We recently found that initial-link stimuli signaling trial outcomes (signals) in a concurrent-chains procedure exerted imperfect control during initial and terminal links. Here, we conducted a follow-up experiment to investigate further such imperfect control. Five pigeons worked on a concurrent-chains procedure in which one alternative led to a terminal link ending in a smaller-sooner reinforcer delivery, and the other in a larger-later reinforcer. During initial links of some trials, compound stimuli (signals) signaled the trial outcome. We assessed control by signal dimensions in Conflicting trials, in which the dimensions signaled conflicting outcomes. Unlike our previous experiment, signals remained present during terminal links. During initial links, preference favored the signaled key in Signaled trials, and the key signaled by the dimension exerting stronger control in Conflicting trials, suggesting strong signal control. Initial-link choice also depended on trial outcomes; preference was overall biased towards the smaller-sooner key. Terminal-link responding was primarily controlled by the key peck producing terminal-link entry, although some weak signal control was also evident. Thus, signal control during initial and terminal links was enhanced, and control by key-peck location during terminal links persisted, when signals remained present during terminal links. This suggests that our previous findings were partly related to temporal separation between signals and trial outcomes, and to history effects producing strong control by key-peck location.

我们最近发现初始链接刺激信号试验结果（信号) 在并发链过程中，在初始和终端链接期间施加了不完美的控制。在这里，我们进行了后续实验，以进一步研究这种不完善的控制。五只鸽子在并行链程序中工作，其中一种选择导致末端链接以较小的较早强化物递送结束，而另一种则以较大的较晚强化物结束。在一些试验的初始环节，复合刺激（信号）表明试验结果。我们在冲突试验中通过信号维度评估控制，其中维度表示冲突的结果。与我们之前的实验不同，信号在终端链接期间仍然存在。在初始链接中，偏好偏好信号试验中的信号键，而在冲突试验中由维度施加更强控制信号的键，暗示强信号控制。初始链接的选择还取决于试验结果；偏好总体上偏向于较小的较早的键。终端链接响应主要由产生终端链接入口的键啄控制，尽管一些微弱的信号控制也很明显。因此，增强了初始和终端链路期间的信号控制，并且在终端链路期间通过键啄定位的控制持续存在，当信号在终端链路期间保持存在时。这表明我们之前的研究结果部分与信号和试验结果之间的时间分离有关，并且与通过键啄位置产生强大控制的历史效应有关。终端链接响应主要由产生终端链接入口的键啄控制，尽管一些微弱的信号控制也很明显。因此，增强了初始和终端链路期间的信号控制，并且在终端链路期间通过键啄定位的控制持续存在，当信号在终端链路期间保持存在时。这表明我们之前的研究结果部分与信号和试验结果之间的时间分离有关，并且与通过键啄位置产生强大控制的历史效应有关。终端链接响应主要由产生终端链接入口的键啄控制，尽管一些微弱的信号控制也很明显。因此，增强了初始和终端链路期间的信号控制，并且在终端链路期间通过键啄定位的控制持续存在，当信号在终端链路期间保持存在时。这表明我们之前的研究结果部分与信号和试验结果之间的时间分离有关，并且与通过键啄位置产生强大控制的历史效应有关。