References
- Bijou , S. W. and Sturges , P. T. 1959 . Positive reinforcers for experimental studies with children–consumables and manipulatables . Child. Deuel. , 30 : 151 – 170 .
- Ellis , N. R. and Distefano , M. K. Jr. 1959 . Effects of verbal urging and praise upon rotary pursuit performance in mentally defectives . Amer. J. Ment. Def. , 64 : 486 – 490 .
- Epstein , S. 1962 . “ The measurement of drive and conflict in humans: theory and experiment ” . In Nebraska Symposium on Motivation. , Edited by: Jones , M. R. Lincoln : Univ. Nebraska Press. .
- Gordon , S. , O'Connor , N. and Tizard , J. 1955 . Some effects of incentives on the motor performance of imbeciles on a repetitive task . Amer. J. Ment. Def. , 60 : 371 – 377 .
- Hunt , B. and Patterson , R. M. 1957 . Performance of familial mentally defective children in response to motivation on the Goodenough Draw-A-Man test . Amer. J. Ment. Def. , 62 : 326 – 329 .
- Stevenson , H. W. and Snyder , L. C. 1960 . Performance as a function of the interaction of incentive conditions . J. Personal. , 28 : 1 – 11 .
- Wolfensberger , W. 1960 . Differential rewards as motivating factors in mental deficiency research . Amer. J. Ment. Def. , 64 : 902 – 906 .
- Zigler , E. and Unell , E. 1962 . Concept-switching in normal and feebleminded children as a function of reinforcement . Amer. J. Ment. Def. , 66 : 651 – 657 .