McMillan Neil, Roberts William A
Department of Psychology, University of Western Ontario, London, ON, Canada,
Anim Cogn. 2015 Jan;18(1):373-83. doi: 10.1007/s10071-014-0808-2. Epub 2014 Sep 17.
In a two-stimulus visual discrimination task with a reversal in reward contingencies midway through each session, pigeons produce a surprising number of both anticipatory (i.e., before the reversal) and perseverative (i.e., after the reversal) errors. In the current work, we examined pigeons' (Columba livia) patterns of responding on a 90-trial, three-stimulus visual or spatial discrimination task with two changes in reward contingency (one after Trial 30 and one after Trial 60) during each session. On probe sessions where pecking the first-correct stimulus was rewarded for the first 60 rather than 30 trials, pigeons on a spatial discrimination pecked the first-correct stimulus until it was no longer rewarded, while visual discrimination birds ceased responding to the first-correct stimulus even while it was still being rewarded. On probe sessions where the onset of the first trial was delayed 7 min, pigeons' performance on the visual discrimination was disrupted by the interval delay, but performance in the spatial condition was more similar to baseline. Pigeons use different strategies (temporal control vs. local reinforcement) on midsession reversal tasks with visual versus spatial stimuli, suggesting that they are selectively permeable to changes in information (global vs. local reinforcement rates).
在一项双刺激视觉辨别任务中，每次实验过程中奖励条件会在中途反转，鸽子会产生数量惊人的预期性（即在反转之前）和持续性（即在反转之后）错误。在当前的研究中，我们考察了鸽子（家鸽）在一项包含90次试验的三刺激视觉或空间辨别任务中的反应模式，每次实验过程中有两次奖励条件的变化（一次在第30次试验后，一次在第60次试验后）。在探测实验中，在前60次而非30次试验中啄击第一个正确刺激会得到奖励，进行空间辨别的鸽子会一直啄击第一个正确刺激，直到它不再得到奖励，而进行视觉辨别的鸽子即使在第一个正确刺激仍能得到奖励时也会停止对它做出反应。在第一次试验开始延迟7分钟的探测实验中，视觉辨别任务中鸽子的表现会因间隔延迟而受到干扰，但空间条件下的表现与基线更为相似。在涉及视觉与空间刺激的实验中途反转任务中，鸽子会采用不同的策略（时间控制与局部强化），这表明它们对信息变化（全局与局部强化率）具有选择性的通透性。
