Temporary connections are established when two events — one important for the organism and the other inessential — coincide in time. If a dog hears the rattle of its bowl each time before it is given food, it will very soon develop a conditioned reflex, and the rattle alone will eventually be sufficient to evoke salivation and the other reactions previously caused only by food.

Conditioned reflexes are a summary of elementary knowl­edge of the world around the animal. They reflect the basic laws governing the animal’s environment. When the feeding process is preceded by the rattle of a bowk and this happens several, times, the dog develops a conditioned reflex which means that the animal has ‘noticed’ the interconnection of the two events.

The conditioned stimulus (the rattle of the bowl) has become something like a signal for the second stimulus, and can now evoke all the responses that were formerly only induced by food.

The signalling activity (the formation of temporary con­nections) is a universal phenomenon common to all animals on our planet. Moreover, there are grounds for believing that this principle is even more universal and valid for any organism, so that even on other planets we may find animals with temporary connections. There is every reason to assume that the formation of temporary connections is one of the basic and universal laws of nature, inherent in all forms of highly organized matter. The specific properties of temporary connections can, of course, vary in each particular case.