Author: Timothy Hodgson

Eyelander at CVRS London 2023

Timothy Hodgson Conferences, Eyelander, Impact

Last week I attended the 18th Biennial Child Vision Research Society meeting at UCL Great Ormond Street Institute of Child Health. The meeting included a symposium in honour of the late Oliver Braddick, co-founder of the UCL/Oxford Visual Development Unit together with Janette Atkinson who gave an impressive overview of the unit’s pioneering work on infant vision over the decades as part of the session.

Amongst the many other highlights of the meeting, Cathy Williams (University of Bristol), presented evidence for sub-types of Cerebral Visual Impairment (CVI) in children. It has become apparent recently that a surprisingly high proportion of children in main stream classrooms may have such brain based visual problems.

My own talk about the Eyelander game was the last presentation of the conference! But everyone stayed right to the end and seemed to really enjoy it! Eyelander is a gamified version of compensatory visual search training for children with loss of vision on one side (hemianopia) . Selective loss of vision to the left or right might occur following brain injury or neurosurgery, but may also be found in many children with CVI (see above).

I really enjoyed the CVRS meeting. It was great to meet so many new people. In fact, it was one of the friendliest and most enjoyable meetings I’ve ever been to, so I will be sure to go again in 2 years time!

Eyelander game at VIEW conference

Timothy Hodgson Conferences, Eyelander, Impact , ,

Recently I attended the VIEW conference for Visual impairment (VI) specialist teachers and professionals in Birmingham, to raising awareness of our Eyelander online game for children with partial visual field loss (Hemianopia).

Eyelander is based on visual search training programmes that have been shown to be effective in improving functional visual abilities in adults that suffer from Homonymous visual field loss following stroke. In the game you have to search for coloured shapes amongst “distractor” shapes, with varying levels of task difficult as the game progresses. As you complete more searches your character (the “Eyelander”) make progress in escaping a volcanic desert island.

The game is available to play via a web browser, either on a computer with a mouse / laptop or a touch screen device. Its efficacy was validated via a published small scale trial in a group of children and young people with well defined hemianopia, suggesting playing the game every day over a period of 4 to 6 weeks can lead to improved visual abilities.

There was lots of interest in the game from VI teachers, who feel that partial visual field loss and problems seeing on one side is very common in the children they work with. Estimates for number of children with some form of brain based visual impairment (also known as Cerebral Visual Impairment or CVI) and many of these may have visual field problems. Given this we are keen for more parents, children, teachers and others working with children with VI to know about Eyelander and to give it a go.

So visit www.eyelander.co.uk and register to play!

Visual Attention and Paeleolithic Stone Tools

Timothy Hodgson General news, Publications, research

This month we published a study describing how people direct eye movements during viewing of ancient stone tools. The work was led by Maria Silva Gago, Emiliano Bruner and other researchers from CENIEH University of Burgos Spain together with myself and former Lincoln PhD student Flora Ioannidou (now at University of Aberdeen).

The research used eye tracking and the “mouse click” attention tracking technique to measure which areas of stone tools attracted peoples interest most. High resolution photographs of Paeleolithic hand axes (example right), along with much more ancient (approximate 2 million year old) roughly worked tools (example below) were shown to participants. We found that people’s attention was drawn to the “knapped” surfaces of  tools, as well as areas such as the base where the tool would normally be grasped. This was the case even though participants were just viewing pictures and not handling the objects and weren’t told the objects were tools.

We also ran the images through a computer model which calculated the”salience” of different regions of the images.  Some very influential models of vision suggest that attention is simply attracted to regions that stand out visually from the background (i.e. are more “salient”), but the computer model did not seem to explain our results very well. Instead, we think it was how the different parts of the tool might be grasped and used, rather than just how visually interesting it was, that was directing the viewers’ eyes.

The results support the theory of object-action affordances proposed by James J Gibson in the 1970s. He suggested that the brain very quickly detects features of objects that are relevant for action, priming a tendency for us to carry out the associated action. One possibility is that through evolution our ancestors’ brains became increasingly sophisticated at detecting action affordances in stone objects. This lead in turn to the manufacture of more sophisticated tools with enhanced features designed to activate action affordances. This in turn may have caused further development in the brain’s object-action affordance network in an ongoing process of coevolution between human cognitive capacities and tool complexity.

The full paper is published in the journal Perception and can be read online here.

Some example eye movement sequences recorded in the study are shown below.

Orienting to social cues in Parkinsons

Timothy Hodgson General news, Impact, Parkinsons, Publications, social neuroscience

This month we published a paper in the journal Experimental Brain Research reporting how eye movements are influenced by social cues in people with Parkinsons disease.

Previous studies have suggested that Parkinsons patients have problems in directing visual attention due to loss of the chemical dopamine within the basal ganglia of the brain, but no one has specifically looked at whether they have particular problems with social cues. This question is important as problems with processing social information may lead to difficulties in everyday life for people with Parkinsons. It is also a question of scientific interest as it has been suggested that we have specialised brain pathways for processing social information (the so-called “Social Brain hypothesis”).

We used a task in which pictures of someone else’s eyes, arrows and pointing fingers are shown on a computer screen, whilst people track a spot jumping around the screen with their eyes (see picture; you can see a video of the task here). Often people make an eye movement by mistake in the direction indicted by the eyes, arrows or fingers, even when they are meant to respond directly at the target (the little black spot) and ignore the pictures. We found healthy adults made more of these errors with pointing finger cues compared to the other cue types (suggesting pointing fingers provide a particularly strong cues to eye movements) whereas people with Parkinsons made similarly high errors for all 3 cue types.

Although not specifically better or worse for socially relevant cues (eyes / fingers), Parkinsons patients clearly had difficulty in suppressing their distracting influence. This suggests the basal ganglia plays a role in controlling eye movements in response to social and non-social cues. But this doesn’t mean that people with Parkinsons don’t have particular problems with maintaining attention in social situations. On the contrary, social interaction might often take place in a busy environment, with lots of sensory information competing for attention. These deficits in the control of eye movements might therefore lead to difficulty in social interaction and might impact on patients’ quality of life.

A link to the paper can be found here