344 



JACQUES LE MAGNEN 



In Figs. 2 to 6, it is shown that the differential appetite at the end of the 

 leaning period is evident and various with the different sensory cues offered 

 to the rat. Differential appetite is maximal with olfactory discrimination, 

 with a ratio of 3 : 1 in the intake of the two forms in the choice, compared 



A B 

 12.1 



FiG.''4. Group III : Visual discrimination. 



Gr 



12 

 9 

 6 

 3 

 

 12 

 9 

 6 

 3 

 

 12 

 9 



6 



3 

 



CHOIX 



9.1 



3,5 



r" 



4,5 



Fjg. 5. Group IV : Spatial discrimination. 



with 2 : 1 or less for the other cues (tactile and visual discrimination). 

 In the absence of any source of discrimination at the oral level in the latter 

 group, no differential appetite is learned, and in the final choice the rat does 

 not exhibit any preference. 



