In this paper we present an investigation into the use of visual cues during number line estimation, and their influence on cognitive processes for reducing number line estimation error. Participants completed a 0-1000 number line estimation task pre and post a brief intervention in which they observed static-visual or dynamic-visual cues (control, anchor, gaze cursor, mouse cursor) and also made estimation marks to test effective number-target estimation.  Results indicated that a significant pre-test to post-test reduction in estimation error was present for dynamic visual cues of modelled eye-gaze and mouse-cursor. However, there was no significant performance difference between pre and post-test for the control or static anchor conditions. Findings are discussed in relation to the extent to which anchor points alone are meaningful in promoting successful segmentation of the number line, and whether dynamic cues promote the utility of these locations in reducing error through attentional guidance.


Gallagher-Mitchell, T., Simms, V., & Litchfield, D. (in press). Learning from where ‘eye’ remotely look or point: impact on number line estimation error in adults. Quarterly Journal of Experimental Psychology.

Using another's gaze cue or mouse cue to improve number line estimations

This is some follow up research I did with Tom Gallagher-Mitchell and Victoria Simms as to how another's gaze cue can be used to learn from in simple visual-spatial tasks. Adults viewing where a model observer looked when completing number line tasks proceeded to learn from these training blocks and outperformed control participants in transfer blocks. Next key questions: what theory-of mind processes are involved in this gaze following task and how does this form of observational learning fair with children?


Research has shown that implicitly guiding attention via visual cues or unrelated tasks can increase the likelihood of solving insight problems. We examined whether following another person making specific skin-crossing saccades could induce similar attentional shifts and increase solution rates for Dunckers (1945) radiation problem. We presented 150 participants with one of three 30-s eye movement atterns from another problem solver: (a) focusing solely on the central tumour; (b) naturally making skin-crossing saccades between the outside area and the tumour from multiple angles; or (c) making deliberate skin-crossing saccades between the outside area and the tumour from multiple angles. Following another person making skin-crossing saccades increased the likelihood of solving the radiation problem. Our results demonstrate that another persons eye movements can promote attentional shifts that trigger insight problem solving.

Litchfield, D., & Ball, L.J. (2011). Using another's gaze as an explicit aid to insight problem solving. Quarterly Journal of Experimental Psychology, 64, 649-656.

Using another's gaze to help problem solving

This little study used one person's eye gaze as a cue for another person solving a problem. Remarkably, another's gaze could help people solve difficult insight problems, whether shown the eye movements during the 'Eureka' moment, or the eye movements of someone that knew the solution and tried to communicate it to the observer.


Introduction: Older drivers and young novice drivers have problems negotiating road junctions. Explanations for problems largely focus on limitations in visual information processing and observation errors associated with age and experience.
Method: Gaze transitions provide information on the positional relationship of fixations, providing a useful tool for highlighting gaps in driver's visual information acquisition strategies. The gaze transitions of three driver groups (young novice, young experienced, and older experienced) were compared during gap selection in right turn junction negotiation manoeuvres.
Results: When scanning the junction, young experienced drivers distributed their gaze more evenly across all areas, whereas older and novice drivers made more sweeping transitions, bypassing adjacent areas. The use of a preview strategy in the decision phase was less evident in the older experienced group compared to the younger groups.
Impact: The application of results to driver training interventions and future research are discussed.

Scott, H., Hall, L., Litchfield, D., & Westwood, D. (2013). Visual information search in simulated junction negotiation: Gaze transitions of young novice, young experienced and older experienced drivers. Journal of Safety Research, 45, 111-116.

Driver's eye movement behaviour as a function of age and experience

In this work at the University of Sunderland we tried to establish whether the increased likelihood of older drivers to have accidents was linked to their eye movement behaviour during hazardous driving situations. It turns out that whilst older drivers are still safe, they compensate for slower reflexes by waiting for larger gaps in traffic, and this is also evidenced by their active scanning strategies.


We examined how the ability to detect lung nodules in chest x-ray inspection is reflected in experience-related differences in visual search and decision making, and whether the eye-tracking metric time-to-first hit showed systematic decreases across expertise levels are examined. In the study decision making improved with expertise, however, time-to-first fixate a nodule showed only a non-significant trend to decrease with expertise. Surprisingly, naïve and expert observers allocated less visual attention at nodules compared with first and third year radiography students. This similarity in visual attention at nodules but not in decision making was explained by the fact that naïve observers were more likely to fixate and make errors on distracter regions. Time-to-first hit has been linked to expert performance in mammography, but in this study was not sufficiently sensitive to demonstrate clear linear improvements across expertise groups. This brings into question the use of this metric as an indirect measure of rapid initial holistic processing.

