Melbourne School of Psychological Sciences, University of Melbourne, 3010, Victoria, Australia.
Melbourne School of Psychological Sciences, University of Melbourne, 3010, Victoria, Australia.
Cognition. 2020 May;198:104204. doi: 10.1016/j.cognition.2020.104204. Epub 2020 Jan 31.
Brain regions involved in saccadic eye movements partially overlap with a frontoparietal network implicated in encoding numerosities. Eye movement patterns may plausibly reflect strategic scanning behaviours to resolve the open-ended task of efficiently enumerating visual arrays. If so, these patterns may help explain individual differences in enumeration acuity in terms of well-understood visual attention mechanisms. Most enumeration eye-tracking paradigms, however, do not allow for direct manipulation of eye movement behaviours to test these claims. In the current study we terminated trials after a specified number of saccades to systematically probe the time course of enumeration strategies. Fifteen adults (11 naïve, 4 informed) enumerated random dot arrays under three conditions: (1) a novel saccade-terminated design where arrays were visible until one, two or four saccades had occurred; (2) a duration-terminated design where arrays were shown for 250, 500 or 1000 ms; and (3) a response-terminated design where arrays were visible until a response. Participants gave more accurate responses when enumerating saccade-terminated trials despite taking a similar time as in the duration-terminated trials. When participants were informed how trials would terminate, their saccade onset latencies shifted to match task demands. Rotating saccade vectors to align with salient image locations accounted for variability in the orientation of saccade trajectories. These findings (1) show a combination of stimulus-derived visual processing and task-based strategic demands account for enumeration eye movements patterns, (2) validate a novel saccade-contingent trial termination procedure for studying sequences of enumeration eye movements, and (3) highlight the need to include analyses of spatial and temporal eye movement patterns into models of visual enumeration strategies.
大脑中与眼球运动相关的区域与参与数值编码的额顶网络部分重叠。眼球运动模式可能合理地反映了策略性扫描行为，以解决高效枚举视觉数组的开放式任务。如果是这样，这些模式可以根据人们对视觉注意力机制的理解，帮助解释在枚举锐度方面的个体差异。然而，大多数枚举眼动追踪范式不允许直接操纵眼球运动行为来检验这些说法。在当前研究中，我们在指定数量的眼跳后终止试验，以系统地探测枚举策略的时间进程。十五名成年人（11 名新手，4 名知情者）在三种条件下枚举随机点数组：（1）一种新的眼跳终止设计，其中数组在发生一次、两次或四次眼跳之前可见；（2）一种持续时间终止设计，其中数组显示 250、500 或 1000ms；（3）一种响应终止设计，其中数组在做出响应之前可见。尽管参与者在持续时间终止试验中花费的时间相似，但在眼跳终止试验中，他们的反应更准确。当参与者被告知试验将如何终止时，他们的眼跳起始潜伏期会转移以匹配任务要求。旋转眼跳向量以与突出的图像位置对齐可以解释眼跳轨迹方向的可变性。这些发现：（1）表明刺激衍生的视觉处理与基于任务的策略需求的组合解释了枚举眼球运动模式；（2）验证了一种新的、基于眼跳的试验终止程序，用于研究枚举眼动序列；（3）强调需要将空间和时间眼球运动模式的分析纳入视觉枚举策略模型中。
