These details are invented subconsciously. On top of that, people often misperceive sights and sounds in the first place. The result is that eyewitnesses almost always make mistakes. "These problems of perception and memory are part and parcel of the human condition.
「目擊者無法記清楚案發的詳細情形，往往編造一些細節去補白，這種補白是潛意識的，再加上聽覺、視覺的問題，目擊證人往往會犯一些錯誤」，李昌鈺也指出人類視覺、記憶的盲點。