Effects of perceptual context on transsaccadic visual matching

Transsaccadic visual matching refers to the phenomenon in which presaccadic signals at the location of the saccade goal influence the visibility of postsaccadic test signals presented at the fovea (Jüttner & Röhler, 1993). The present study uses variations of the perceptual context, provided by the structure of the presaccadic stimulus display, to investigate the influence of spatial information, decision factors, and visual attention on this form of transsaccadic information processing. The experiments yielded the following results: First, analysis of the data in terms of signal detection theory revealed that transsaccadic visual matching manifests in a shift of decision criterion (ß) rather than in a change of sensory sensitivity (d′). The criterion shift leads to a suppression of postsaccadic stimulus information that is incompatible with presaccadic processed information. Second, the matching effect strongly depends on the structure of the presaccadic display, which suggests that mechanisms of visual attention provide the spatial binding of pre- and postsaccadic stimulus information. Third, transsaccadic matching is phenomenologically tied to the execution of the saccade and effective during a postsaccadic period extending up to 160 msec after termination of the eye movement. These findings indicate a form of context-sensitive evaluation process that could subsidize the maintenance of visual stability.     

Gradual remapping results in early retinotopic and late spatiotopic inhibition of return

Here we report that immediately following the execution of an eye movement, oculomotor inhibition of return resides in retinotopic (eye-centered) coordinates. At longer postsaccadic intervals, inhibition resides in spatiotopic (world-centered) coordinates. These results are explained in terms of perisaccadic remapping. In the interval surrounding an eye movement, information is remapped within retinotopic maps to compensate for the retinal displacement. Because remapping is not an instantaneous process, a fast, but gradual, transfer of inhibition of return from retinotopic to spatiotopic coordinates can be observed in the postsaccadic interval. The observation that visual stability is preserved in inhibition of return is consistent with its function as a "foraging facilitator," which requires locations to be inhibited across multiple eye movements. The current results support the idea that the visual system is retinotopically organized and that the appearance of a spatiotopic organization is due to remapping of visual information to compensate for eye movements.     

Decrement of the Müller-Lyer illusion with saccadic and tracking eye movements

Subjects viewed the Müller-Lyer illusion, making either saccadic or smooth tracking eye movements between the apexes of the arrow heads. The decrement in the magnitude of the illusion was significantly greater for Ss in the saccadic viewing condition. Saccadic and smooth tracking eye movements are separately controlled,and information about eye position is more readily available from the efferent signals issued to control a saccadic eye movement. The experimental findings were consistent with the hypothesis that Ss in the saccadic condition learned a new afferent efferent association. The results support a theory that visual perception is determined by efferent readiness activated by visual afferent stimulation.     

Is target movement as well as target displacement a stimulus for saccadic eye movements?

The effects of visual movement on saccadic eye movement have been examined. In a classic apparent-movement demonstration with two successively exposed line-segment targets the quality of the movement is dependent on the relative orientation of the line segments. If saccadic eye movements are elicited between the targets in this situation, the configuration leading to optimal apparent movement also leads to the shortest-latency saccades. When a single line segment is succeeded by two line segments flanking it on opposite sides, and if one of these has the same orientation as the initial one and the other a different orientation, then apparent motion is seen between the two lines with the same orientation. However, the direction of saccades elicited in this configuration is not influenced by the relative orientations of the line segments. The two results together suggest that the effect of visual movement on saccadic eye movement is nonspecific.     

Localization of targets across saccades: Role of landmark objects

Saccadic eye movements are required to bring different parts of the visual world into the foveal region of the retina. With each saccade, the images of the objects drastically change their retinal positions—nevertheless, the visual world appears continuous and does not seem to jump. How does the visual system achieve this continuous and stable percept of the visual world, despite the gross changes of its retinal projection that occur with each saccade? The present paper argues that an important factor of this type of space constancy is formed by the reafferent information, i.e., the visual display that is found when the eyes land. Three experiments demonstrate that objects present across the saccade can serve as landmarks for postsaccadic relocalization. The basic experimental manipulation consisted of a systematic displacement of these landmark objects during the saccade. The effectiveness of the landmarks was determined by analysing to what degree they modify the perceived shift of a small saccade target that was blanked for 200 ms during and after the saccade. A first experiment studied the spatial range where objects become effective as landmarks. The data show that landmarks close to the saccade target and horizontally aligned with the target are specifically effective. The second experiment demonstrates that postsaccadic localization is normally based on relational information about relative stimulus positions transferred across the saccade. A third experiment studied the effect of a prominent background frame on transsaccadic localization; the results suggest that background structures contribute only little to transsaccadic localization.     

