Baracat B, Marquié J C
Centre de Recherche en Biologie du Comportement, URA 664 CNRS, Université Paul Sabatier, Toulouse, France.
Exp Aging Res. 1992 Spring-Summer;18(1-2):59-66. doi: 10.1080/03610739208253912.
Twelve young adults (age 21-25 years) and twelve older adults (age 57-65 years) performed a visual discrimination task (parallel lines) in which the following factors were manipulated: the difference in the length of the lines (3% and 9%), signal exposure duration (150, 750, and 2000 ms), and presentation modality (simultaneous and successive). The effect of repeating the task over three blocks was also controlled. Reaction time, sensitivity (d'), the decision criterion (beta), and the level of confidence the subjects had in their responses were measured and analyzed. The reaction time of the older subjects was longer than for younger ones. The difference remained constant across conditions. Signal detection analysis indicated that the ability to discriminate, as measured by d', was the same, on the whole, in the two age groups, but the sensitivity of the older was more affected by signal exposure duration than that of their younger counterparts. Contrary to what might have been expected, the older subjects used a more risky decision criterion than the younger subjects (preferring false alarms to omissions) and did not have significantly less confidence in their responses. Task repetition led to reduced reaction times and to a slightly higher level of confidence, but no age-related effects were found. The findings suggest that, in addition to a perceptual compensatory component, the longer reaction times of the older subjects include a decision-making component not necessary for their level of discrimination accuracy. The outcome of a lower criterion in the older group supports other findings according to which a more conservative decision strategy is not a general, systematic feature of the aged.
12名年轻人（年龄在21至25岁之间）和12名年长者（年龄在57至65岁之间）进行了一项视觉辨别任务（平行线辨别），其中对以下因素进行了操控：线条长度差异（3%和9%）、信号暴露持续时间（150、750和2000毫秒）以及呈现方式（同时呈现和相继呈现）。还控制了在三个组块中重复该任务的影响。测量并分析了反应时间、敏感度（d'）、决策标准（β）以及受试者对其反应的信心水平。年长者的反应时间比年轻人更长。这种差异在各种条件下保持不变。信号检测分析表明，总体而言，以d'衡量的辨别能力在两个年龄组中是相同的，但年长者的敏感度比年轻受试者更容易受到信号暴露持续时间的影响。与预期相反，年长者比年轻受试者采用了更冒险的决策标准（更倾向于误报而非漏报），并且对自己的反应并没有明显更低的信心。任务重复导致反应时间缩短以及信心水平略有提高，但未发现与年龄相关的影响。研究结果表明，除了感知补偿成分外，年长者较长的反应时间还包括一个对于他们的辨别准确性水平并非必要的决策成分。老年组较低标准的结果支持了其他研究结果，即更保守的决策策略并非老年人的普遍、系统性特征。
