Inhibition of saccade initiation improves saccade accuracy: The role of local and remote visual distractors in the control of saccadic eye movements.

When a distractor appears close to the target location, saccades are less accurate. However, the presence of a further distractor, remote from those stimuli, increases the saccade response latency and improves accuracy. Explanations for this are either that the second, remote distractor impacts directly on target selection processes or that the remote distractor merely impairs the ability to initiate a saccade and changes the time at which unaffected target selection processes are accessed. In order to tease these two explanations apart, here we examine the relationship between latency and accuracy of saccades to a target and close distractor pair while a remote distractor appears at variable distance. Accuracy improvements are found to follow a similar pattern, regardless of the presence of the remote distractor, which suggests that the effect of the remote distractor is not the result of a direct impact on the target selection process. Our findings support the proposal that a remote distractor impairs the ability to initiate a saccade, meaning the competition between target and close distractor is accessed at a later time, thus resulting in more accurate saccades.

How many times do I need to see to believe? The impact of intolerance of uncertainty and exposure experience on safety-learning and retention in young adults.

Individuals who score high in self-reported Intolerance of Uncertainty (IU) display difficulties updating threat associations to safe associations. Here we sought to determine whether individuals who score high in IU can learn and retain new safety associations if given more exposure. We recorded skin conductance response, pupil dilation and expectancy ratings during an associative threat learning task with acquisition, same-day extinction and next-day extinction phases. Participants (n = 144) were assigned to either a regular exposure (32 trials of same-day and next-day extinction) or extended exposure condition (48 trials of same-day and next-day extinction). We failed to replicate previous work showing that IU is associated with poorer safety-learning indexed via SCR. We found preliminary evidence for promoted safety-retention in individuals with higher Inhibitory IU in the extended exposure condition, relative to individuals with higher Inhibitory IU in the regular exposure condition, indexed via SCR. These findings further our current understanding of the role of IU in safety-learning and -retention, informing models of IU and exposure-based treatments.

Enhanced Associations With Actions of the Artist Influence Gaze Behaviour.

The aesthetic experience of the perceiver of art has been suggested to relate to the art-making process of the artist. The artist's gestures during the creation process have been stated to influence the perceiver's art-viewing experience. However, limited studies explore the art-viewing experience in relation to the creative process of the artist. We introduced eye-tracking measures to further establish how congruent actions with the artist influence perceiver's gaze behaviour. Experiments 1 and 2 showed that simultaneous congruent and incongruent actions do not influence gaze behaviour. However, brushstroke paintings were found to be more pleasing than pointillism paintings. In Experiment 3, participants were trained to associate painting actions with hand primes to enhance visuomotor and visuovisual associations with the artist's actions. A greater amount of time was spent fixating brushstroke paintings when presented with a congruent prime compared with an incongruent prime, and fewer fixations were made to these styles of paintings when presented with an incongruent prime. The results suggest that explicit links that allow perceivers to resonate with the artist's actions lead to greater exploration of preferred artwork styles.

The parallel programming of landing position in saccadic eye movement sequences.

Saccadic eye movements occur in sequences, gathering new information about the visual environment to support successful task completion. Here, we examine the control of these saccadic sequences and specifically the extent to which the spatial aspects of the saccadic responses are programmed in parallel. We asked participants to saccade to a series of visual targets and, while they shifted their gaze around the display, we displaced select targets. We found that saccade landing position was deviated toward the previous location of the target suggesting that partial parallel programming of target location information was occurring. The saccade landing position was also affected by the new target location, which demonstrates that the saccade landing position was also partially updated following the shift. This pattern was present even for targets that were the subject of the next fixation. Having a greater preview about the sequence path influenced saccade accuracy with saccades being less affected by relocations when there is less preview information. The results demonstrate that landing positions from a saccade sequence are programmed in parallel and combined with more immediate visual signals.

The role of fixation disengagement in the parallel programming of sequences of saccades.

