Alba Rodrigo, Rodríguez William, Martínez Montserrat, Orduña Vladimir
Facultad de Psicología, Universidad Nacional Autónoma de México, México, D.F. 04510, Mexico.
Facultad de Psicología, Universidad Nacional Autónoma de México, México, D.F. 04510, Mexico.
Behav Processes. 2018 Dec;157:574-582. doi: 10.1016/j.beproc.2018.04.013. Epub 2018 Apr 22.
Previous research has shown that pigeons and other birds display a strong and consistent preference for an alternative of reinforcement that presents stimuli that allow to discriminate whether a reinforcer will be delivered or not, even when its probability of reinforcement is lower than that of another alternative without those stimuli. In contrast, most of the studies performed with rats report that they show the opposite preference, choosing the alternative with higher probability of reinforcement. To explain these opposite preferences, it has been proposed that rats and pigeons have a differential sensitivity to the conditioned inhibition that emerges from the stimulus that predicts non-reinforcement: While it does not have an impact in pigeons, it strongly influences rats´ preferences. Alternatively, it was recently proposed that there is not a fundamental difference in the behavior of rats and pigeons, but that the procedure employed to evaluate each of these species has generated the difference; in particular, it was proposed that both species prefer the discriminative alternative when the discriminative stimuli have incentive salience. Two recent studies provide support for each of these hypotheses, so that the available evidence does not allow to distinguish between them. In the present report, we present three studies that systematically explore the influence of the procedural differences between the studies with discrepant results. The obtained results provide support for the following ideas: a) there is a fundamental difference between pigeons and rats in their choice behavior in the "suboptimal choice procedure", b) considering the incentive salience of the discriminative stimuli does not resolve it, and c) rats' optimality is a consistent phenomenon, which resists manipulations in reinforcement probabilities and the absence of conditioned inhibitors in the discriminative alternative.
先前的研究表明，鸽子和其他鸟类对强化物的选择表现出强烈且一致的偏好，这种强化物呈现出的刺激能让人区分强化物是否会被给予，即便其强化概率低于另一种没有这些刺激的选择。相比之下，大多数用大鼠进行的研究报告称，它们表现出相反的偏好，选择强化概率更高的选项。为了解释这些相反的偏好，有人提出大鼠和鸽子对预测无强化的刺激所产生的条件性抑制具有不同的敏感性：虽然这对鸽子没有影响，但它强烈影响大鼠的偏好。另外，最近有人提出大鼠和鸽子的行为并没有根本差异，而是评估这两个物种所采用的程序造成了这种差异；具体而言，有人提出当辨别性刺激具有激励显著性时，这两个物种都更喜欢有辨别力的选项。最近的两项研究为这些假设中的每一个都提供了支持，所以现有证据无法区分它们。在本报告中，我们展示了三项研究，系统地探讨了结果不一致的研究之间程序差异的影响。所得结果支持以下观点：a）在“次优选择程序”中，鸽子和大鼠在选择行为上存在根本差异；b）考虑辨别性刺激的激励显著性并不能解决这一差异；c）大鼠的最优性是一种一致的现象，它不受强化概率操纵以及辨别性选项中无条件性抑制物的影响。
