Résumé : The authors attempted to reduplicate the Lacey phenomenon of heart rate acceleration during the performance of an interiorized mental task and its maintenance in time. For this purpose they resorted to the pavlovian conditioning paradigm. The heart-rate response was obtained repetitively thanks to a change of structure and/ or content of the task and a conditioned response was elicited in some subjects. Moreover, other types of visceral conditioning were evidenced. The authors underline the importance of such factors as anxiety, personality structure and intellectual abilities in this sort of conditioning. © 1970 S. Karger AG, Basel.