304 WALTER S. HUNTER 



mental type and the consequent bringing out of the fact that 

 this bird is not well adapted to maze work. This \\ill be noted 

 further in the fourth and fifth conclusions. 



2. It is very probable that a criterion by which to judge 

 of the complexity of a problem in relation to an animal's ability 

 to solve it is to be found in the form of the learning curve. The 

 greater this complexity, the longer will the curve fail to descend 

 permanently below a certain height which will usually be the 

 ordinate value of the graph at the first or second trial. 



3. Memory (organic) for simple labyrinth problems is prac- 

 tically perfect for four weeks, where there has been no inter- 

 vening training whatsoever. In this respect the pigeon seems 

 slightly superior to the sparrows and the cowbird tested by 

 Porter. After sixteen days, where there has been intervening 

 training «upon the same maze in various positions of rotation, the 

 pigeons used in the present experiments all made perfect records. 

 Whether this is to be interpreted as a case of organic memory 

 or as the acquisition of a new system of cues which will prevent 

 any confusion by rotation, the present experiments do not 

 determine. 



4. In learning the maze the pigeon is normally entirely de- 

 pendent upon visual and kinaesthetic cues. The relative 

 values of these vary from individual to individual. However 

 kinaesthesis does not play as important a role in the mental 

 life of the pigeon as in that of squirrels and white rats; and 

 vision is of more importance than ^^ith the latter animals. 

 Rouse" found that the pigeon can form auditory as well as visual 

 associations. Although this ^^'as not tested in the present ex- 

 periments, the fact did come out that the birds were very sen- 

 sitive to sound. 



5. The important thing that stands out as a result of the 

 present experiments upon rotation, aside from the support which 

 they give to the specific analysis of sensory control as this is 

 stated in the fourth conclusion, is that the pigeon seems capable 

 of changing its system of cues in response to the varying demands 

 of a new situation. 



" Op. cit., pp. 593-597. 



