Department of Psychology, National Chung-Cheng University, Chia-Yi, 621, Taiwan.
Psychol Res. 2012 Sep;76(5):676-92. doi: 10.1007/s00426-011-0363-2. Epub 2011 Jul 15.
With p and q each standing for a familiar event, a disjunctive statement, "either p or q", seems quite different from its material conditional, "if not p then q". The notions of sufficiency and necessity seem specific to conditional statements. It is surprising, however, to find that perceived sufficiency and necessity affect disjunctive reasoning in the way they affect conditional reasoning. With B and C each standing for a category name, a universal statement, "all B are C", seems stronger than its logically equivalent conditional statement, "if B then C". However, the effects of perceived sufficiency or necessity were found to be as pronounced in conditional reasoning as in syllogistic reasoning. Furthermore, two experiments also showed that (a) MP (modus ponens)-comparable disjunctive reasoning was as difficult as MT (modus tollens)-comparable disjunctive reasoning, and that (b) MT-comparable syllogisms were easier to solve than MT problems in conditional reasoning.
当 p 和 q 分别代表一个熟悉的事件时，一个析取语句“要么 p，要么 q”，似乎与它的实质条件语句“如果不是 p，那么 q”有很大的不同。充分性和必要性的概念似乎是条件语句所特有的。然而，令人惊讶的是，人们发现感知到的充分性和必要性会以影响条件推理的方式影响析取推理。当 B 和 C 分别代表一个类别名称时，一个全称语句“所有 B 都是 C”，似乎比其逻辑等价的条件语句“如果 B，那么 C”更强。然而，在条件推理中，感知到的充分性或必要性的影响与三段论推理一样明显。此外，两项实验还表明，(a)MP（肯定前件）可比析取推理与 MT（否定后件）可比析取推理一样困难，以及 (b)MT 可比三段论比条件推理中的 MT 问题更容易解决。
