This month I attended the London meeting of the Experimental Psychology Society. I presented preliminary analysis of some eye movement data we recorded whilst people perform a task based upon a widely used computerised neuropsychological test of spatial working memory (Cambridge Cognition Ltd’s CANTAB SWM test).
Spatial working memory refers to the short term storage of information in memory about where things are in space for guiding our behaviour and actions. In the Cantab task “tokens” are hidden under boxes on a screen and participants have to search for them by clicking with a mouse on the boxes and remember where they found the tokens to guide subsequent box selections (as tokens are never hidden under the same location twice). As you can see in the videos here: http://www.youtube.com/watch?v=PStfmW6q_c0 participants make quite a lot of eye movements in the task! So the challenge has been to make sense of how eye movements are guided. Are they shaped by the memory of where tokens have been found, such that the eyes help to keep track of the route covered? Or do they exclusively plan a search route ahead selecting the next box to be clicked on? Might eye movement measures extracted from the task be useful in assessing memory problems?
Our analysis suggests that most eye movements look ahead and select the next box to be clicked on well in advance of the mouse click which reveals its contents. However, particularly in a few participants, the eyes also get drawn back to locations where tokens have already been found, even if they don’t click on the box, indicating that they do actually remember that a token hasnt been found there (see here for a nice example: http://www.youtube.com/watch?v=xtoCLcqtHnM). These subjects were more likely to go on to make lots of actual click errors in the most difficult version of the task though, suggesting eye movements measures may be more sensitive than just mouse clicks.
We have more analysis and work to do with this task and hope to get some people with Parkinsons to do the test as we think they may show subtly different patterns of eye movements in the task to otherwise healthy individuals.
Our Knowledge Transfer Partnership with the WESC foundation Exeter is nearly half way through its two years and is getting really exciting. Dr Jonathan Waddington, post-doctoral neuroscientist and lead researcher based at WESC recently visited the Perception Action Cognition research group in Lincoln to up date us on progress. The visual search computer game is nearly ready to move into the next stage of an evaluation trial to see whether it can deliver improvements in functional vision in children with visual field loss. See here for a more details via the WESC research and development blog:
Next week we will be presenting our work on orienting to socio-biological cues in children at the 17th European Conference on Eye Movements in Lund, Sweden.
At last years Lincoln Summer Scientist event we asked children to play a game in which they followed a cartoon bee jumping to the left or right with their eyes whilst distracting pictures of arrows, pointing fingers and someone else’s eyes gazing to the left or right were shown in the middle of the screen. We tracked their eye movements with an Eyelink 1000 eye tracking system and measured how quickly they made saccades to follow the bee.
We found that the youngest children (4-5 year olds) showed a large “congruency” effect for pictures of pointing fingers such that their speed of looking was slowest when the bee jumped in the opposite direction to that in which the hand pointed. Surprisingly, although the pre-schoolers weren’t similarly affected by pictures of eyes and arrows, older fellow summer scientists showed an equally strong congruency effect for all three types of cue (hand, eye and arrows).
The results are potentially very interesting and important in respect to understanding the best ways to direct young children’s attention quickly and effectively in an educational context as well as keeping them away from harm inside or outside of the home, but they might also have more profound implications. Rather than having hard wired “social brain” systems for processing socio-biological stimuli as suggested by some theorists, instead the brain may learn to form fast connections between what we see and what we do in early childhood. It just happens that pointing fingers may be among the first cues children learn to use in this way.
We’re looking forward to finding out what other researchers think of our results in Lund and plan to replicate the finding at this years Lincoln Summer Scientists event. The work is carried out in collaboration with Nicola Gregory (Bournemouth University Face Research Centre). The work is part supported by the WESC foundation for Childhood Visual Impairment.
In our most recent research paper (published this month in the journal Neuropsychologia ), we investigated how people with Parkinsons perform a computerised eye movement rule switching task, which we have used previously in patients with frontal lobe damage (see U-tube video: and Summer Scientist 2012).
Many every day tasks require us to learn to make links between what we see and where we look with our eyes. We also need to be able to switch between performing one task or another (e.g. making a cup of tea, reading the newspaper and then answering the telephone) and learn new skills such as preparing a new recipe or learning a new game or sport.
Unlike patients with frontal lobe strokes, People with Parkinsons didn’t show any big problems in switching between stimulus-saccade “rules” (e.g. blue stimulus = look left), but were slower to learn a new rule by trial and error learning compared to participants without Parkinson. This suggests that the brain circuits and chemicals affected in Parkinsons play a role in this ability and that people with Parkinsons may have problems learning new visuo-spatial tasks over and above the obvious difficulties the condition causes with movement.
Please contact me if you would like a reprint of the paper or would like to know more about this research.
Next Tuesday I will be giving my public inaugural lecture at the University of Lincoln. I have chosen to focus on ways in which human saccadic eye movements have and may in the future have an impact beyond academia. I will explain how eye movements can change the world in 4 different ways:
1. Eye movements themselves change our perception of the world. In a sense we all see the world differently in a way affected by our individual eye movements;
2. Visual search training, improving the efficiency with which we use eye movements, can be used to improve functional vision in adults and children with visual problems;
3. Research into attention and eye movements might be brought to bear to improve navigational cues in our visual environment, such as road signage;
4. Finally and perhaps most exciting is that saccadic measures might not only be valuable in the assessment of patients with neurological disorders, but could potentially be used to provide an early diagnosis of such conditions as Parkinsons and Dementia.
I am looking forward to talking to a general audience including members of the public, colleagues, friends and family and hope they will agree that eye movements can indeed change the world!
More details of the lecture and how to book are given here: