Modification by Experience 267 



may have been quite new to the wasp when she dug her nest 

 there, but its recent previous experience. 



The great thing to be desired with regard to the effect of 

 individual experience upon behavior is that it shall be rapid. 

 One might at first thought say also, "that it shall be per- 

 manent." But it is probable that permanence of impression, 

 though valuable, is less so than speed of modification; for 

 too great permanence of one impression would interfere with 

 the formation of new ones. We have been often told of the 

 value that attaches to the capacity for forgetting. Judged 

 by /the standard of rapidity, the guidance of action by a 

 stimulus that has been experienced only once before, though 

 recently, is a form of modification through experience dis- 

 tinctly superior to the guidance of action by repeated stimu- 

 lation. It has been noted already that if the effect of a stimu- 

 lus is very painful, the stimulus does not need to be repeated ; 

 but obviously it is better for an animal to modify its behavior 

 rapidly without undergoing pain, which must tell upon its 

 vital energies. 



Furthermore, we may notice that while recency of experi- 

 ence is more valuable than frequency of experience as regards 

 the rapidity with which behavior is modified, nothing can 

 take the place of frequency where permanence is concerned. 

 It is not to be desired that the wasp should remain perma- 

 nently subject to the influence of these particular landmarks. 

 On the contrary, their influence must be effaced, in order that 

 she may dig and stock other nests in other localities. The 

 lasting character of the effect produced on the animals in the 

 labyrinth and box experiments has, on the other hand, been 

 proved by nearly all experimenters. One of Small's rats 

 opened a puzzle box with speed and accuracy after an inter- 

 val of forty days, during which time she had had no tests 

 whatever. The birds tested by Porter remembered the maze 



