Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-Ro, Daejeon 305-701, Republic of Korea.
Psychiatry Res. 2013 May 30;207(3):158-63. doi: 10.1016/j.psychres.2012.09.003. Epub 2012 Sep 25.
Randomization among successive choices is important in adaptive decision-making, particularly for strategic interactions in which the optimal strategy is a mixed strategy. Patients with schizophrenia have been reported to have deficits in random sequential behaviors arising from impaired executive function. However, whether schizophrenic patients exhibit distinct behaviors for response randomization in one- and two-person games requiring different behavioral strategies is not known. The aim of this study was to examine the response randomization of 48 schizophrenic patients and 50 healthy subjects in one- and two-person rock-paper-scissors games. Here we found that the schizophrenic patients exhibited non-random biases distinct from those of the healthy subjects (i.e., stereotypic switching in the one-person game and the tendency to choose the best response against the opponent's previous choice in the two-person game). The entropy of the choice sequences was prominently decreased in the schizophrenic patients for both games, thereby indicating an overall disturbance in the behavioral randomization in adaptive decision-making. These results suggest that the impairment of response randomization in schizophrenic patients manifests differently in interactive and non-interactive situations, which may be useful for the diagnosis and quantification of the severity of the disease.
在自适应决策中，连续选择之间的随机化很重要，特别是在最优策略是混合策略的策略互动中。据报道，精神分裂症患者的执行功能受损，导致随机顺序行为出现缺陷。然而，精神分裂症患者在需要不同行为策略的单人游戏和双人游戏中对反应随机化表现出不同的行为，这一点尚不清楚。本研究旨在研究 48 名精神分裂症患者和 50 名健康受试者在单人石头剪刀布游戏和双人石头剪刀布游戏中的反应随机化。在这里，我们发现精神分裂症患者表现出与健康受试者不同的非随机偏差（即单人游戏中的刻板转换和双人游戏中针对对手前一次选择的最佳反应的选择倾向）。对于这两种游戏，精神分裂症患者的选择序列熵明显降低，这表明他们在自适应决策中的行为随机化整体受到干扰。这些结果表明，精神分裂症患者在互动和非互动情况下反应随机化的损伤表现不同，这可能有助于疾病的诊断和严重程度的量化。
