One of the classic studies in the field of psychology showed fake playing cards to users to see how they responded (a red 5 of spades, for example).Here is what the authors conclude.

• 在心理学领域，有一个典型的研究案例是这样的，研究者给玩牌者出示假冒的扑克牌（譬如红色的黑桃5），以观其反应。