Comalli D M, Persand D, Adolph K E
Department of Psychology, New York University, 4 Washington Place, Room 415, New York, NY, USA.
Exp Brain Res. 2017 Jun;235(6):1793-1807. doi: 10.1007/s00221-017-4879-6. Epub 2017 Mar 14.
In many situations, multiple actions are possible to achieve a goal. How do people select a particular action among equally possible alternatives? In six experiments, we determined whether action selection is consistent and biased toward one decision by observing participants' decisions to go over or under a horizontal bar set at varying heights. We assessed the height at which participants transitioned from going over to under the bar within a "gray zone"-the range of bar heights at which going over and under were both possible. In Experiment 1, participants' transition points were consistently located near the upper boundary of the gray zone, indicating a bias to go over rather than under the bar. Moreover, transitional behaviors were clustered tightly into a small region, indicating that decisions were highly consistent. Subsequent experiments examined potential influences on action selection. In Experiment 2, participants wore ankle weights to increase the cost of going over the bar. In Experiment 3, they were tested on a padded surface that made crawling under the bar more comfortable. In Experiment 4, we introduced a secondary task that required participants to crawl immediately after navigating the bar. None of these manipulations altered participants' decisions relative to Experiment 1. In Experiment 5, participants started in a crawling position, which led to significantly lower transition points. In Experiment 6, we tested 5- to 6-year-old children as in Experiment 1 to determine the effects of social pressure on action selection. Children displayed lower transition points, larger transition regions, and reduced ability to go over the bar compared to adults. Across experiments, results indicate that adults have a strong and robust bias for upright locomotion.
在许多情况下，可以通过多种行动来实现一个目标。人们如何在同样可行的选择中挑选出特定的行动呢？在六项实验中，我们通过观察参与者决定从不同高度设置的水平杆上方还是下方通过的决策，来确定行动选择是否一致以及是否偏向于某一种决策。我们评估了参与者在“灰色区域”内从越过横杆转变为从横杆下方通过时的高度——这个灰色区域是指横杆高度的范围，在这个范围内越过和从下方通过都是可行的。在实验1中，参与者的转变点始终位于灰色区域的上边界附近，这表明他们倾向于从横杆上方通过而不是下方。此外，过渡行为紧密聚集在一个小区域内，这表明决策高度一致。后续实验研究了对行动选择的潜在影响。在实验2中，参与者戴着脚踝负重以增加从横杆上方通过的成本。在实验3中，他们在一个有衬垫的表面上进行测试，这使得从横杆下方爬行更舒适。在实验4中，我们引入了一项次要任务，要求参与者在通过横杆后立即爬行。相对于实验1，这些操作都没有改变参与者的决策。在实验5中，参与者从爬行姿势开始，这导致转变点显著降低。在实验6中，我们像在实验1中那样测试了5至6岁的儿童，以确定社会压力对行动选择的影响。与成年人相比，儿童的转变点更低、转变区域更大，并且越过横杆的能力降低。在所有实验中，结果表明成年人对直立运动有强烈且稳固的偏好。
