David T. Rovee

Conjugate reinforcement of infant exploratory behavior

Abstract The operant response rate of 10-week-old infants tripled within the first 6 minutes of conjugate reinforcement of foot thrusts, whereas controls receiving identical but noncontingent visual and somesthetic stimulation did not alter response rate throughout the experimental session. All infants receiving the conjugate procedure showed performance sensitive to the reinforcement contingencies for the 27-minute test period; four observations over an extended 46-minute session showed high and stable response rates prior to re-extinction after 42 minutes of continuous testing. The results are interpreted in terms of the feedback characteristics of the procedure.

Bacterial Burden and Wound Repair in Conventional and Germfree Rats

It is generally agreed that gross infection is detrimental to the wound repair processes, however, the significance of wound contamination with bacteria without the ensuing clinical signs of infection is largely unknown. It is likely that most cutaneous wounds in conventional animals are inevitably contaminated at operation or shortly thereafter. Bacterial contamination does not guarantee that infection will follow, but infection does not occur in the absence of bacteria (Casten et al, 1964).