One of the core mechanisms involved in the control of saccade responses to selected target stimuli is the disengagement from the current fixation location, so that the next saccade can be executed. To carry out everyday visual tasks, we make multiple eye movements that can be programmed in parallel. However, the role of disengagement in the parallel programming of saccades has not been examined. It is well established that the need for disengagement slows down saccadic response time. This may be important in allowing the system to program accurate eye movements and have a role to play in the control of multiple eye movements but as yet this remains untested. Here, we report two experiments that seek to examine whether fixation disengagement reduces saccade latencies when the task completion demands multiple saccade responses. A saccade contingent paradigm was employed and participants were asked to execute saccadic eye movements to a series of seven targets while manipulating when these targets were shown. This both promotes fixation disengagement and controls the extent that parallel programming can occur. We found that trial duration decreased as more targets were made available prior to fixation: this was a result both of a reduction in the number of saccades being executed and in their saccade latencies. This supports the view that even when fixation disengagement is not required, parallel programming of multiple sequential saccadic eye movements is still present. By comparison with previous published data, we demonstrate a substantial speeded of response times in these condition ("a gap effect") and that parallel programming is attenuated in these conditions.

Intolerance of uncertainty is associated with reduced attentional inhibition in the absence of direct threat.

Intolerance of uncertainty (IU) is a dispositional tendency to find uncertain situations aversive. There is limited understanding as to how IU may bias attention to uncertainty in the absence of direct threat. Here we examined the extent to which uncertain distractors and individual differences in IU impacted eye-movements during an attentional capture task. Participants were asked to move their eyes towards a target, whilst ignoring an array of distractors. An additional distractor could appear before or after the target in a near or far location from the target. We observed high IU individuals to display fewer first saccades to the target in all conditions. The results were specific to IU, over trait anxiety. Overall, these results suggest that IU modulates attention to uncertainty in the absence of direct threat. Such findings inform the conceptualisation of IU and its relation to psychopathology.

The programming of sequences of saccades.

Saccadic eye movements move the high-resolution fovea to point at regions of interest. Saccades can only be generated serially (i.e., one at a time). However, what remains unclear is the extent to which saccades are programmed in parallel (i.e., a series of such moments can be planned together) and how far ahead such planning occurs. In the current experiment, we investigate this issue with a saccade contingent preview paradigm. Participants were asked to execute saccadic eye movements in response to seven small circles presented on a screen. The extent to which participants were given prior information about target locations was varied on a trial-by-trial basis: participants were aware of the location of the next target only, the next three, five, or all seven targets. The addition of new targets to the display was made during the saccade to the next target in the sequence. The overall time taken to complete the sequence was decreased as more targets were available up to all seven targets. This was a result of a reduction in the number of saccades being executed and a reduction in their saccade latencies. Surprisingly, these results suggest that, when faced with a demand to saccade to a large number of target locations, saccade preparation about all target locations is carried out in parallel.

Empathy modulates the temporal structure of social attention.

Individuals with low empathy often show reduced attention towards social stimuli. A limitation of this literature is the lack of empirical work that has explicitly characterized how this relationship manifests itself over time. We investigate this issue by analysing data from two large eye-tracking datasets (total n = 176). Via growth-curve analysis, we demonstrate that self-reported empathy (as measured by the empathy quotient-EQ) predicts the temporal evolution of gaze behaviour under conditions where social and non-social stimuli compete for attention. In both datasets, we found that EQ not only predicted a global increase in social attention, but predicted a different temporal profile of social attention. Specifically, we detected a reliable effect of empathy on gaze towards social images after prolonged viewing. An analysis of switch latencies revealed that low-EQ observers switched gaze away from an initially fixated social image more frequently and at earlier latencies than high-EQ observers. Our analyses demonstrate that modelling these temporal components of gaze signals may reveal useful behavioural phenotypes. The explanatory power of this approach may provide enhanced biomarkers for conditions marked by deficits in empathy-related processes.

