When the dog is repeatedly teased with the sight of objects inducing salivary secretion from a distance, the reaction of the salivary glands grows weaker and weaker and finally drops to zero.
Interpretation
This quote illustrates the concept of habituation, where repeated exposure to a stimulus reduces the response over time.
Ivan Pavlov's quote reflects his findings in classical conditioning and physiological responses, specifically how an organism's reaction diminishes when exposed to the same stimulus without reinforcement. In this scenario, the salivary glands of a dog eventually become less responsive to cues that previously triggered its salivation, highlighting the importance of consistency and expectation in learning and behavioral response.
In practice
In a psychology lecture about conditioning, you could use this quote to demonstrate how repeated exposures affect behavior.
If we could look through the skull into the brain of a consciously thinking person, and if the place of optimal excitability were luminous, then we should see playing over the cerebral surface, a bright spot with fantastic, waving borders constantly fluctuating in size and form, surrounded by a darkness more or less deep, covering the rest of the hemisphere.
From the described experiment it is clear that the mere act of eating, the food even not reaching the stomach, determines the stimulation of the gastric glands.
It is not accidental that all phenomena of human life are dominated by the search for daily bread - the oldest link connecting all living things, man included, with the surrounding nature.
Science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching.
Learn the ABC of science before you try to ascend to its summit.
Do not become archivists of facts. Try to penetrate to the secret of their occurrence, persistently search for the laws which govern them.
Development of Western science is based on two great achievements: the invention of the formal logical system (in Euclidean geometry) by the Greek philosophers, and the discovery of the possibility to find out causal relationships by systematic experiment (during the Renaissance). In my opinion, one has not to be astonished that the Chinese sages have not made these steps. The astonishing thing is that these discoveries were made at all.
People have always asked whether evolution is constantly driving onwards and upwards. Is there always going to be improvement? The answer is no: evolution is a progression of form and function, but it is not purposeful.
The aim of scientific thought, then, is to apply past experience to new circumstances; the instrument is an observed uniformity in the course of events. By the use of this instrument it gives us information transcending our experience, it enables us to infer things that we have not seen from things that we have seen; and the evidence for the truth of that information depends on our supposing that the uniformity holds good beyond our experience.
The world has changed far more in the past 100 years than in any other century in history. The reason is not political or economic but technological-technologies that flowed directly from advances in basic science. Clearly, no scientist better represents those advances than Albert Einstein: TIME's Person of the Century.
I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind.
Equipped with our five senses - along with telescopes and microscopes and mass spectrometers and seismographs and magnetometers and particle accelerators and detectors sensitive to the entire electromagnetic spectrum - we explore the universe around us and call the adventure science.
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