Research Group of Quantitative Psychology and Individual Differences, KU Leuven, Leuven, Belgium.
Centre for Social and Cultural Psychology, KU Leuven, Leuven, Belgium.
PLoS One. 2019 May 20;14(5):e0217266. doi: 10.1371/journal.pone.0217266. eCollection 2019.
This study examines two contrasting explanations for early tendencies to fight and flee. According to a stimulus-driven explanation, goal-incompatible stimuli that are easy/difficult to control lead to the tendency to fight/flee. According to a goal-directed explanation, on the other hand, the tendency to fight/flee occurs when the expected utility of fighting/fleeing is the highest. Participants did a computer task in which they were confronted with goal-incompatible stimuli that were (a) easy to control and fighting had the highest expected utility, (b) easy to control and fleeing had the highest expected utility, and (c) difficult to control and fleeing and fighting had zero expected utility. After participants were trained to use one hand to fight and another hand to flee, they either had to choose a response or merely observe the stimuli. During the observation trials, single-pulse Transcranial Magnetic Stimulation (TMS) was applied to the primary motor cortex 450 ms post-stimulus onset and motor-evoked potentials (MEPs) were measured from the hand muscles. Results showed that participants chose to fight/flee when the expected utility of fighting/fleeing was the highest, and that they responded late when the expected utility of both responses was low. They also showed larger MEPs for the right/left hand when the expected utility of fighting/fleeing was the highest. This result can be interpreted as support for the goal-directed account, but only if it is assumed that we were unable to override the presumed natural mapping between hand (right/left) and response (fight/flight).
这项研究考察了两种截然不同的解释，用于说明早期战斗和逃跑倾向的原因。根据刺激驱动的解释，目标不一致的刺激如果容易/难以控制，就会导致战斗/逃跑的倾向。另一方面，根据目标导向的解释，当战斗/逃跑的预期效用最高时，就会出现战斗/逃跑的倾向。参与者在计算机任务中面临目标不一致的刺激，这些刺激（a）易于控制，且战斗具有最高的预期效用，（b）易于控制，且逃跑具有最高的预期效用，以及（c）难以控制，逃跑和战斗都没有预期效用。在参与者接受了用一只手战斗和另一只手逃跑的训练后，他们要么必须做出反应，要么只是观察刺激。在观察试验中，在刺激后 450 毫秒，对初级运动皮层进行单次经颅磁刺激（TMS），并从手部肌肉测量运动诱发电位（MEP）。结果表明，当战斗/逃跑的预期效用最高时，参与者选择战斗/逃跑，当两种反应的预期效用都较低时，他们的反应会延迟。当战斗/逃跑的预期效用最高时，右手/左手的 MEPs 也更大。只有假设我们无法覆盖手（右/左）和反应（战斗/逃跑）之间假定的自然映射，这一结果才能被解释为对目标导向解释的支持。