I don't know where to look: the impact of intolerance of uncertainty on saccades towards non-predictive emotional face distractors.

Attentional bias to uncertain threat is associated with anxiety disorders. Here we examine the extent to which emotional face distractors (happy, angry and neutral) and individual differences in intolerance of uncertainty (IU), impact saccades in two versions of the "follow a cross" task. In both versions of the follow the cross task, the probability of receiving an emotional face distractor was 66.7%. To increase perceived uncertainty regarding the location of the face distractors, in one of the tasks additional non-predictive cues were presented before the onset of the face distractors and target. We did not find IU to impact saccades towards non-cued face distractors. However, we found IU, over Trait Anxiety, to impact saccades towards non-predictive cueing of face distractors. Under these conditions, IU individuals' eyes were pulled towards angry face distractors and away from happy face distractors overall, and the speed of this deviation of the eyes was determined by the combination of the cue and emotion of the face. Overall, these results suggest a specific role of IU on attentional bias to threat during uncertainty. These findings highlight the potential of intolerance of uncertainty-based mechanisms to help understand anxiety disorder pathology and inform potential treatment targets.

Individual differences in responsivity to social rewards: Insights from two eye-tracking tasks.

Humans generally prefer social over nonsocial stimuli from an early age. Reduced preference for social rewards has been observed in individuals with autism spectrum conditions (ASC). This preference has typically been noted in separate tasks that measure orienting toward and engaging with social stimuli. In this experiment, we used two eye-tracking tasks to index both of these aspects of social preference in in 77 typical adults. We used two measures, global effect and preferential looking time. The global effect task measures saccadic deviation toward a social stimulus (related to 'orienting'), while the preferential looking task records gaze duration bias toward social stimuli (relating to 'engaging'). Social rewards were found to elicit greater saccadic deviation and greater gaze duration bias, suggesting that they have both greater salience and higher value compared to nonsocial rewards. Trait empathy was positively correlated with the measure of relative value of social rewards, but not with their salience. This study thus elucidates the relationship of empathy with social reward processing.

Setting things straight: A comparison of measures of saccade trajectory deviation.

In eye movements, saccade trajectory deviation has often been used as a physiological operationalization of visual attention, distraction, or the visual system's prioritization of different sources of information. However, there are many ways to measure saccade trajectories and to quantify their deviation. This may lead to noncomparable results and poses the problem of choosing a method that will maximize statistical power. Using data from existing studies and from our own experiments, we used principal components analysis to carry out a systematic quantification of the relationships among eight different measures of saccade trajectory deviation and their power to detect the effects of experimental manipulations, as measured by standardized effect size. We concluded that (1) the saccade deviation measure is a good default measure of saccade trajectory deviation, because it is somewhat correlated with all other measures and shows relatively high effect sizes for two well-known experimental effects; (2) more generally, measures made relative to the position of the saccade target are more powerful; and (3) measures of deviation based on the early part of the saccade are made more stable when they are based on data from an eyetracker with a high sampling rate. Our recommendations may be of use to future eye movement researchers seeking to optimize the designs of their studies.

What you see is what you want to see: Motivationally relevant stimuli can interrupt current resource allocation.

Arousing stimuli, either threat-related or pleasant, may be selected for priority at different stages within the processing stream. Here we examine the pattern of processing for non-task-relevant threatening (spiders: arousing to some) and pleasant stimuli (babies or chocolate: arousing to all) by recording the gaze of a spider Fearful and Non-fearful group while they performed a simple "follow the cross" task. There was no difference in first saccade latencies. Saccade trajectories showed a general hypervigilance for all stimuli in the Fearful group. Saccade landing positions corresponded to what each group would find arousing, such that the Fearful group deviated towards both types of images whereas the Non-fearful group deviated towards pleasant images. Secondary corrective saccade latencies away from threat-related stimuli were longer for the Fearful group (difficulty in disengaging) compared with the Non-fearful group. These results suggest that attentional biases towards arousing stimuli may occur at different processing stages.

