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According to the contextual change theory of memory loss, spontaneous forgetting reflects a retrieval impairment due to subtle and unprogrammed shifts in environmental cues over a retention interval. However, Riccio, Richardson, and Ebner (1984) noted an apparent paradox in this model; specifically, laboratory studies inducing explicit shifts in contextual cues found less disruption of performance as retention intervals increased. Bouton, Nelson, and Rosas (1999) critiqued several of the claims made by Riccio et al. and concluded that the contextual cue theory is still a valid account of spontaneous forgetting. In this comment, the authors address the 3 major criticisms offered by Bouton et al., point out an inconsistency in their argument, and conclude that the original paradox still poses problems for the contextual change theory of forgetting.

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Deficits in passive avoidance learning in immature animals have been explained in terms of immature response-inhibition mechanisms, the role of age-specific defense responses to conditioned or unconditioned stimuli, or differential levels of fear acquisition. In Experiment 1, shock-elicited UCRs and fear strength were held constant by training all subjects at the same age. Sixteen-day-old rat pups received Pavlovian fear conditioning and were tested 1, 5, or 10 days later for passive avoidance of the conditioned stimuli. To offset retention losses, half of each group received a noncontingent footshock reactivation 24 h before testing. Passive avoidance latencies increased with delay (age) in reactivated groups. But with an active avoidance (escape from fear) measure (Experiment 2), performance was consistently poor and unrelated to age at testing. These data suggest that maturation of response-inhibition mechanisms may contribute to the ontogeny of passive avoidance performance. More generally, some implications of the distinction between learning and performance for developmental studies are considered. This research was supported in part by Grant MH-30223 to the third author. We thank William Jehle and David Zehr for their assistance on various aspects of the study.