Linde L
National Defence Research Establishment, Dept. 5, Stockholm, Sweden.
Ergonomics. 1995 May;38(5):864-85. doi: 10.1080/00140139508925157.
In experiment 1 eight male and eight female subjects were randomly assigned to either a caffeine or a placebo condition. Caffeine (150 mg) was given at midnight and at 4 a.m. Oral temperature, subjective ratings of fatigue and mood, and performance in two cognitive tasks (an auditive attention task and a visual coding task) were assessed. Subjective 'drowsiness' and 'tiredness' increased significantly more in subjects given placebo than in subjects given caffeine treatment. The effects of drug treatment in performance and temperature were non-significant. However, the temperature of female subjects increased between midnight and 4 a.m. and the temperature of male subjects decreased during the same period of time. On the other hand, at 5 a.m. female subjects rated themselves as more sleepy, tired and 'disorganized' than the male subjects. In experiment 2 nine female and nine male subjects were assigned randomly to either placebo or caffeine treatment. Caffeine (200 mg) was given at 5 a.m. Oral temperature, subjective ratings of fatigue and mood, and level of performance in three cognitive tasks (the same as above plus Raven's progressive matrices) were assessed. Moreover, the subjects rated the effort of performing each task. The effects of drug treatment in level of performance were non-significant. However, the subjective effort of performing the auditive attention task increased significantly in subjects given placebo treatment, suggesting a compensatory arousal mechanism (Broadbent 1971). The effect of gender on temperature was non-significant. There was a significant interaction between gender and treatment in respect of subjective effort of performing the matrices task. In men caffeine decreased subjective effort and in women subjective effort was increased by caffeine. Experiment 3 was set up to investigate the hypothesis that negative effects of caffeine in women, observed in experiment 2, were due to over-optimal ('vigilance-related') arousal for the visual coding and matrices tasks. Ten female and eight male non-sleep deprived subjects were given 200 mg caffeine or placebos at 3 p.m. and tested at 4 p.m. Experiment 3 was not found to support the over-optimal 'vigilance-related-arousal' hypothesis. Effects of caffeine in performance and effort were non-significant in experiment 3. Combining data from experiments 2 and 3 gave a significant three-way interaction between caffeine, time for experiment and rule complexity in the visual coding task. When there was a complex rule, caffeine was found to have a positive effect in experiment 3 and a negative effect in experiment 2.
在实验1中，8名男性和8名女性受试者被随机分配到咖啡因组或安慰剂组。午夜和凌晨4点给予咖啡因（150毫克）。评估口腔温度、疲劳和情绪的主观评分，以及两项认知任务（听觉注意力任务和视觉编码任务）中的表现。服用安慰剂的受试者主观上的“嗜睡”和“疲倦”程度比接受咖啡因治疗的受试者显著增加更多。药物治疗对表现和体温的影响不显著。然而，女性受试者的体温在午夜至凌晨4点之间升高，而男性受试者的体温在同一时间段内下降。另一方面，凌晨5点时，女性受试者自我感觉比男性受试者更困倦、疲倦和“无条理”。在实验2中，9名男性和9名女性受试者被随机分配到安慰剂组或咖啡因治疗组。凌晨5点给予咖啡因（200毫克）。评估口腔温度、疲劳和情绪的主观评分，以及三项认知任务（与上述相同，加上瑞文渐进矩阵测验）中的表现水平。此外，受试者对执行每项任务的努力程度进行评分。药物治疗对表现水平的影响不显著。然而，接受安慰剂治疗的受试者在执行听觉注意力任务时的主观努力程度显著增加，这表明存在一种补偿性唤醒机制（布罗德本特，1971年）。性别对体温的影响不显著。在执行矩阵任务的主观努力方面，性别与治疗之间存在显著的交互作用。对男性而言，咖啡因降低了主观努力程度，而对女性而言，咖啡因增加了主观努力程度。实验3的设立是为了研究这样一个假设，即实验2中观察到的咖啡因对女性的负面影响是由于视觉编码和矩阵任务的过度最佳（“与警觉相关”）唤醒所致。10名未被剥夺睡眠的女性和8名男性受试者在下午3点服用200毫克咖啡因或安慰剂，并在下午4点进行测试。实验3并未支持过度最佳的“与警觉相关的唤醒”假设。在实验3中，咖啡因对表现和努力程度的影响不显著。将实验2和实验3的数据合并后，在视觉编码任务中，咖啡因、实验时间和规则复杂性之间存在显著的三因素交互作用。当存在复杂规则时，发现在实验3中咖啡因有积极作用，而在实验2中有消极作用。