Effects of Infant Cleft Lip on Adult Gaze and Perceptions of "Cuteness".

OBJECTIVE: Early mother-infant interactions are impaired in the context of infant cleft lip and are associated with adverse child psychological outcomes, but the nature of these interaction difficulties is not yet fully understood. The aim of this study was to explore adult gaze behavior and cuteness perception, which are particularly important during early social exchanges, in response to infants with cleft lip, in order to investigate potential foundations for the interaction difficulties seen in this population. METHODS: Using an eye tracker, eye movements were recorded as adult participants viewed images of infant faces with and without cleft lip. Participants also rated each infant on a scale of cuteness. RESULTS: Participants fixated significantly longer on the mouths of infants with cleft lip, which occurred at the expense of fixation on eyes. Severity of cleft lip was associated with the strength of fixation bias, with participants looking even longer at the mouths of infants with the most severe clefts. Infants with cleft lip were rated as significantly less cute than unaffected infants. Men rated infants as less cute than women overall but gave particularly low ratings to infants with cleft lip. CONCLUSIONS: Results demonstrate that the limited disturbance in infant facial configuration of cleft lip can significantly alter adult gaze patterns and cuteness perception. Our findings could have important implications for early interactions and may help in the development of interventions to foster healthy development in infants with cleft lip.

Eye spy with my little eye: Motivational relevance of visual stimuli guide eye-movements at different processing stages.

Visual stimuli may be selected for priority at different stages within the processing stream, depending on how motivationally relevant they are to the perceiver. Here we examine the extent to which individual differences in motivational relevance of task-irrelevant images (spider, crash, baby, food and neutral) guide eye-movements to a simple "follow the cross" task in 96 participants. We found affective images vs. neutral images to be generally more distracting, as shown by faster first saccade latencies and greater deviation in the final landing position from the target cross. The most arousing images (spider and food), compared to neutral images, showed the largest trajectory deviations of the first saccade. Fear of spiders specifically predicted greater deviation in the final landing position on spider images. These results suggest that attentional biases towards arousing and motivationally relevant stimuli may occur at different processing stages.

The Concurrent Programming of Saccades.

Sequences of saccades have been shown to be prepared concurrently however it remains unclear exactly what aspects of those saccades are programmed in parallel. To examine this participants were asked to make one or two target-driven saccades: a reflexive saccade; a voluntary saccade; a reflexive then a voluntary saccade; or vice versa. During the first response the position of a second target was manipulated. The new location of the second saccade target was found to impact on second saccade latencies and second saccade accuracy showing that some aspects of the second saccade program are prepared in parallel with the first. However, differences were found in the specific pattern of effects for each sequence type. These differences fit well within a general framework for saccade control in which a common priority map for saccade control is computed and the influence of saccade programs on one another depends not so much on the types of saccade being produced but rather on the rate at which their programs develop.

Dissociation between the impact of evidence on eye movement target choice and confidence judgements.

It has been suggested that the evidence used to support a decision to move our eyes and the confidence we have in that decision are derived from a common source. Alternatively, confidence may be based on further post-decisional processes. In three experiments, we examined this. In Experiment 1, participants chose between two targets on the basis of varying levels of evidence (i.e., the direction of motion coherence in a random dot kinematogram). They indicated this choice by making a saccade to one of two targets and then indicated their confidence. Saccade trajectory deviation was taken as a measure of the inhibition of the non-selected target. We found that as evidence increased so did confidence and deviations of saccade trajectory away from the non-selected target. However, a correlational analysis suggested they were not related. In Experiment 2, an option to opt-out of the choice was offered on some trials if choice proved too difficult. In this way, we isolated trials on which confidence in target selection was high (i.e., when the option to opt-out was available but not taken). Again saccade trajectory deviations were found not to differ in relation to confidence. In Experiment 3, we directly manipulated confidence, such that participants had high or low task confidence. They showed no differences in saccade trajectory deviations. These results support post-decisional accounts of confidence: evidence supporting the decision to move the eyes is reflected in saccade control, but the confidence that we have in that choice is subject to further post-decisional processes.

