Motion onset does not capture attention when subsequent motion is “smooth”

Moving Stimulus Perimetry: A New Functional Test for Glaucoma

Purpose

Static pointwise perimetric sensitivities of less than approximately 19 dB are unreliable in glaucoma owing to excessive variability. We propose using moving stimuli to increase detectability, decrease variability, and hence increase this dynamic range.

Methods

A moving stimulus was designed to travel parallel to the average nerve fiber bundle orientation at each location, and compared against an otherwise identical static stimulus. To assess dynamic range, psychometric functions were measured at 4 locations of each of 10 subjects. To assess clinically realistic test-retest variability, 34 locations of 94 subjects with glaucoma and glaucoma suspects were tested twice, 6 months apart. Pointwise sensitivity estimates were compared using generalized estimating equation regression models. The test-retest limits of agreement for each stimulus were assessed, adjusted for within-eye clustering.

Results

Using static stimuli, 9 of the 40 psychometric functions had less than a 90% maximum response probability, suggesting being beyond the dynamic range. Eight of those locations had asymptotic maximum of more than 90% with moving stimuli. Sensitivities were higher for moving stimuli (P < 0.001); the difference increased as sensitivity decreased (P < 0.001). Test-retest limits of agreement were narrower for moving stimuli (-6.35 to +6.48 dB) than static stimuli (-12.7 to +7.81 dB). Sixty-two percent of subjects preferred using moving stimuli versus 19% who preferred static stimuli.

Conclusions

Using a moving stimulus increases perimetric sensitivities in regions of glaucomatous loss. This extends the effective dynamic range, allowing reliable testing later into the disease. Results are more repeatable, and the test is preferred by most subjects.

Translational Relevance

Moving stimuli allow reliable testing in patients with more severe glaucoma than currently possible.

Translating experimental paradigms into individual-differences research: Contributions, challenges, and practical recommendations

Psychological science has long been cleaved by a fundamental divide between researchers who experimentally manipulate variables and those who measure existing individual-differences. Increasingly, however, researchers are appreciating the value of integrating these approaches. Here, we used visual attention research as a case-in-point for how this gap can be bridged. Traditionally, researchers have predominately adopted experimental approaches to investigating visual attention. Increasingly, however, researchers are integrating individual-differences approaches with experimental approaches to answer novel and innovative research questions. However, individual differences research challenges some of the core assumptions and practices of experimental research. The purpose of this review, therefore, is to provide a timely summary and discussion of the key issues. While these are contextualised in the field of visual attention, the discussion of these issues has implications for psychological research more broadly. In doing so, we provide eight practical recommendations for proposed solutions and novel avenues for research moving forward.

Motion onset really does capture attention

Several properties of visual stimuli have been shown to capture attention, one of which is the onset of motion. However, whether motion onset truly captures attention has been debated. It has been argued that motion onset only captured attention in previous studies because properties of the animated motion used in those experiments caused it to be "jerky" (i.e., there were gaps between successive images during animated motion). The present study sought to determine whether natural motion onset captures attention. Additionally, the present study further examined the circumstances under which animated motion onset, the only type of motion onset that can be produced on a computer display, does and does not capture attention. In Experiment 1, participants identified target letters in search arrays containing distinct animated motion types, either accompanied or unaccompanied by a new object. Animated motion onset captured attention, but not when the motion onset was accompanied by a new object, indicating that prior failures to replicate capture by animated motion onset were limited because a new object had always been included in the display. Experiment 2 employed natural motion rather than animated motion and found that participants were fastest at identifying motion-onset targets compared to other target types. These results provide further support for the claim that motion onset captures attention.

The role of unique color changes and singletons in attention capture

Previous studies have shown that a sudden color change is typically less salient in capturing attention than the onset of a new object. Von Mühlenen, Rempel, and Enns (Psychological Science 16: 979-986, 2005) showed that a color change can capture attention as effectively as the onset of a new object given that it occurs during a period of temporal calm, where no other display changes happen. The current study presents a series of experiments that further investigate the conditions under which a change in color captures attention, by disentangling the change signal from the onset of a singleton. The results show that the item changing color receives attentional priority irrespective of whether this change goes along with the appearance of a singleton or not.

Fixation not required: characterizing oculomotor attention capture for looming stimuli

A stimulus moving toward us, such as a ball being thrown in our direction or a vehicle braking suddenly in front of ours, often represents a stimulus that requires a rapid response. Using a visual search task in which target and distractor items were systematically associated with a looming object, we explored whether this sort of looming motion captures attention, the nature of such capture using eye movement measures (overt/covert), and the extent to which such capture effects are more closely tied to motion onset or the motion itself. We replicated previous findings indicating that looming motion induces response time benefits and costs during visual search Lin, Franconeri, & Enns(Psychological Science 19(7): 686-693, 2008). These differences in response times were independent of fixation, indicating that these capture effects did not necessitate overt attentional shifts to a looming object for search benefits or costs to occur. Interestingly, we found no differences in capture benefits and costs associated with differences in looming motion type. Combined, our results suggest that capture effects associated with looming motion are more likely subserved by covert attentional mechanisms rather than overt mechanisms, and attention capture for looming motion is likely related to motion itself rather than the onset of motion.

Early, but not late visual distractors affect movement synchronization to a temporal-spatial visual cue

The ease of synchronizing movements to a rhythmic cue is dependent on the modality of the cue presentation: timing accuracy is much higher when synchronizing with discrete auditory rhythms than an equivalent visual stimulus presented through flashes. However, timing accuracy is improved if the visual cue presents spatial as well as temporal information (e.g., a dot following an oscillatory trajectory). Similarly, when synchronizing with an auditory target metronome in the presence of a second visual distracting metronome, the distraction is stronger when the visual cue contains spatial-temporal information rather than temporal only. The present study investigates individuals' ability to synchronize movements to a temporal-spatial visual cue in the presence of same-modality temporal-spatial distractors. Moreover, we investigated how increasing the number of distractor stimuli impacted on maintaining synchrony with the target cue. Participants made oscillatory vertical arm movements in time with a vertically oscillating white target dot centered on a large projection screen. The target dot was surrounded by 2, 8, or 14 distractor dots, which had an identical trajectory to the target but at a phase lead or lag of 0, 100, or 200 ms. We found participants' timing performance was only affected in the phase-lead conditions and when there were large numbers of distractors present (8 and 14). This asymmetry suggests participants still rely on salient events in the stimulus trajectory to synchronize movements. Subsequently, distractions occurring in the window of attention surrounding those events have the maximum impact on timing performance.

The role of flicker and abrupt displacement in attention capture by motion onsets

Sunny and von Mühlenen (Psychonomic Bulletin & Review, 18, 1050-1056, 2011) showed that an onset of motion captured attention only when the motion was jerky (refreshed at 8 or 17 Hz), but not when it was smooth (33 or 100 Hz). However, it remained unclear why the onset of jerky motion captures attention. In the present study, we systematically tested the role of different aspects of jerky motion in capturing attention. Simple flicker without motion did not capture attention in the same way as jerky motion (Exp. 1). An abrupt displacement between 0.26° and 1.05° captured attention, irrespective of whether the stimulus subsequently continued to move smoothly (Exp. 2) or whether it remained stationary (Exps. 3 and 4). A displaced stimulus that was preceded briefly at the new location by a figure-8 placeholder did not capture attention (Exp. 5). These results are explained within a masking account, according to which abrupt onsets and abrupt displacements receive a processing advantage because they escape forward masking by the preceding figure-8 placeholders.