MODIFICATION OF INSTINCTIVE BEHAVIOR 443 



its grasshopper prey by one antenna would not touch its prey if 

 both antennae were cut off, yet there are examples of instinctive 

 behaviors being modified for the benefit of the animal. Some 

 insect larvae, if they have consumed all of the plant on which they 

 usually feed, will eat other kinds of leaves and thus save their 

 lives. Fish and frogs can be taught to form new associations, for 

 after many errors they will learn to avoid obstacles placed between 

 them and their food. A dog can be taught to refrain from eating 

 a lump of sugar placed on his nose until a word is spoken, because 

 he has formed new connections which considerably change his 

 natural behavior. Such modified responses, which are caused 

 by new stimuli, are said to be conditioned. The new response 

 made by the dog is conditioned by an association formed by the 

 dog's master. 



Practical Exercise 5. Think of some of your pets, as a dog or a bird, and 

 make a list of the instinctive acts performed by this animal. Have you ever 

 tried to condition one of these instinctive responses? Why are instincts 

 important in the lives of animals ? Give some examples of household pets that 

 show how instincts may be modified. 



Self-Testing Exercise 



Instincts are usually explained as (1) (2) 



(3) . Instinctive acts are often (4) in lower 



animals. When simple (5) become (6), they are 



said to be (7). Such a reaction is usually caused by a new or 



different (8). If some animals are not able to (9) 



their (10), they die. 



PROBLEM VII. HOW ARE HABITS FORMED? 



Some of our earliest acts or behaviors are instinctive. Babies 

 do not have to be taught to suck ; but as they grow older they 

 modify this instinct. They learn to take food from a spoon and 

 to wait for it. Later on they learn, by a series of trials, to stand 

 erect and then to walk. There is a difference between the instinct 

 of sucking and the habits which are learned through repetition 

 when the child is compelled to take other food than its mother's 

 milk. A habit might be called an acquired automatic activity. 



