科学家利用点光源图形来研究人们如何判断运动的趋势。（图片提供:J. Vanrie/Brooks et al）
在漆黑的夜晚，当你快步从一条胡同中走过时，远处出现了一个黑影，其轮廓刚刚能够在暗淡的月光下看到。是否有一个陌生人在向你逼近？根据一项新的研究，如果这个人是男性，那么你的感官会得出肯定的判断，即便他实际上正越走越远。
一个人走路的姿势能够反映其当时的状态。例如，弯腰驼背以及吃力的步态象征着忧愁的情绪。研究人员通常都使用一种所谓的点光源图形——按照人体轮廓排列的光点集合——来研究这类信息。这些图形一般都只能传递最小的信息，然而只需简单地扩大代表肩部区域的点集或缩小代表腰部区域的点集，便能够使这些图形看起来更加男性化或女性化。
比利时Leuven大学的心理学家Ben Schouten和同事试图搞清，为点光源图形赋予一个特定的性别是否能够影响观察者对图形运动方向的判断。研究人员要求5名志愿者——3名女性及2名男性——在计算机屏幕上观看点光源图形的录像。通过改变光点的排列，研究人员使这些图形看起来要么很男性、要么很女性、要么很中性。志愿者每次会观看3到4秒钟的图形行走录像，然后再去判断这些图形是走向自己还是远离自己。研究人员随后向志愿者展示了第二套录像，这套录像的背景中合并了细微的变化，从而能够提供步行者行走方向的更多信息。
平均来看，在每次测试中，受试者更多地判断代表女性的图形向着远离自己的方向运动；而代表男性的图形则更多地向着自己的方向运动。研究人员在最新的《当代生物学》（Current Biology）杂志上报告了这一研究成果。而这种判断在男性和女性志愿者中并没有差别。
为什么会得出这样的结论，研究人员至今尚未搞清，但他们推测，这可能是一种进化上的优势，并打算进行更多的研究从而更好地理解这种相互关系。Schouten指出：“男性的靠近可能传递了某些危险的信号，而女性的远离则意味着可以让孩子们安全地跟随。”美国加利福尼亚州圣地亚哥市索尔克生物学研究所的神经科学家Gene R. Stoner则警告说，这里可能还有其他的可能性。（生物谷Bioon.com）
生物谷推荐原始出处：
Current Biology，Vol 18, R728-R729, 09 September 2008，Anna Brooks, Ben Schouten, Rick van der Zwan
Correlated changes in perceptions of the gender and orientation of ambiguous biological motion figures
Anna Brooks,1 Ben Schouten,2 Nikolaus F. Troje,3 Karl Verfaillie,2 Olaf Blanke,4 and Rick van der Zwan1
1 Laboratory of Perceptual Processing, Department of Psychology, Southern Cross University, Coffs Harbour, NSW 2450, Australia
2 Laboratory of Experimental Psychology, University of Leuven, Tiensestraat 102, B-3000, Leuven, Belgium
3 Department of Psychology and School of Computing, Queen's University, Kingston, Ontario, K7M 3N6, Canada
4 Laboratory of Cognitive Neuroscience, Brain-Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
The sensitivity of the mammalian visual system to biological motion cues has been shown to be general and acute [1, 2, 3]. Human observers, in particular, can deduce higher-order information, such as the orientation of a figure (which way it is facing), its gender, emotional state, and even personality traits, on the basis only of sparse motion cues. Even when the stimulus information is confined to point lights attached to the major joints of an actor (so-called point-light figures), observers can use information about the way the actor is moving to tell what they are doing, whether they are a male or female, and how they are feeling [4, 5, 6]. Here we report the novel finding that stimulus manipulations that made such walkers appear more female also had the effect of making the walkers appear more often as if they were walking away from rather than towards observers. Using frontal-view (or rear-view) point-light displays of human walkers, we asked observers to judge whether they seemed to be walking towards or away from the viewing position. Independent of their own gender, observers reliably reported those figures they perceived to be male as looking like they were approaching (as reported in [7]), but those they perceived to be female as walking away. Furthermore, figures perceived to be gender-neutral also appeared more often, although not exclusively, to be walking towards observers.
