填空题：根据以下材料，回答题。Psychologists take contrastive views of how exter

根据以下材料，回答题。
Psychologists take contrastive views of how external rewards, from (31)__________ praise to cold cash, affectmotivation and creativity. Behaviorists, (32)__________ research the relation (33) __________ actions and their conse-quences argue that rewards can improve performance at work and school. Cognitive researchers, who study variousaspects of mental life, maintain (34)__________ rewards often destroy creativity (35) __________ encouraging depend-ence (36)__________ approval and gifts from others.
The latter view has gained many supporters, especially (37)__________ educators, But the careful use of smallmonetary rewards sparks (38)__________in grade-school children, suggesting (39) __________properly presented in-ducements indeed aid inventiveness, (40)__________to a study in the June Journal of Personality and Social Psychol-ogy.
"If kids know they're working for a (41)__________and can focus (42)__________ a relatively challenging task,they show the most creativity", says Robert Eisenberger of the University of Delaware in Newark. "But it's easy tokill creativity by giving rewards for (43) __________performance or creating too (44)__________anticipation for re-wards."
A teacher (45) __________continually draws attention to rewards or who hands (46)__________high grades forordinary achievement ends up (47) __________discouraged students, Eisenberger holds. (48) __________an exampleof the latter point, he notes growing efforts at major universities to tighten grading standards and restore failing
(49)__________.
In earlier grades, the use of so-called token economies, in (50) __________students handle challenging problemsand receive performance-based points toward valued rewards, shows promise in raising effort and creativity, the Del-aware psychologist claims.
第(31)__________。