De Sá Teixeira Nuno, Hecht Heiko
Institute of Cognitive Psychology, University of Coimbra, Rua do Colégio Novo, Apartado 6153, 3001-802, Coimbra, Portugal,
Atten Percept Psychophys. 2014 May;76(4):1106-20. doi: 10.3758/s13414-014-0626-2.
The memory for the vanishing location of a horizontally moving target is usually displaced forward in the direction of motion (representational momentum) and downward in the direction of gravity (representational gravity). Moreover, this downward displacement has been shown to increase with time (representational trajectory). However, the degree to which different kinematic events change the temporal profile of these displacements remains to be determined. The present article attempts to fill this gap. In the first experiment, we replicate the finding that representational momentum for downward-moving targets is bigger than for upward motions, showing, moreover, that it increases rapidly during the first 300 ms, stabilizing afterward. This temporal profile, but not the increased error for descending targets, is shown to be disrupted when eye movements are not allowed. In the second experiment, we show that the downward drift with time emerges even for static targets. Finally, in the third experiment, we report an increased error for upward-moving targets, as compared with downward movements, when the display is compatible with a downward ego-motion by including vection cues. Thus, the errors in the direction of gravity are compatible with the perceived event and do not merely reflect a retinotopic bias. Overall, these results provide further evidence for an internal model of gravity in the visual representational system.
对水平移动目标消失位置的记忆通常会在运动方向上向前偏移（表征动量），并在重力方向上向下偏移（表征重力）。此外，这种向下的偏移已被证明会随时间增加（表征轨迹）。然而，不同运动学事件改变这些偏移时间特征的程度仍有待确定。本文试图填补这一空白。在第一个实验中，我们重复了一个发现，即向下移动目标的表征动量大于向上移动目标的表征动量，此外还表明，它在前300毫秒内迅速增加，之后趋于稳定。当不允许眼球运动时，这种时间特征会被打乱，但下降目标增加的误差不会。在第二个实验中，我们表明即使是静态目标也会出现随时间的向下漂移。最后，在第三个实验中，当通过包含运动视错觉线索使显示与向下的自我运动相匹配时，我们报告向上移动目标与向下移动目标相比误差增加。因此，重力方向上的误差与所感知的事件相符，而不仅仅反映视网膜拓扑偏差。总体而言，这些结果为视觉表征系统中重力的内部模型提供了进一步的证据。
