In order to determine if infants possessed contingency awareness and if it were related to a temporal unit, two hypotheses were constructed. (1) Reinforcement of a response would probably lead to emission of that response only if the infant's next response occurred within a period of time during which he could remember the preceding response-reward contingency. (2) At birth, humans are structured for contingency awareness, yet it is undeveloped in infants because of the reduced number and frequency of responses they make which elicit rewarding stimulation from the physical environment. Of thirty-two 13- and 14-week-old infants, 16 were given audio and 16 were given visual stimulation contingent on looking at one of two circles on the ceiling of a bassinet hood during a 2-minute learning session. Of twenty-four 9- and 10-week-old infants, eight were given visual, eight were given audio, and eight were given both types of stimulation for 2 1/2 minutes. The data supported the hypotheses, and results were discussed in terms of memory and learning studies. (JS)