Naefgen Christoph, Dambacher Michael, Janczyk Markus
Department of Psychology, Eberhard Karls University of Tübingen, Schleichstraße 4, 72076, Tübingen, Germany.
University of Konstanz, Constance, Germany.
Psychol Res. 2018 Nov;82(6):1039-1052. doi: 10.1007/s00426-017-0887-1. Epub 2017 Aug 3.
Response times (RTs) for free choice tasks are usually longer than those for forced choice tasks. We examined the cause for this difference in a study with intermixed free and forced choice trials, and adopted the rationale of sequential sampling frameworks to test two alternative accounts: Longer RTs in free choices are caused (1) by lower rates of information accumulation, or (2) by additional cognitive processes that delay the start of information accumulation. In three experiments, we made these accounts empirically discriminable by manipulating decision thresholds via the frequency of catch trials (Exp. 1) or via inducing time pressure (Exp. 2 and 3). Our results supported the second account, suggesting a temporal delay of information accumulation in free choice tasks, while the accumulation rate remains comparable. We propose that response choice in both tasks relies on information accumulation towards a specific goal. While in forced choice tasks, this goal is externally determined by the stimulus, in free choice tasks, it needs to be generated internally, which requires additional time.
自由选择任务的反应时间（RTs）通常比强制选择任务的反应时间长。我们在一项混合了自由选择和强制选择试验的研究中考察了这种差异的原因，并采用顺序抽样框架的原理来检验两种不同的解释：自由选择中较长的反应时间是由（1）较低的信息积累速率导致的，或者（2）由延迟信息积累开始的额外认知过程导致的。在三个实验中，我们通过操纵捕捉试验的频率（实验1）或通过施加时间压力（实验2和3）使这些解释在经验上可区分。我们的结果支持了第二种解释，表明在自由选择任务中信息积累存在时间延迟，而积累速率保持相当。我们提出，两种任务中的反应选择都依赖于朝着特定目标的信息积累。在强制选择任务中，这个目标由外部刺激决定，而在自由选择任务中，它需要在内部生成，这需要额外的时间。
