In a seminal study, Shepard, Hovland, and Jenkins (1961; henceforth SHJ) assessed potential mechanisms involved in categorization learning. To do so, they sequentially trained human participants with 6 different visual categorization tasks that varied in structural complexity. Humans' exceptionally strong performance on 1 of these tasks (Type 2, organized around exclusive-or relations) could not be solely explained by structural complexity, and has since been considered the hallmark of rule-use in these tasks. In the present project, we concurrently trained pigeons on all 6 SHJ tasks. Our results revealed that the structural complexity of the tasks was highly correlated with group-level performance. Nevertheless, we observed notable individual differences in performance. Two extensions of a prominent categorization model, ALCOVE (Kruschke, 1992), suggested that disparities in the discriminability of the dimensions used to construct the experimental stimuli could account for these differences. Overall, our pigeons' generally weak performance on the Type 2 task provides no evidence of rule-use on the SHJ tasks. Pigeons thus join monkeys in the contingent of species that solve these categorization tasks solely on the basis of the physical properties of the training stimuli. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

中文翻译：

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鸽子类别学习：回顾 Shepard、Hovland 和 Jenkins (1961) 任务。

在一项开创性的研究中，Shepard、Hovland 和 Jenkins（1961 年；以下简称 SHJ）评估了分类学习中涉及的潜在机制。为此，他们依次使用 6 种不同结构复杂性不同的视觉分类任务来训练人类参与者。人类在其中一项任务（类型 2，围绕异或关系组织）上的异常出色的表现不能仅仅用结构复杂性来解释，并且自此被认为是这些任务中规则使用的标志。在本项目中，我们同时训练鸽子执行所有 6 项 SHJ 任务。我们的结果表明，任务的结构复杂性与团队层面的绩效高度相关。尽管如此，我们观察到表现上存在显着的个体差异。一个著名的分类模型 ALCOVE（Kruschke，1992）的两个扩展表明，用于构建实验刺激的维度的可区分性的差异可以解释这些差异。总体而言，我们的鸽子在 2 类任务中普遍表现不佳，没有提供 SHJ 任务中规则使用的证据。因此，鸽子与猴子一样，仅根据训练刺激的物理特性来解决这些分类任务。（PsycINFO 数据库记录 (c) 2019 APA，保留所有权利）。