Keuchel I, Kohnen R, Lienert G A
Arzneimittelforschung. 1979;29(6):973-5.
Within a 2 x 2 x 2 factorial design using two treatment factors, alcohol vs. placebo and caffeine vs. placebo, with stratification for sex as a non-treatment factor in 2 x 2 x 2 groups of 7 students each, concentration test performance was measured by an arithmetic test. The interesting result was a second-order interaction between the three factors: alcohol as well as caffeine decreased concentration in males; combined treatment performance was interpreted synergistically. For females, alcohol as well as caffeine increased concentration while the combination of both had an antagonistic effect.
在一个2×2×2析因设计中，使用两个处理因素，即酒精与安慰剂、咖啡因与安慰剂，并将性别作为非处理因素进行分层，分为2×2×2组，每组7名学生，通过算术测试来测量注意力测试表现。有趣的结果是这三个因素之间存在二阶交互作用：酒精和咖啡因都会降低男性的注意力；联合处理的表现被解释为具有协同作用。对于女性来说，酒精和咖啡因都会提高注意力，而两者结合则具有拮抗作用。