气质与眼动控制的关系

本研究采用眼动追踪和问卷测量相结合的方法,对气质类型和眼动控制的关系进行了探讨。眼动实验为2（眼跳方向：朝向眼跳和反向眼跳）X 2（任务类型：重复眼跳和转换眼跳）组内设计;气质分数用陈会昌编制的《气质类型测试量表》测量。结果表明,气质分数与眼动特性之间存在显著的相关性,不同气质类型（神经活动类型）在抑制过程和任务重置过程中表现出不同的相互作用模式。具体而言,神经活动强度是一个基本维度,它与认知控制的抑制功能和转换功能都有着密切联系;而神经活动的灵活性和平衡性则分别是转换功能和抑制功能的重要条件。     

刺激的视觉显著性和奖赏价值对眼跳的影响

本研究旨在探索刺激的视觉显著性和奖赏价值分别在协同和竞争的条件下对眼跳过程的影响。实验材料为成对的Gabor图案,要求被试选择具有更高奖赏价值的图案,并记录下其眼动过程。实验分为协同条件和竞争条件。结果发现,在不同实验条件下,奖赏价值对眼跳命中率和潜伏期均存在显著效应;视觉显著性的效应则在不同实验条件下出现了分离。刺激驱动过程和目标驱动过程对眼动行为的影响可能是互相区别的两种不同模式。     

New equally readable charts based on anisotropy of peripheral visual acuity1

Abstract: Anstis’ equally readable chart for visual acuity has been widely quoted in textbooks on visual perception. However, this chart does not reflect the anisotropy of peripheral visual acuity that has been reported by previous studies. Here, the authors reexamined peripheral visual acuity by measuring resolution thresholds for Landolt rings and recognition thresholds for hiragana letters as a function of retinal eccentricity across two principal retinal meridians: horizontal and vertical. Observers were required to identify the orientation of a gap in the Landolt ring or recognize a hiragana letter while the stimulus was moved slowly from the periphery toward the fovea across each of four meridians: nasal, temporal, superior, and inferior. The results revealed the horizontal‐vertical anisotropy of visual acuity in accordance with the results of previous studies. The mean thresholds obtained in the vertical meridian were approximately 1.51‐fold (for Landolt rings) and 1.42‐fold (for hiragana letters) higher than those obtained in the horizontal meridian at the same retinal eccentricity. The authors propose new equally readable charts for Landolt rings and hiragana letters.     

Recognition of alphabetic characters during voluntary eye movements

In this paper we reconsider the question of vision during eye movements using a novel display procedure which guarantees that the eye was not stopped at any time during the eye movement. The results of our experiment lead us to conclude that true “saccadic suppression,” is a most elusive phenomenon. Furthermore, a brief analysis of the optics of the eye movement suggests that a substantial amount the elevation of visual threshold during eye movements can be attributed to simple retinal smear if one acknowledges the dominating importance of edge effects in visual threshold measurements.     

Feature-based attention across saccades: Pop-out in color search is spatiotopic

Our perception of the world remains stable despite the retinal shifts that occur with each saccade. The role of spatial attention in matching pre- to postsaccadic visual information has been well established, but the role of feature-based attention remains unclear. In this study, we examined the transsaccadic processing of a color pop-out target. Participants made a saccade towards a neutral target and performed a search task on a peripheral array presented once the saccade landed. A similar array was presented just before the saccade and we analyzed what aspect of this preview benefitted the postsaccadic search task. We assessed the preview effect in the spatiotopic and retinotopic reference frames, and the potential transfer of feature selectivity across the saccade. In the first experiment, the target and distractor colors remained identical for the preview and the postsaccadic array and performance improved. The largest benefit was observed at the spatiotopic location. In the second experiment, the target and distractor colors were swapped across the saccade. All responses were slowed but the cost was least at the spatiotopic location. Our results show that the preview attracted spatial attention to the target location, which was then remapped, and suggest that previewed features, specifically colors, were transferred across the saccade. Furthermore, the preview induced a spatiotopic advantage regardless of whether the target switched color or not, suggesting that spatiotopy was established independently of feature processing. Our results support independent priming effects of features versus location and underline the role of feature-based selection in visual stability.     

