CONDITIONED \M> UNCONDITIONED REFLEX 



association with salivary secretion, so thai ii becomes an i 



cretion if only it has been frequently presented al the time with 



the unconditioned reflex stimulus, E 1 in the moutl 



Work along lines similar to thai devised by Pavlov has more recently 

 been undertaken by students of animal behavior, who have utilized the 

 acquired habits of an animal in searching for its food in ordei 

 influence of conditioning circumstances on its procedure. I 

 iif this method depends mainly on the fad thai it can be applied to all 

 groups of animals. In carrying ou1 such an observation, ihe animal is 

 placed in one compartmenl of a <-ii '_ r <-. from which it is then r< ! t<> 



a s i H 1 compartment, the end of which is « 1 i \ i . 1 # • « l int.. two pi 



ways, one leading to food, the other leading to some apartment in 



which the animal is punished for its mistake as by receiving an electric 

 shock. Objects such as colored lights are placed in tin- different p 

 sageways, ami the animal by repeated trial comes ultimately to learn 

 which particular colored lighl -> i <_r 1 1 i I i « - ~s the passage along which he 



will receive food. A reflex has therefore becoi istablished conditioned 



<»n the particular colored light. 



On accounl of the unavailability of his publications, it is impossible 

 at presenl to -rive any complete ace. nut of Pavlov's discoveries A few- 

 facts, however, arc of such importance that it is i ry for us I 

 state them here as far as we know them. See Bayl as, /' ,"/. Two 

 mechanisms scon t . . he concerned in the conditioned refl that 

 of temporary association, ami (2) that of analysis. Temporary associa- 

 tion is well illustrated in the above experiment in which the secretion of 

 saliva is induced by a Bound Temporary association of the Bound with 

 the secretion of the saliva may readily he inhibited by all kinds of 



ternal phenomena; thus, if the dog's attention 1 omes diverted while 



tin- conditioned reflex is being stimulated, the response does not i ur. 



In a dog that had been trained 1.. Becrete saliva to the sound of a i 



ticular metronome heat, inhibition occurred one day because, .in- 1 

 t ho dot,' waa being presented with the food, the laboratory servant made 

 a m.isc outside of the building which diverted the animal's attention. 

 The conditioned reflex may also he ; red with by internal inhibi- 



tion, which is illustrated by experiments in which, after a • 



trained to respond to a given conditional r> vera! follow 



when food is not given to the animal after the particular Bensation to which 

 it has been trained to respond. The condition for examph 



its effect. 'Phis is internal inhibition, hut it is a temp 

 since the reflex returns of itself after a period of 



These experiments illustrate what is meant by • matioi tem- 



porary associations occurring in conditioned reflexes, hut in i -hat 



