SECTIONAL TRANSACTIONS.— J. 379 



learning at different times, and were subjected to different conditions of 

 incentive. 



Data were obtained relative to the effect upon rate of learning of : 



(a) a time-rate basis of payment ; 



(b) an appeal made to the workers for increased output ; 



(c) a monetary reward paid to one worker who responded to the appeal 

 by increasing output by 40 per cent. ; 



(d) the introduction of a piece-rate system of payment ; 



(e) the age and previous earnings of the workers. 

 The following conclusions are suggested : 



(a) that, as an incentive to learning the industrial process concerned, a 

 time-rate basis of payment was ineffective ; 



(b) that an appeal elicited a favourable response from one worker only ; 



(c) that anticipation of a monetary reward did not produce a favourable 

 response from all workers, nor was a favourable response always 

 immediate ; 



(d) that the introduction of a piece-rate system of payment produced 

 immediately a favourable response from most workers ; 



(e) that the effectiveness of an incentive was, to some extent, dependent 

 upon the age and social responsibilities of the workers. 



Division 2. 



Mr. R. J. Bartlett. — The difference threshold for lifted weights. 



Working with arithmetical and geometrical series of weights by methods 

 of fractionation, ranking and standard comparison, it was found that : 



(i) The nature of the field is of prime importance. Actual results 

 from small containers differ greatly from those from large con- 

 tainers weighted similarly, but obey the same laws. 



(2) Apparently, for any given set of containers uniform in size, 

 shape and appearance, there is a zone of weight to which we are 

 accustomed and adapted. In this zone Weber's law holds. 



(3) The threshold is a summation of ' constant error ' and ' scatter 

 error.' 



(4) Outside the ' Weber zone ' the ' constant error ' is the more 

 important factor. 



(5) The ' constant error ' is a regression towards a value, within the 

 ' Weber zone,' coincident with the ' expected weight ' of the 

 given container. 



(6) With practice the regression diminishes and the ' Weber zone ' 

 extends. 



(7) The law of regression, using geometric units, is of the form 

 y^cy?, where y is the regression, x the deviation of stimulus from 

 the datum value of (5), and c a constant. 



(8) This cubic law holds for published results of the lower values for 

 brightness, sound intensity, and pitch. 



(9) The ' scatter error ' about the ' best equal value ' approximates to 

 Weber's law, but would seem to decrease slowly as the stimulus 

 scale is ascended. 



Dr. J. O. Irwin. — A critical discussion of the single factor theory. 



The theory of the single General Factor (Spearman's ' g ') has been used 

 extensively in the field of mental tests. While the vanishing of the ' tetrad 



