RV Atlantis 2017 Ship Data

Ocean waves cause oscillatory motion of ships. Oscillatory ship motion typically is greater in roll (i.e., the ship rolling from side to side) than in pitch (i.e., tipping from front to back). Affordances for walking on a ship at sea should be differentially influenced by ship motion in roll and pitch. When roll exceeds pitch, the maximum walkable distance within a defined path should be greater when walking along the ship’s short, or athwart axis than when walking along its long, or fore-aft axis. When pitch exceeds roll, this relation should be reversed. We asked whether such changes in ship motion would be reflected in judgments of direction-specific affordances for walking. Participants (experienced maritime crewmembers) judged how far they could walk along a narrow path on the ship deck. On different days, sailing conditions were such that the relative magnitude of pitch and roll was reversed. Judgments of direction-specific affordances for walking mirrored these changes in ship motion. The accuracy of judgments was consistent across directions, and across changes in ship motion. We conclude that experienced maritime crewmembers were sensitive to dynamic variations in affordances for walking that were, themselves, a function of dynamic properties of the animal-environment system.

海浪会引发船舶产生振荡运动。船舶的振荡运动通常在横摇（roll，即船舶左右摇摆）时的幅度大于纵摇（pitch，即船舶前后俯仰）时的幅度。海上船舶行走的可供性（affordance）会受到横摇与纵摇两种船舶运动的差异化影响。当横摇幅度大于纵摇时，沿船舶短轴（即横轴线athwart axis）行走时，预设路径内的最大可行走距离会大于沿船舶长轴（即纵轴线fore-aft axis）行走时的最大可行走距离；当纵摇幅度大于横摇时，这一关系将发生反转。本研究旨在探究船舶运动的此类变化是否会体现在行走方向特异性可供性的判断中。参与者为经验丰富的海事船员，他们需要判断自身可在船舶甲板的狭窄路径上行走的最大距离。在不同的实验航行日，纵摇与横摇的相对幅度发生了反转。针对行走方向特异性可供性的判断结果恰好反映了船舶运动的此类变化，且判断的准确性在不同行走方向以及船舶运动变化的情况下均保持一致。本研究最终得出结论：经验丰富的海事船员能够感知行走可供性的动态变化，而这类可供性本身正是动物-环境系统动态特性的函数。