Cognitive Processing During Saccadic Eye Movements

人们进行快速的眼球运动，称为扫视，以观察他们周围的世界。两次扫视之间的静止时间称为注视。众所周知，视觉在扫视时受到抑制，因此，只有在注视时才能获得关于世界的视觉信息。最近的研究结果表明，眼跳也会干扰特定的认知过程。这项研究将确定这种现象发生的原因，同时也将探索认知眼跳抑制现象的基本特征和共性。从工作记忆、数学认知、刺激新颖性和语义记忆提取等方面进行了一系列实验，研究了四种可能的抑制机制假说。总体而言，这些实验将检查在眼睛注视期间启动的认知过程是否在眼睛移动到空间中的新位置时继续运行，或者这些过程是否在眼睛运动期间暂停。人们将被呈现一项简单的心理任务，当他们在太空中盯着一个位置时，他们将开始执行这项任务，然后在试图继续执行任务的同时，他们将以短或长的速度扫视到空间中的不同位置。如果认知处理在眼球运动过程中受到抑制，那么长眼跳(执行时间较长)对性能的影响应该比短眼跳(执行时间较短)更大。还将在另一种情况下测量表现，在这种情况下，眼睛不动。如果眼动不影响认知，在眼动状态下的表现应该等同于在无眼动状态下的表现。还将检查认知处理对扫视行为(例如，眼跳延迟、持续时间、准确性和峰值速度)的影响，以确定干扰的互易性。平均每个人每秒进行约三次眼跳(因此，每16小时工作日约有172,800次眼跳)，平均眼跳持续约30毫秒；因此，如果在眼跳期间发生抑制，这意味着认知每天被干扰约90分钟。确定这种情况发生的原因对于理解人类的认知是至关重要的，特别是对于需要许多眼动的活动，如场景感知和场景导航。这项研究对可能需要用户扫视的视觉显示器和控制面板的设计也有实际意义。

People make rapid eye movements called saccades in order to examine the world around them. The still periods between saccades are called fixations. It is well known that vision is suppressed during saccades; therefore, visual information about the world is acquired only during fixations. Recent findings have shown that saccades also interfere with particular cognitive processes. This research will determine why this occurs while also exploring the fundamental characteristics and generality of the phenomenon of cognitive saccadic suppression. Four hypotheses about the possible mechanisms underlying suppression will be investigated in a series of experiments drawn from the areas of working memory, mathematical cognition, stimulus novelty, and retrieval from semantic memory. In general, the experiments will examine whether cognitive processes that are set in motion during an eye fixation continue to operate while the eyes are moving to a new position in space or whether these processes pause during the eye movement. People will be presented with a simple mental task that they will begin to perform while they are fixating one position in space and will then make either a short or a long saccade to a different position in space while attempting to continue performing the task. If cognitive processing is suppressed during eye movements, then long saccades (which take longer to execute) should disrupt performance more than short saccades (which take less time to execute). Performance will also be measured in another condition, in which the eyes do not move. Performance in the eye-movement conditions should be equivalent to performance in the no-eye-movement condition if eye movements do not interfere with cognition. The effects of cognitive processing on saccadic behavior (e.g., saccade latency, duration, accuracy, and peak velocity) will be examined as well to determine the reciprocity of the interference.The average person makes about three saccades per second (hence, about 172,800 saccades per 16-hour working day) and the average saccade lasts about 30 ms; thus, if suppression occurs during saccades, it would mean that cognition is disrupted for approximately 90 minutes each day. Determining why this occurs is of fundamental importance to the understanding of human cognition, particularly for activities such as scene perception and scene navigation that require many eye movements. The research also has practical implications for the design of visual displays and control panels that may require users to make saccades.