Winkielman, P., Schwarz, N. & Belli, R. F. (1998). The role of ease of retrieval and attribution in memory judgments: Judging your memory as worse despite recalling more events. Psychological Science, 9, 124-126.

Participants who had to recall 12 childhood events (a difficult task) were more likely to infer that they can't remember large parts of their childhood than participants who had to recall 4 events (an easy task), although the former recalled three times as many events. This reflects that memory judgments are based on the experienced ease or difficulty of recall. Accordingly, the negative impact of recalling 12 events was attenuated when participants were led to attribute the experienced difficulty to the task rather than the quality of their memories. The findings emphasize the role of subjective experiences and attribution in metamemory judgments.