Donovan, T., & Litchfield, D. (2013). Looking for cancer: Expertise related differences in searching and decision making. Applied Cognitive Psychology, 27, 43-49.

Eye movements change as a function of expertise

This research reveals how with experience in a particular domain our eye movement behaviours becomes more efficient and we learn to quickly look at task-relevant areas and ignore distractors.In this case, the ability to quickly and correctly find lung cancer.


Children with epilepsy may be vulnerable to impaired social attention given the increased risk of neurobehavioural comorbidities. Social attentional orienting and the potential modulatory role of attentional control on the perceptual processing of gaze and emotion cues have not been examined in childhood onset epilepsies. Social attention mechanisms were investigated in patients with epilepsy (n = 25) aged 8–18 years old and performance compared to healthy controls (n = 30). Dynamic gaze and emotion facial stimuli were integrated into an antisaccade eye-tracking paradigm. The time to orient attention and execute a horizontal saccade toward (prosaccade) or away (antisaccade) from a peripheral target measured processing speed of social signals under conditions of low or high attentional control. Patients with epilepsy had impaired processing speed compared to healthy controls under conditions of high attentional control only when gaze and emotions were combined meaningfully to signal motivational intent of approach (happy or anger with a direct gaze) or avoidance (fear or sad with an averted gaze). Group differences were larger in older adolescent patients. Analyses of the discrete gaze emotion combinations found independent effects of epilepsy-related, cognitive and behavioural problems. A delayed disengagement from fearful gaze was also found under low attentional control that was linked to epilepsy developmental factors and was similarly observed in patients with higher reported anxiety problems. Overall, findings indicate increased perceptual processing of developmentally relevant social motivations during increased cognitive control, and the possibility of a persistent fear-related attentional bias. This was not limited to patients with chronic epilepsy, lower IQ or reported behavioural problems and has implications for social and emotional development in individuals with childhood onset epilepsies beyond remission.

Lunn, J., Donovan, T., Litchfield, D., Lewis, C., Davies, R., & Crawford, T. (2017). Social Attention in Children with Epilepsy. Brain & Cognition, 113, 76-84.

Social attention in children with epilepsy

Our social attentional orienting towards faces and where people look is a fundamental component of healthy communication. This research led by Jude Lunn investigated for the first time to what extent children with epilepsy could control their attention when responding to dynamic emotional faces. Children with epilepsy and healthy controls were asked to perform pro-saccades or antisaccades and clear impairments were found in children with epilepsy.


We conducted a series of experiments to determine whether negative priming is used in the process of target selection for a saccadic eye movement. The key questions addressed the circumstances in which the negative priming of an object takes place, and the distinction between spatial and object-based effects. Experiment 1 revealed that after fixating a target (cricket ball) amongst an array of semantically-related distracters, saccadic eye movements in a subsequent display were faster to the target than to distracters or new objects, irrespective of location. The main finding was that of the facilitation of a recent target, and not the inhibition of a recent distracter or location. Experiment 2 replicated this finding by using silhouettes of objects for selection that based on feature shape. Error rates were associated with distracters with high target-shape similarity therefore Experiment 3 presented silhouettes of animals using a distracters with low target-shape similarity. The pattern of results was similar to that of Experiment 2, with clear evidence of target facilitation rather than inhibition of distracters. Experiment 4 and 5 introduced a distractor together with the target into the probe display, to generate competitive selection in the probe condition. In these circumstances clear evidence of spatial inhibition at the location of the previous distractors emerged. We discuss the implications for our understanding of selective attention and consider why it is essential to supplement response time data with the analysis of eye movement behaviour in spatial negative priming paradigms.

Donovan, T., Crawford., T., & Litchfield, D. (2012). Negative priming for target selection with saccadic eye movements. Experimental Brain Research, 222, 483-494.

Using eye movements to reveal location-based and object-based inhibition

Over five experiments we revealed when inhbition is location-based and object based using negative priming and saccadic eye movements.


There is considerable concern that the public are not getting the message about climate change.  One possible explanation is ‘optimism bias’, where individuals overestimate the likelihood of positive events happening to them and underestimate the likelihood of negative events.  Evidence from behavioural neuroscience suggest that this bias is underpinned by selective information processing, specifically through a reduced level of neural coding of undesirable information, and an unconscious tendency for optimists to avoid fixating negative information.   Here we test how this bias in attention could relate to the processing of climate change messages.  Using eye tracking, we found that level of dispositional optimism affected visual fixations on climate change messages.  Optimists spent less time (overall dwell time) attending to any arguments about climate changes (either ‘for’ or ‘against’) with substantially shorter individual fixations on aspects of arguments for climate change, i.e. those that reflect the scientific consensus but are bad news. We also found that when asked to summarise what they had read, non-optimists were more likely to frame their recall in terms of the arguments ‘for’ climate change; optimists were significantly more likely to frame it in terms of a debate between two opposing positions.  Those highest in dispositional optimism seemeed to have the strongest and most pronounced level of optimism bias when it came to estimating the probability of being personally affected by climate change.  We discuss the importance of overcoming this cognitive bias to develop more effective strategies for communicating about climate change.

