Lui Ming Ann, Rosenfeld J Peter, Ryan Andrew H
Northwestern University, Evanston, IL 60208, USA.
Soc Neurosci. 2009;4(6):491-509. doi: 10.1080/17470910802047964.
Previous tests of P300 in deception detection have focused mainly on amplitude analysis. Since countermeasures for such tests have been reported, we looked here at other possible variables as deception indices: P300 scalp distribution and amplitude variance, both across 30 sites. We were also concerned, for the first time, in testing for recognition of more than one guilty item in a mock crime scenario. There were three groups: (1) two-probe group, two of six items were guilty knowledge (GK) items; (2) three-probe group, three of six items were GK items; (3) control group, zero of six items were GK items. In group analyses, in the two-probe group, P300s for lies were significantly greater than P300s for truthful responses. There were significant interactions of condition (Lie vs Truth) by site, suggesting different scalp profiles for deceptive versus truthful responding. Amplitude variance across sites was also greater in Lie than in Truth blocks. These results did not obtain in the three-probe and control groups. In terms of amplitude variances in probe conditions across groups, two-probe group was larger than three-probe and control groups. Regarding individual diagnostics, the variance method yielded a greater-than-chance detection rate of 71% versus 28% false positives. Regarding amplitude at multiple nonfrontal sites, 71% of guilty subjects were detected versus 14% false positives. Grier's (1971) A' indices of various test discrimination efficiencies varied from .76 to .87. Results of the present study suggested further investigation of the variance method as a diagnostic tool for lie detection.
以往在欺骗检测中对P300的测试主要集中在幅度分析上。由于已有针对此类测试的应对措施的报道，我们在此研究了其他可能作为欺骗指标的变量：P300在头皮上的分布以及幅度方差，两者均在30个位点上进行分析。我们还首次关注在模拟犯罪场景中对多个有罪项目的识别测试。共有三组：（1）双探针组，六个项目中有两个是有罪知识（GK）项目；（2）三探针组，六个项目中有三个是GK项目；（3）对照组，六个项目中没有GK项目。在分组分析中，双探针组中，说谎时的P300显著大于真实回答时的P300。条件（说谎与真实）与位点之间存在显著交互作用，表明欺骗性回答与真实回答的头皮特征不同。说谎组中各位点的幅度方差也大于真实组。这些结果在三探针组和对照组中未出现。就各组探针条件下的幅度方差而言，双探针组大于三探针组和对照组。在个体诊断方面，方差法的检测率高于随机水平，为71%，假阳性率为28%。在多个非额叶位点的幅度方面，71%的有罪受试者被检测到，假阳性率为14%。格里尔（1971年）的各种测试辨别效率的A'指数在0.76至0.87之间。本研究结果表明，需进一步研究方差法作为一种测谎诊断工具。
