8 JOSEPH U. Y ARE ROUGH 



finding in the data of the first group led him to the conclusion 

 that when the material used is such that it forms an organic unit 

 or can be attended as a unit, simultaneous presentation is prefer- 

 able; when such that this is not possible, successive presentation 

 is the better. 



Chamberlain 7 sought to ascertain the effect upon the power of 

 recall when a number of objects were displayed i) singly and 

 2) three together. For subjects he used 60 pupils each from the 

 third, fifth and eighth grades. By means of a circular disc of 

 wood certain objects were exposed in fixed order for a given 

 length of time. In the first tests these objects were exposed 

 three at a time; in the second, one at a time. The two modes of 

 display were never used with the same subject. One minute was 

 allowed for the observation of 15 objects. In the first tests 

 each object was exposed for nine seconds, while in the second 

 series three seconds were allowed each object. It is obvious, 

 then, that although one minute was given in both cases for the 

 observation of the fifteen objects, the exposure time per object 

 was unequal. The immediate recall was tested in every instance 

 by having the pupil recall at the close of the experiment all the 

 objects he could remember. These objects were listed by the 

 experimenter in the order recalled. The subjects were also pro- 

 vided with circular sheets of paper and asked to arrange the 

 objects thereon as remembered from the circular disc. The 

 author concludes that both recall and arrangement of objects are 

 stronger when the objects are seen three at a time than when 

 shown singly, a conclusion scarcely warranted by the insignificant 

 percentage of difference between the two modes of presentation. 

 The average number recalled by the three grades when the ob- 

 jects were presented singly was 9; when presented three at a time, 



9-37- 



In the human field investigations on the direction of associa- 

 tion have been made by Ebbinghaus, Muller and Schumann, 

 Miiller and Pilzecker, and Wohlgemuth. In each investigation 



7 Chamberlain, A. H., "A Memory Test with School Children," Psychol. 

 Rev., 1915, XXII, 71-76. 



