on dissection, and he called for better medical investigation into structure and function of the organs of humans as well as of animals.

As he explained the concept of the reflex, an external stimulus hits some nervous receptor, which produces a nervous impulse. The nervous impulse is transmitted through the nervous system to some site in the central nervous system where its interactions with previously-established nervous connections cause a responding impulse to be transmitted out to the appropriate organ, where the active response is observed. Pavlov's interest lay in the processing stage, and how a given stimulus is, or becomes, linked to a specific response.

Answer: Salivary reflex

The reflex secretion of saliva was chosen for a number of reasons. Because the amount of saliva produced (and the rate of production) can be readily measured, it provides a way to quantify the response. Also a significant consideration was the ease of producing a stimulus that would excite this reflex.

Pavlov prided himself on the development of techniques that would allow the investigation of processes in functioning animals, rather than those relying on vivisection. However, there was still some surgical invasion. In his own words, "For the purpose of registering the intensity of the salivary reflex all the dogs employed in the experiments are subjected to a preliminary minor operation, which consists in the transplantation of the opening of the salivary duct from its natural place on the mucous membrane of the mouth to the outside skin. For this purpose the terminal portion of the salivary duct is dissected and freed from the surrounding tissue, and the duct, together with a small portion of the mucous membrane surrounding its natural opening, is carried through a suitable incision, to the outside of the cheek in the case of the parotid gland, or under the chin in the case of the submaxillary gland. In this new position the duct is fixed by a few stitches which are removed when the wound has healed. As a result of the operation the saliva now flows to the outside, on to the cheek or chin of the animal, instead of into the mouth, so that the measurement of the secretory activity of the gland is greatly facilitated." ('Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex'; by Ivan P. Pavlov (1927), translated by G. V. Anrep; Lecture II) A variety of techniques were then used to collect the saliva and measure either its quantity or rate of production.

Answer: To eliminate unwanted external stimuli

To be sure that he was seeing responses to only the experimental stimulus, Pavlov found he had to go to extraordinary lengths to remove extraneous stimuli, creating conditions akin to solitary confinement for the dogs. Originally, they planned to just isolate a researcher in the room with the dog, but found that the researcher provided an ongoing stream of unwanted stimuli to the dog by his very presence - breathing, blinking, moving to relieve discomfort were enough to blur the interpretation of experimental results. Next they tried placing the experimenter in an adjacent room, but there were still noises from passers-by, slamming doors, passing cars, a myriad of distracting stimuli. Finally a special three-floored laboratory was constructed with a trench around the exterior to keep outside activity at a distance. Each floor had four research rooms, all separated from each other by insulating corridors.

The middle floor of the building was empty to keep activities in one set of labs from being heard on the other floor. Each of the four research rooms was divided by sound-proof materials into two sections, one for the dog and one for the experimenter.

The experimenter did not enter the dog's room - provision of a stimulus was done using electrical or pneumatic means. As far as possible, the dog experienced only the experimental stimulus, with no other external sensory input.

Answer: Inborn reflex

As the production of saliva is in direct response to the natural stimulus for which it exists, this is an example of an inborn reflex. These are also called pure reflexes, innate responses, and unconditioned reflexes. In this case, the physical and chemical presence of food causes the dog to produce the saliva necessary to digest it.

The presence of such an inborn reflex is necessary for the investigation of how the stimuli that produce the given response can be changed, or how the response to a given stimulus can be modified.

Answer: The dog had been fed that kind of food in the past

Earlier experiments had shown that a dog taken from its mother before weaning and raised on milk did not salivate when shown solid food such as meat or bread. However, once they had been fed the food they developed a salivary response to the sight of the food. Pavlov called this, amongst other things, a signal reflex, one developed by an individual based on its life experiences. The term refers to the fact that this kind of learning seemed to occur only via a function of the cerebral hemispheres that he called signalization. This signalization process allows the development of far more complex responses than is possible from the small number of inborn reflexes possessed by any given animal. A signal reflex is more commonly called a conditioned reflex, a term which Pavlov also accepted on the grounds that the development of these reflexes depends on a number of conditions.

The aspect of Pavlov's experiments with which many are most familiar is his demonstration that it is possible to create a new signal-response link - if a dog hears some sound at the same time as it is presented with food, it will develop a salivary response to the sound by itself. We usually read of bells, but there is some dispute as to whether he actually did use them. In his 1927 lectures, he demonstrated a dog responding to a metronome exactly as it did to the sight of food. This included not only the measurable salivary production, but such motor responses as turning towards the door from which food is expected, and licking its lips. While having a nice dramatic flair, this is simply artificially creating the same learning process as occurs naturally when an animal's responses are shaped by its experiences.

Answer: The new stimulus and the natural stimulus had to be presented at the same time

Neither the natural stimulus nor the new stimulus needs to be pleasurable - avoidance behaviors are learned as readily as anticipatory ones. What Pavlov did find essential was that the two stimuli had to be presented at the same time, so that they became associated in the dog's sensory receptor system.

In fact, he went further and said that the new stimulus must be operating before the natural stimulus, with a temporal overlap during which they are both presented to the dog.

Answer: It has had its cerebrum removed or made inactive

Decerberation can involve removing of the cerebrum or cutting the spinal cord near the brain stem. The cerebrum is the large rounded part of the central nervous system which most people envisage when they use the word brain. Innate reflexes continue to operate after this process, but experiments showed that dogs who had undergone this procedure did not learn conditioned responses. (Sidenote: Experiments with cats had shown that their innate reflex to land on their feet when falling was not affected by decerberation. Lovely experiments.)

Answer: Defense reflex

The response to a painful or dangerous stimulus may involve actions which we describe as escape actions, or interpret as signs of the emotional state we call fear, but they are generically termed defense reflexes, as they contribute to safety, and the avoidance of harm. Dogs may salivate in response to a negative stimulus as well as a positive one.

In another set of experiments, Pavlov's team demonstrated that the defensive production of saliva when a dilute acid solution is placed in its mouth, along with the motor responses of shaking its head and moving its tongue to expel the liquid, can be produced by a neutral stimulus which has been presented at the same time.

Not only did they drool in eager anticipation of food, they drooled in fearful anticipation of a disgusting taste on the way. (Of course, these were not all the same dogs - quite a number of dogs were involved in the experiments, which were carried out over a period of many years.)

Answer: Loud truck bearing down on them

A truck would have been difficult to arrange in the isolated laboratory conditions under which Pavlov's experiments were conducted, but he makes reference to having successfully trained dogs to produce positive responses to all of the other stimuli. In one experiment, a dog who received a significant current to one of its limbs would respond by turning its head towards the food door, smacking its lips, and producing saliva.

While the production of saliva could be a defense reflex, the others are not.

In addition, the dog did not exhibit any of the expected defense responses, such as a change in pulse or respiration. I won't repeat Pavlov's explanation that this experiment did not really hurt the dog - you can look it up for yourself. No matter how calmly the dog eventually accepted the pain from the electric current, I personally suspect that the learning process was more than a little unpleasant.