Memory can be an accurate chronicler of past events, but is also vulnerable to loss and distortion.1 Forgetting usually occurs imperceptibly with the passing of time. Can people voluntarily forget information by wilfully suppressing it? Recent studies by Michael Anderson and Collin Green2 say "yes". These experiments have stimulated debate because the researchers suggest that their results may provide "a viable model" for Freud's much maligned theory of repression.3,4 Furthermore, the results have been linked5 to the disputed idea that people can repress and later recover memories of childhood sexual abuse.4,6
             Anderson and Green used a carefully crafted experimental design to isolate the effects of voluntary suppression on tests of memory. Participants learned a list of 40 unrelated word pairs, such as "ordeal-roach" or "moss-north". They were then prompted with the first word of 30 of the pairs. For half of the items, participants were asked to respond with the second word of the pair; for the other half, they were instructed to suppress the word from conscious awareness. Then a final memory test was carried out. The researchers asked the participants to do their best to recall the second word of each pair when presented with the first word, regardless of the earlier instructions to suppress memory for some words. Participants recalled more words from the "respond" group than words from the "suppress" group. This finding alone might simply indicate that the recall of words from the "respond" group had improved because of practice, rather than revealing an impairment of recall for words in the "suppress" group. However, ten of the word pairs that had appeared only on the study list were used as control words. Fewer suppressed words than control words were recalled. This finding cannot be attributed to the practice of recalled words, and indicates that the recall of words from the "suppress" group was indeed impaired. The same outc...