Two component skills of object permanence were studied: existence constancy -- the infants' ability to expect that an object continues to exist after it is hidden, and localization skill -- infants' ability to search in the correct place for a hidden object. Contradictions within the literature may occur because of task lability caused by failure to: (1) study the two skills within traditional object permanence tasks, (2) examine more than one task, (3) study the two skills intra-individually, and (4) examine modality effects. These design faults were corrected in the present study. Four conditions in which the amount of information available about the object varied were designed to test Piaget's theories about object permanence and evaluate results obtained in non-traditional object permanence tasks. Eighty infants, randomly assigned to one of four groups, were tested at 4 and again at 8 months of age. Three of the groups consisted of the following experimental conditions: (1) Piaget's traditional test situation in which no sound emanated from the object; (2) sound emanating from the hidden object throughout the task; and (3) intermittent sound emanating from the object only while the object was in view. In the control condition, the object was never hidden from the infant's view. Infant behavior was scored from videotapes. Localization skill was measured by examining the order and location of infants' search. Existence constancy was measured by examining whether infants turned attention to the object after uncovering it. Data were consistent with Piagetian Theory. Existence constancy results were more similar to object permanence results than localization results. Haptic results were hierarchical (most individuals either passed or failed both skills), and infants made expected localization errors in invisible displacement trials. (Author/SS)