Cressman Erin K, Franks Ian M, Enns James T, Chua Romeo
University of British Columbia, Vancouver, BC, Canada.
Conscious Cogn. 2007 Jun;16(2):265-75. doi: 10.1016/j.concog.2006.06.003. Epub 2006 Jul 18.
Shapes that are rendered invisible through backward masking are still able to influence motor responses: this is called masked priming. Yet it is unknown whether this influence is on the control of ongoing action, or whether it merely influences the initiation of an already-programmed action. We modified a masked priming procedure (Schmidt, 2002) such that the critical prime-mask sequence was displayed during the execution of an already-initiated goal-directed pointing movement. Psychophysical tests of prime visibility indicated that the identity of the prime shapes were not accessible to participants for conscious report. Yet detailed kinematic analysis of the finger in motion revealed that masked primes had an influence on the pointing trajectories within 277ms of their appearance, 56ms earlier than the trajectory deviations observed in response to the visible masks. These results indicate that subliminal shapes can indeed influence the control of ongoing motor activity.
这被称为掩蔽启动效应。然而，目前尚不清楚这种影响是作用于正在进行的动作控制，还是仅仅影响已编排动作的启动。我们修改了一种掩蔽启动程序（施密特，2002年），以便在已经启动的目标指向运动的执行过程中显示关键的启动刺激-掩蔽序列。对启动刺激可见性的心理物理学测试表明，参与者无法有意识地报告启动刺激形状的特征。然而，对运动手指的详细运动学分析显示，掩蔽启动刺激在其出现后的277毫秒内就对手指的指向轨迹产生了影响，这比在对可见掩蔽刺激的反应中观察到的轨迹偏差早56毫秒。这些结果表明，阈下形状确实能够影响正在进行的运动活动的控制。
