Description: Segment 1 After the first intertitle 'Prof. Pavlov, creator of the science of conditioned reflexes', film of Pavlov is shown. The first experiment is then introduced, that of determining the function of the cerebral cortex. A dog with a fistula in the salivary gland is shown, and when the dog eats, saliva drips through the fistula. Intertitles explain that the production of saliva during meals is controlled by the lower centres of the brain and that these reflexes are unconditioned. An illustration is shown of the anatomy of a dog's head and an animation shows what happens in the brain when the dog eats. Saliva is secreted not only during meals but also when sighting known, previously tasted food. This is a conditioned reflex. This is demonstrated with a live dog. An experiment is then conducted where a dog is placed in a room with a specially constructed bench. The bench reveals bowls of food and the experimenter watches from another room. Time start: 00:00:00:00 Time end: 00:05:15:07 Length: 00:05:15:07 Segment 2 In the experiment chamber, a lightbulb flashes, but the dog does not react. Then the lighting of a lamp (inadequate stimulus) is followed by the serving of food (adequate stimulus). This is demonstrated. The light flashes, the food moves into view and the dog eats the food. The combining of an inadequate stimulus with adequate stimulus results in a conditioned reflex. An animation shows the arc of a conditioned reflex passing through the cortex of the cerebral hemispheres. A newborn baby is shown refusing milk to show that newborns have no conditioned reflexes, but does have inherent reflexes such as sucking, grabbing and protective ones. Gradually though, the infant begins to develop conditioned reflexes, and a baby taking a bottle is shown. A series of animations show the development of conditioned links in the cortex of the cerebral hemispheres, adequate stimuli exciting stimulation impulses in the saliva producing centre of the brain and in the cortex of the hemispheres, inadequate stimuli producing stimulation impulses in the cortex and the superimposition of an inadequate stimulus upon an adequate one. Time start: 00:05:15:07 Time end: 00:10:51:01 Length: 00:05:35:23 Segment 3 Animations show how the numerous repetitions of the experiment result in creation of a connective link between two areas of the cortex. The same experiment is performed on a child. A boy eats and saliva drips from a tube attached to the inside of his cheek. He then develops a conditioned reflex by being strapped to a bed with a funnel above him. When a light flashes, food drops through the funnel into his mouth. A conditioned reflex is created, but when the light flashes and food does not drop down the funnel, the reflex is extinguished. A similar experiment is conducted on a monkey, with different coloured circles being lowered into its cage signalling the arrival, or non-arrival of food. Time start: 00:10:51:01 Time end: 00:16:30:10 Length: 00:05:39:08 Segment 4 Eventually, the monkey learns that the grey circle means that food has been placed in its box, and the white circle means there is no food there. However, a new stimulus is introduced, that of a bell ringing, and this inhibits the previous, conditioned reflex. This is detailed in an animation. An intertitle explains that in the process of evolution, not only have the physical aspects of animals become more complicated but also behavioral aspects. Various animals are shown in a montage. Some instincts are inborn, such as with newly hatched ducklings. They are thrown repeatedly into a pond after hatching, and swim each time to the bank. Time start: 00:16:30:10 Time end: 00:21:45:03 Length: 00:05:14:22 Segment 6 Direct stimuli of functions in animals are sex, hunger and protective instincts. A montage of various animals eating is shown, including a snake swallowing a mouse. Then reactions based on the protective instinct are shown, including a mongoose fighting a snake. Next, reactions based on the instinct of reproduction are shown, including various mating rituals. Finally, instinct of care for the offspring are shown, including a mother cat chasing a dog away from her kittens. The final intertitle reads, 'Man, by ancestry related to the lower animals, inherited the same basic instincts. But not these govern human behavior. The basis of human behavior is Reason, which is conditioned by the social environment in which man lives'. Time start: 00:27:30:00 Time end: 00:32:33:17 Length: 00:05:03:17