The first suggested answer is the method of description.
The second - so it will be: the method of comparison. At worst, microscopy.
The fourth answer is the measurement method.
Conclusion: the correct answer is No. 3.
The experiment requires intervention. In the formation of a conditioned reflex bell (conditioned stimulus) is turned on together with the appearance of the unconditioned stimulus (food for example).
А здесь ещё и объяснение на русском.
Для кого это?
Для билингвов?
Ну да. Уже об этом писали
И какие выводы?
я подумаю