Beattie, G., Marselle, M., McGuire, L., & Litchfield, D. (in press). Staying over-optimistic about the future: Uncovering attentional biases to climate change messages. Semiotica.

Looking away from climate change

There is substantial evidence suggesting that climate change exists and is a serious global threat. To understand why this key information is being ignored by parts of society we examined how people read messages that  either support or deny climate change. We found that optimism bias was linked to how well this information was processed and intepreted, in that optimists were less likely to fully process this information and believe that they would be personally affected by climate change.


Double reading of chest x-rays is often used to ensure that fewer abnormalities are missed, but very little is known about how the search behavior of others affects observer performance. A series of experiments investigated whether radiographers benefit from knowing where another person looked for pulmonary nodules, and whether the expertise of the model providing the search behavior was a contributing factor. Experiment 1 compared the diagnostic performance of novice and experienced radiographers examining chest x-rays and found that both groups performed better when shown the search behavior of either a novice radiographer or an expert radiologist. Experiment 2 established that benefits in performance only arose when the eye movements shown were related to the search for nodules; however, only the novices diagnostic performance consistently improved when shown the experts search behavior. Experiment 3 reexamined the contribution of task, image, and the expertise of the model underlying this benefit. Consistent with Experiment 1, novice radiographers were better at identifying nodules when shown either a naives search behavior or an expert radiologists search behavior, but they demonstrated no improvement when shown a naive model not searching for nodules. Our results suggest that although the benefits of this form of attentional guidance may be short-lived, novices can scaffold their decisions based on the search behavior of others.

Litchfield, D., Ball, L. J., Donovan, T., Manning, D. J., & Crawford, T. (2010). Viewing another persons eye movements improves identification of pulmonary nodules in chest x-ray inspection. Journal of Experimental Psychology: Applied, 16, 251-262.

Using another's gaze to help complex visual search (medical image perception)

Here are a series of experiments that established how another's eye gaze could improve the search for lung cancer in medical image perception. We established that not only do novice observers benefit from viewing where an expert looked when searching for lung cancer, but also that novices show the same benefit when they viewed another unskilled observer perform the same task!


Rapid scene recognition is a global visual process we can all exploit to guide search. This ability is thought to underpin expertise in medical image perception yet there is no direct evidence that isolates the expertise-specific contribution of processing scene previews on subsequent eye movement performance. We used the flash-preview moving window paradigm (Castelhano & Henderson, 2007) to investigate this issue. Expert radiologists and novice observers underwent 2 experiments whereby participants viewed a 250ms scene preview or a mask before searching for a target. Observers looked for everyday objects from real-world scenes (Experiment 1), and searched for lung nodules from medical images (Experiment 2). Both expertise groups exploited the brief preview of the upcoming scene to more efficiently guide windowed search in Experiment 1, but there was only a weak effect of domain-specific expertise in Experiment 2, with experts showing small improvements in search metrics with scene previews. Expert diagnostic performance was better than novices in all conditions but was not contingent on seeing the scene preview, and scene preview actually impaired novice diagnostic performance. Experiment 3 required novice and experienced observers to search for a variety of abnormalities from different medical images. Rather than maximising the expertise-specific advantage of processing scene previews, both novices and experienced radiographers were worse at detecting abnormalities with scene previews. We discuss how restricting access to the initial glimpse can be compensated for by subsequent search and discovery processing, but there can still be costs in integrating a fleeting glimpse of a medical scene.


Litchfield D., & Donovan, T. (2016). Worth a quick look? Initial scene previews can guide eye movements as a function of domain-specific expertise but can also have unforeseen costs. Journal of Experimental Psychology: Human Perception and Performance, 42, 984-994.

Getting the gist of medical images using the
'Flash-Preview Moving Window' paradigm

This is work I did with Tim Donovan to establish for the first time whether an expert is better than a novice at exploiting the initial glimpse of familiar scenes to guide their eye movements and decisions. We found some very unexpected findings here... that observers actually performed worse when given brief glimpses of the upcoming medical scenes!