後果知識的呈現時間及延遲對後見之明偏誤之影響

Abstract

本研究嘗試由人類記憶的歷程出發探討產生後見之明偏誤的可能原因。研究中操弄後果知識呈現時間的長短（0 ms、100 ms或500 ms）及延遲回饋的時間（1題、24題或120題）以檢驗它們對回憶原始判斷的正確率、信心值及反應時間的影響，實驗材料為高、低頻的中文單字各60個。受試者先判斷該120個單字的正確部首為何並下信心值，此為原始判斷。在完成1題、24題或120題的原始判斷後，正確答案的回饋以0 ms、100 ms或500 ms的時間呈現，再請受試者回憶先前在原始判斷的部首選項及信心值。資料顯示，回憶時正確率的提高是後見之明偏誤的指標之一；當後果知識以閾下知覺的方式呈現時，回憶當初答對的高、低頻字部首時正確率會上升，相對之下，當後果知識以清楚的方式呈現時，只有回憶當初答對的低頻字部首時正確率會上升，顯示中文高、低頻字部首判斷的歷程並不完全相同。回憶時信心值的上升也是後見之明偏誤的一個指標；且只發生在原始判斷答對的項目中，後果知識以閾下知覺和清楚的方式呈現，原始信心值的回憶皆會上升。反應時間的降低則是衡量後見之明偏誤最敏感的指標；不論原始判斷答對或答錯，只要回饋時間延遲2-4分鐘以上，後果知識的呈現皆會造成人們在正確回憶時的反應時間下降。

In the present study, the delay of recall and the exposure time of the knowledge of result were manipulated to investigate the hindsight bias by a memory priming paradigm. The stimulus materials were 120 high or low frequency Chinese characters. Seventy-eight university students were randomly assigned to 3 delay-of-recall conditions (1 item, 24 items, and 120 items) to judge the correct radicals of these Chinese characters. After the original radical judgment task, participants were required to recall the radicals and the confidence ratings of the original judgment. The reaction time of the recall after the manipulation of knowledge of results (exposed for 0 ms, 100ms, or 500ms) was also recorded. Results show that the mean number of correct responses in the recall increased as a consequence of the knowledge of results. However, high or low frequency Chinese words were affected in a different way. For high frequency words, hindsight bias appeared only under 100ms exposure condition, whereas for low frequency words, hindsight bias appeared with 100ms and 500ms of exposure time. It suggests that the radical judgment processes may be different for high and low frequency Chinese characters. Hindsight bias was observed in the recall of the original confidence rating, and hindsight bias appeared under 100ms and 500ms exposure conditions. Finally, reaction time appears to be the most sensitive measure of the hindsight bias. With delay in recall (24 items or 120 items), positive priming for the recall of the original judgment was observed for items answered correctly in the original judgment as well as for items answered incorrectly. Hindsight bias thus appears to be associated with memory trace’s weakening with time in conjunction with its strengthening with the knowledge of results.