The role of visual attention in saccadic eye movements

The relationship between saccadic eye movements and covert orienting of visual spatial attention was investigated in two experiments. In the first experiment, subjects were required to make a saccade to a specified location while also detecting a visual target presented just prior to the eye movement. Detection accuracy was highest when the location of the target coincided with the location of the saccade, suggesting that subjects use spatial attention in the programming and/or execution of saccadic eye movements. In the second experiment, subjects were explicitly directed to attend to a particular location and to make a saccade to the same location or to a different one. Superior target detection occurred at the saccade location regardless of attention instructions. This finding shows that subjects cannot move their eyes to one location and attend to a different one. The results of these experiments suggest that visuospatial attention is an important mechanism in generating voluntary saccadic eye movements.     

Trans-saccadic perception

A basic question in cognition is how visual information obtained in separate glances can produce a stable, continuous percept. Previous explanations have included theories such as integration in a trans-saccadic buffer or storage in visual memory, or even that perception begins anew with each fixation. Converging evidence from primate neurophysiology, human psychophysics and neuroimaging indicate an additional explanation: the intention to make a saccadic eye movement leads to a fundamental alteration in visual processing itself before and after the saccadic eye movement. We outline five principles of 'trans-saccadic perception' that could help to explain how it is possible - despite discrete sensory input and limited memory - that conscious perception across saccades seems smooth and predictable.     

Eye movements and illusions of alignment

Extraction of the location of a target in the visual periphery is a fundamental visual process which may be manifested both in conscious judgments of location, such as decisions about alignment, and in the processing required to execute an eye movement to a peripheral target. In both cases, location judgement is affected by the neighbouring visual configuration. An experiment is reported in which the amplitude of saccadic eye movements has been measured to study the effect of a configuration consisting of a single 'induction line'. The results demonstrate systematic effects of this line on the size of the saccade which are closely similar to those previously found in an alignment task.     

Looking for answers: eye movements in non-visual cognitive tasks

It is not known why people move their eyes when engaged in non-visual cognition. The current study tested the hypothesis that differences in saccadic eye movement rate (EMR) during non-visual cognitive tasks reflect different requirements for searching long-term memory. Participants performed non-visual tasks requiring relatively low or high long-term memory retrieval while eye movements were recorded. In three experiments, EMR was substantially lower for low-retrieval than for high-retrieval tasks, including in an eyes closed condition in Experiment 3. Neither visual imagery nor between-task difficulty was related to EMR, although there was some evidence for a minor effect of within-task difficulty. Comparison of task-related EMRs to EMR during a no-task waiting period suggests that eye movements may be suppressed or activated depending on task requirements. We discuss a number of possible interpretations of saccadic eye movements during non-visual cognition and propose an evolutionary model that links these eye movements to memory search through an elaboration of circuitry involved in visual perception.     

Effects of antisocial personality, cocaine and opioid dependence, and gender on eye movement control

Substance-dependent patients have been reported to exhibit abnormal smooth pursuit and saccadic eye movements. However, contrasts of the effects of different substances and the effects of comorbid psychiatric symptoms such as antisocial personality have rarely been performed. Separate analyses examined the effects of cocaine dependence, opioid dependence, or antisocial personality disorder. In each analysis, sex was included as an additional grouping factor. The dependent measures were the gain of smooth pursuit eye movement and the delay and accuracy of saccadic eye movement. Analyses of covariance indicated that both cocaine dependence and antisocial personality, but not opiate dependence, were associated with a significant reduction in gain of smooth pursuit eye movement. Cocaine dependence and antisocial personality also slowed the onset of saccadic eye movements, but only in men. No group differences were found in the accuracy of saccadic eye movements. The results suggest that the neurophysiological effects of cocaine dependence and antisocial personality overshadow the effects of heroin. The significance of these findings for visual attention and reading skill has yet to be assessed.     

Information integration across saccadic eye movements

The visual world contains more information than can be perceived in a single glance. Consequently, one's perceptual representation of the environment is built up via the integration of information across saccadic eye movements. The properties of transsaccadic integration were investigated in six experiments. Subjects viewed a random-dot pattern in one fixation, then judged whether a second dot pattern viewed in a subsequent fixation was identical to or different from the first. Interpattern interval, pattern complexity, and pattern displacement were varied in order to determined the duration, capacity, and representational format of transsaccadic memory. The experimental results indicated that transsaccadic memory is an undetailed, limited-capacity, long-lasting memory that is not strictly tied to absolute spatial position. In all these respects it is similar to, and perhaps identical with, visual short-term memory. The implication of these results for theories of perceptual stability across saccades are discussed.     

