Haugan, G. M., & McIntire, R. W. (1972). Comparisons of vocal imitation, tactile stimulation, and food as reinforcers for infant vocalizations. Developmental Psychology, 6(2), 201-209.
http://dx.doi.org/10.1037/h0032089
Investigated the effects of 3 reinforcers on the vocal behavior of a total of 24 institutionalized 3-6 mo. Old infants. Results demonstrate that the rate of infant vocalizations per min. Can be increased with relatively simple types of contingent reinforcement. Adult vocal imitation was consistently the most effective in conditioning infant vocal behavior. Possible explanations for the greater effectiveness include the greater variability, more immediate reinforcement, and possible prior institutional deprivation of adult vocalization. Examination of the age and sex variables revealed no differences in the effectiveness of the reinforcers. However, both male and female 6-mo-old ss in all 3 reinforcement groups had significantly higher vocal rates during extinction than younger ss. (29 ref.) (PsycINFO Database Record (c) 2016 APA, all rights reserved)