一个国际小组最新研究发现，人们在深思熟虑或不假思索这两种决策模式中的转换能力，取决于大脑中两个区域的神经连接强度。
研究人员在美国《国家科学院学报》上报告说，在需要作出决定时，有人可以在不假思索和深思熟虑两种决策模式中依据不同条件快速转换，而有的人却总是感到左右为难。科学家们此前并不清楚究竟是什么原因造成这种个体差异。
来自阿姆斯特丹大学的比特·福特斯曼和英国、德国及澳大利亚等国同行设计了两个试验，分别要求受试者对一些简单问题进行判断。两个试验中，前者要求力求准确率而没有时间限制，后者则要求尽快做出决定不需考虑正确率。
试验过程中对受试者大脑不同部位进行扫描结果显示，大脑皮层的某一特殊区域和大脑深处的另一特殊区域的神经连接强度，对受试者在两种决策模式中切换的能力具有决定性影响。研究人员打比方说，具有较强的连接强度好比是具有更多车道的高速公路，更容易实现超车，即思维模式的切换。
研究人员说：“这一研究结果显示，大脑内部构造的不同会对人们的决策能力造成影响。”（生物谷Bioon.com）
Nature：酵母细胞交配前的决策
Nature：鸽子协调群体行为来自“民主”决策
罗中泉博士：决策过程的神经网络模型
生物谷推荐英文摘要：
PNAS doi: 10.1073/pnas.1004932107
Cortico-striatal connections predict control over speed and accuracy in perceptual decision making
Birte U. Forstmanna,1, Alfred Anwanderb, Andreas Sch?ferb, Jane Neumannb, Scott Brownc, Eric-Jan Wagenmakersa, Rafal Bogaczd, and Robert Turnerb
aDepartment of Psychology, University of Amsterdam, 1018 TV Amsterdam, The Netherlands;
bMax Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany;
cSchool of Psychology, University of Newcastle, 2308 Newcastle, Australia; and
dDepartment of Computer Science, University of Bristol, Bristol BS8 1UB, United Kingdom
When people make decisions they often face opposing demands for response speed and response accuracy, a process likely mediated by response thresholds. According to the striatal hypothesis, people decrease response thresholds by increasing activation from cortex to striatum, releasing the brain from inhibition. According to the STN hypothesis, people decrease response thresholds by decreasing activation from cortex to subthalamic nucleus (STN); a decrease in STN activity is likewise thought to release the brain from inhibition and result in responses that are fast but error-prone. To test these hypotheses—both of which may be true—we conducted two experiments on perceptual decision making in which we used cues to vary the demands for speed vs. accuracy. In both experiments, behavioral data and mathematical model analyses confirmed that instruction from the cue selectively affected the setting of response thresholds. In the first experiment we used ultra-high-resolution 7T structural MRI to locate the STN precisely. We then used 3T structural MRI and probabilistic tractography to quantify the connectivity between the relevant brain areas. The results showed that participants who flexibly change response thresholds (as quantified by the mathematical model) have strong structural connections between presupplementary motor area and striatum. This result was confirmed in an independent second experiment. In general, these findings show that individual differences in elementary cognitive tasks are partly driven by structural differences in brain connectivity. Specifically, these findings support a cortico-striatal control account of how the brain implements adaptive switches between cautious and risky behavior.