Effects of informative peripheral cues on eye movements: Revisiting William James’ “derived attention”

Two experiments examined effects of peripheral information on the latency of saccadic eye movements. In Experiment 1, simple target stimuli were presented to the left or right visual field. Prior to each target, a pair of cue letters was presented for 40msec bilaterally. The relative location of the letters (W-S or S-W) was related to target location, but participants were not informed of this contingency. After a brief practice period, saccadic latencies were faster for targets at the likely location, as indicated by the letter pair. This derived peripheral cueing effect was related to participants' awareness of the relation between cue type and target location. Experiments 2A and 2B employed monocular viewing in order to compare performance across the nasal and temporal visual fields. The effect observed in Experiment 1 was confined to the nasal visual field. In a reflexive orienting condition, the effect of a unilateral letter cue was larger in the temporal visual field. It is concluded that the neurocognitive processes responsible for derived peripheral cueing are distinct from those involved in either reflexive or voluntary orienting.     

Eye-hand coordination: oculomotor control in rapid aimed limb movements

Three experiments are reported in which Ss produced rapid wrist rotations to a target while the position of their eyes was being monitored. In Experiment 1, Ss spontaneously executed a saccadic eye movement to the target around the same time as the wrist began to move. Experiment 2 revealed that wrist-rotation accuracy suffered if Ss were not allowed to move their eyes to the target, even when visual feedback about the moving wrist was unavailable. In Experiment 3, wrist rotations were equally accurate when Ss produced either a saccadic or a smooth-pursuit eye movement to the target. However, differences were observed in the initial-impulse and error-correction phases of the wrist rotations, depending on the type of eye movement involved. The results suggest that aimed limb movements use information from the oculomotor system about both the static position of the eyes and the dynamic characteristics of eye movements. Furthermore, the information that governs the initial impulse is different from that which guides final error corrections.     

Saccades predict and synchronize to visual rhythms irrespective of musical beats

ABSTRACT

Music has been shown to entrain movement. One of the body’s most frequent movements, saccades, are arguably subject to a timer that may also be susceptible to musical entrainment. We developed a continuous and highly-controlled visual search task and varied the timing of the search target presentation, it was either gaze-contingent, tap-contingent, or visually-timed. We found: (1) explicit control of saccadic timing is limited to gross duration variations and imprecisely synchronized; (2) saccadic timing does not implicitly entrain to musical beats, even when closely aligned in phase; (3) eye movements predict visual onsets produced by motor-movements (finger-taps) and externally-timed sequences, beginning fixation prior to visual onset; (4) eye movement timing can be rhythmic, synchronizing to both motor-produced and externally timed visual sequences; each unaffected by musical beats. These results provide evidence that saccadic timing is sensitive to the temporal demands of visual tasks and impervious to influence from musical beats.     

Quantifying the performance limits of human saccadic targeting during visual search.

In previous studies of saccadic targeting, the issue how visually guided saccades to unambiguous targets are programmed and executed has been examined. These studies have found different degrees of guidance for saccades depending on the task and task difficulty. In this study, we use ideal-observer analysis to estimate the visual information used for the first saccade during a search for a target disk in noise. We quantitatively compare the performance of the first saccadic decision to that of the ideal observer (ie absolute efficiency of the first saccade) and to that of the associated final perceptual decision at the end of the search (ie relative efficiency of the first saccade). Our results show, first, that at all levels of salience tested, the first saccade is based on visual information from the stimulus display, and its highest absolute efficiency is approximately 20%. Second, the efficiency of the first saccade is lower than that of the final perceptual decision after active search (with eye movements) and has a minimum relative efficiency of 19% at the lowest level of saliency investigated. Third, we found that requiring observers to maintain central fixation (no saccades allowed) decreased the absolute efficiency of their perceptual decision by up to a factor of two, but that the magnitude of this effect depended on target salience. Our results demonstrate that ideal-observer analysis can be extended to measure the visual information mediating saccadic target-selection decisions during visual search, which enables direct comparison of saccadic and perceptual efficiencies.