english: Professor Alexander explained to me, the idea of addiction we've all got in our heads, that story, comes partly from a series of experiments that were done earlier in the 20th century.
non_english: sa odvíja z časti od rady pokusov zo začiatku 20. storočia. Boli to veľmi jednoduché pokusy. Môžete si ich vyskúšať dnes večer doma, ak máte sadistickú náladu.