Spatiotemporal integration of spatial frequencies

Spatial frequency processing delays suggest that their integration occurs from coarse to fine. However it may be the case that integration is flexible. The first aim of this thesis was to examine the integration of spatial frequencies and the second was to examine the delays involved in initial spatial frequency processing. A coarse to fine and a fine to coarse presentation order of filtered natural images were shown. The former is judged to be of a higher quality (experiment 1) but neither show any increase in incorrect detection reports of a fullbandwidth image (experiment 2, 3 and 4). When the first three harmonics of a square-wave were shown progressively from coarse to fine and fine to coarse the former leads to more incorrect detection reports of a square-wave (experiment 5) but the latter is favoured in judgements of square-wave resemblance (experiment 6, 8, 9a and 9b), a masking (experiment 10) and a Vernier acuity task (experiment 12). These results suggest that the integration of spatial frequencies is flexible. Despite this, the integration of spatial frequencies must occur from coarse to fine because of the delays involved in the processing of spatial frequencies. In Chapter 6 (experiments 13 - 18) it was found that two widely different spatial frequencies were judged to have simultaneous onset when they were in fact simultaneous. The results of this thesis provided evidence that the integration of spatial frequencies is flexible and dependent upon the information to be derived by any particular processing. The lack of evidence for spatial frequency processing delays suggest that a flexible integration of spatial frequencies may be possible when spatial frequencies are presented simultaneously

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 towards 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 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 implici

The relationship between aesthetic and drawing preferences

There are suggested to be similarities between what is aesthetically preferred and artistically produced; however, little research has been conducted that directly examines this relationship and its links to expertise. Here, we examined the artistic process of artists and nonartists using geometric shapes as stimuli, investigating aesthetic (how pleasing they find the shapes) and drawing preferences (which shape they would prefer to draw out of a choice of two). We examined the cognitive processes behind these preferences using eye-tracking methods both when viewing stimuli and when making drawing preferences. Drawing preference scores increased with increasing aesthetic ratings regardless of expertise. We find gaze behavior when free-viewing to reflect behavior when making a drawing preference as both artists and nonartists fixated on aesthetically preferred stimuli first, for longer and more often. Artists gaze behavior when free-viewing was also influenced by what they would prefer to draw. This suggests that artists have a more fluid relationship than nonartists between images aesthetically preferred and those preferred for drawing. Overall, we demonstrate that there is a relationship between aesthetic preference and artistic preference for production, and this varies with expertis

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

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

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

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

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