The time course of implicit affective picture processing: an eye movement study.

Consistent with a negativity bias account, neuroscientific and behavioral evidence demonstrates modulation of even early sensory processes by unpleasant, potentially threat-relevant information. The aim of this research is to assess the extent to which pleasant and unpleasant visual stimuli presented extrafoveally capture attention and impact eye movement control. We report an experiment examining deviations in saccade metrics in the presence of emotional image distractors that are close to a nonemotional target. We additionally manipulate the saccade latency to test when the emotional distractor has its biggest impact on oculomotor control. The results demonstrate that saccade landing position was pulled toward unpleasant distractors, and that this pull was due to the quick saccade responses. Overall, these findings support a negativity bias account of early attentional control and call for the need to consider the time course of motivated attention when affect is implicit.

The spatial impact of visual distractors on saccade latency.

Remote transient changes in the environment, such as the onset of visual distractors, impact on the execution of target directed saccadic eye movements. Studies that have examined the latency of the saccade response have shown conflicting results. When there was an element of target selection, saccade latency increased as the distance between distractor and target increased. In contrast, when target selection is minimized by restricting the target to appear on one axis position, latency has been found to be slowest when the distractor is shown at fixation and reduces as it moves away from this position, rather than from the target. Here we report four experiments examining saccade latency as target and distractor positions are varied. We find support for both a dependence of saccade latency on distractor distance from target and from fixation: saccade latency was longer when distractor is shown close to fixation and even longer still when shown in an opposite location (180°) to the target. We suggest that this is due to inhibitory interactions between the distractor, fixation and the target interfering with fixation disengagement and target selection.

Evidence that indirect inhibition of saccade initiation improves saccade acuracy.

Saccadic eye-movements to a visual target are less accurate if there are distracters close to its location (local distracters). The addition of more distracters, remote from the target location (remote distracters), invokes an involuntary increase in the response latency of the saccade and attenuates the effect of local distracters on accuracy. This may be due to the target and distracters directly competing (direct route) or to the remote distracters acting to impair the ability to disengage from fixation (indirect route). To distinguish between these, we examined the development of saccade competition by recording saccade latency and accuracy responses made to a target and local distracter compared with those made with an addition of a remote distracter. The direct route would predict that the remote distracter impacts on the developing competition between target and local distracter, while the indirect route would predict no change as the accuracy benefit here derives from accessing the same competitive process but at a later stage. We found that the presence of the remote distracter did not change the pattern of accuracy improvement. This suggests that the remote distracter was acting along an indirect route that inhibits disengagement from fixation, slows saccade initiation, and enables more accurate saccades to be made.

The spatial and temporal shape of oculomotor inhibition.

Selecting a stimulus as the target for a goal-directed movement involves inhibiting other competing possible responses. Inhibition has generally proved hard to study behaviorally, because it results in no measurable output. The effect of distractors on the shape of oculomotor and manual trajectories provide evidence of such inhibition. Individual saccades may deviate initially either towards, or away from, a competing distractor - the direction and extent of this deviation depends upon saccade latency, target predictability and the target to distractor separation. The experiment reported here used these effects to show how inhibition of distractor locations develops over time. Distractors could be presented at various distances from unpredictable and predictable targets in two separate experiments. The deviation of saccade trajectories was compared between trials with and without distractors. Inhibition was measured by saccade trajectory deviation. Inhibition was found to increase as the distractor distance from target decreased but was found to increase with saccade latency at all distractor distances (albeit to different peaks). Surprisingly, no differences were found between unpredictable and predictable targets perhaps because our saccade latencies were generally long (approximately 260-280 ms.). We conclude that oculomotor inhibition of saccades to possible target objects involves the same mechanisms for all distractor distances and target types.