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Thoughts on Prof Tim Hodgson’s seminar on Development of Oculomotor Control

I was  delighted to welcome Prof Tim Hodgson from Lincoln University to Durham to give a seminar on his recent work exploring the development of oculomotor control in young children. His talk drew on a series of experiments conducted at the Lincoln Summer Scientist event where Tim and his team examined oculomotor behaviours in children as young as 3! The surprising result (to me at least!) was that very young children seemed to experience a ‘sticky fixation’, such that their gaze remained locked at fixation when a target jumped from fixation to the periphery, or when gaze cues were used to direct saccades. Gaze cues automatically activate saccade programmes in adults (e.g. Kuhn & Kingstone 2009), so the fact that these young children don’t reflexively follow gaze cues suggested to me that perhaps gaze-cueing is a learned, rather than instinctual behaviour (Cole Smith & Atkinson 2015). More provocatively, Tim also argued that even though the children’s eyes were ‘stuck’ at fixation, they were nevertheless able to covertly orient into the periphery. I harrumphed my approval at this little bit of premotor theory bashing but was mindful it was based on the observation that children were able to accurately report the appearance of a peripheral target, even though they failed to execute a saccade towards it. As Bob Kentridge suggested, perhaps there was overactive fixation which prevents the release of a saccade but not the programming of the saccade. All in all it was a fascinating and thought-provoking seminar. We then retired to the Vic for refreshments and further discussion.

Kuhn, G., & Kingstone, A. (2009). Look away! Eyes and arrows engage oculomotor responses automatically. Attention Perception & Psychophysics, 71(2), 314-327. doi:10.3758/app.71.2.314

Cole, G.G., Smith, D.T. & Atkinson, M.A. (2015). Mental state attribution and the gaze cueing effect. Attention, Perception, & Psychophysics 77(4): 1105-1115.

Dan Smith

Cortex paper now published online!

Congratulations Soazig on the publication of “Covert attention beyond the range of eye-movements: Evidence for a dissociation between exogenous and endogenous orienting” in Cortex.

“The relationship between covert shift of attention and the oculomotor system has been the subject of numerous studies. A widely held view, known as Premotor Theory, is that covert attention depends upon activation of the oculomotor system. However, recent work has argued that Premotor Theory is only true for covert, exogenous orienting of attention and that covert endogenous orienting is largely independent of the oculomotor system. To address this issue we examined how endogenous and exogenous covert orienting of attention was affected when stimuli were presented at a location outside the range of saccadic eye movements. Results from Experiment 1 showed that exogenous covert orienting was abolished when stimuli were presented beyond the range of saccadic eye movements, but preserved when stimuli were presented within this range. In contrast, in Experiment 2 endogenous covert orienting was preserved when stimuli appeared beyond the saccadic range. Finally, Experiment 3 confirmed the observations of Exp.1 and 2. Our results demonstrate that exogenous, covert orienting is limited to the range of overt saccadic eye movements, whereas covert endogenous orienting is not. These results are consistent with a weak, exogenous-only version of Premotor Theory.”

The key finding illustrated in the figure below (taken from Experiment 3), which shows that exogenous attentional capture is abolished when the cue and target lie beyond the effective oculomotor range (i.e. the cannot become the goal of a saccadic eye movement). In contrast, endogenous orienting of attention is not subject to the same restriction.