Roberts W A, Coughlin R, Roberts S
Department of Psychology, University of Western Ontario, London, Ontario N6A 5C2, Canada.
Psychol Sci. 2000 May;11(3):218-22. doi: 10.1111/1467-9280.00244.
In Experiment 1, pigeons were presented with a sequence of light flashes and cued to peck a key for reward either after a fixed time or after a fixed number of flashes. Curves that showed the rate of key pecking over time within trials indicated that peak rates of response were reached near the fixed time on timing-cued trials and near the fixed number of flashes on counting-cued trials. In Experiment 2, the key cue was shifted from timing to counting or from counting to timing midway through a trial. The peak times reached after the cue change indicated that pigeons kept track of time while cued to count but did not count while cued to time. These findings suggest a basic asymmetry in the dual-mode model of timing and counting.
在实验1中，向鸽子呈现一系列闪光，并提示它们在固定时间后或固定次数的闪光后啄击一个按键以获取奖励。显示试验中按键啄击率随时间变化的曲线表明，在定时提示试验中，接近固定时间时达到反应峰值率；在计数提示试验中，接近固定闪光次数时达到反应峰值率。在实验2中，按键提示在试验中途从定时转换为计数，或从计数转换为定时。提示改变后达到的峰值时间表明，鸽子在被提示计数时能跟踪时间，但在被提示定时时不会计数。这些发现表明在计时和计数的双模式模型中存在基本的不对称性。
