Eye-tracking insights

Here at Southampton we have one of the world’s leading groups in human vision and cognition. We find out how our cutting-edge research is shedding light on two very diverse areas: improving airport security and understanding language processing.

Improving airport security

Tracking and analysing eye movements can give researchers insights into how people tackle a variety of tasks. Eye-tracking research at Southampton is helping to keep airports safer, something that is high on the agenda in the wake of recent terrorist attacks.

Southampton researchers are investigating how to enable airport security staff to detect threats more effectively. Airport security staff view X-ray images of baggage, searching for multiple types of weapons such as guns, knives and explosives. “This is a challenging task because they are working in a relatively visually impoverished environment, where most of the colour and other visual cues such as depth are removed from the images. This makes it difficult to tell where one object ends and another begins, so the interpretation of these images is a specialist skill,” says Simon Liversedge, Professor of Experimental Psychology.

Using the University’s state-of-the-art eye-tracking facilities, the team of researchers working within the Centre for Vision and Cognition (CVC) have taken extensive measurements of people’s eye movements to find out whether, and how, baggage screening techniques could be improved.

Within an X-ray image, different materials that could potentially pose a threat, such as metal and explosives, show up as different colours. In collaboration with Dstl, the CVC team have shown that searching for two different colours simultaneously is more difficult than carrying out separate searches for each of the two colours. The research findings have been used to inform the US Department of Homeland Security’s aviation security research and policy, and are being used on further projects in relation to anti-terrorism and defence strategies employed by the UK Ministry of Defence (MoD).

Funded by the Economic and Social Research Council and the Leverhulme Trust, the CVC team are currently working with the Department for Transport, Dstl, the International Air Transport Association and Egremont to look at how organisation of baggage screening and training for baggage handlers can be improved.

“We are looking at whether we improve people’s abilities to identify objects more effectively if they are given depth cues in X-ray images – similar to the effect you see when watching a film in 3D – rather than purely flat images,” says Simon. As part of this project the team has worked with the Department for Transport at Manchester Airport, looking at the types of issues screeners face in an airport scenario in real life and how they relate directly to doing the job.

“This type and scale of study has never been done before and the findings will be relevant to airports across the UK,” says Simon. “We are now planning to investigate these issues in airports across Europe and internationally.”

Understanding how we read and process languages

Our eye-tracking research is also having an impact on a completely different area: how we process and read languages. There are around 6,500 languages spoken in the world. Understanding how we process them is intriguing because despite their vast differences, wherever we are born we tend to learn our ‘mother tongue’ very easily.

Working with Tianjin Normal University in China and the University of Turku in Finland, Simon and his team have recently completed a study investigating whether some languages are more efficient at conveying meaning than others. To achieve this, they compared how long it takes people from different countries to read and process their own native languages.

“We chose to study English, Finnish and Chinese because the written forms of these languages are very different: there are no spaces between Chinese words, and Finnish is an agglutinative language with several sub words grouped together, whereas in English, single words are usually separated with spaces,” says Simon.

The researchers found that although there were pronounced differences in eye movements when people read the sentences in the three languages, there was no difference in the time it took them to read the sentences.

“We have shown that it doesn’t matter whether a native Chinese reader is processing Chinese, or a Finnish native reader is reading Finnish, or an English native reader is processing English; in terms of comprehending the basic propositional content of the language, one language is as good as another,” says Simon.

The team now plan to analyse the data again, this time looking at smaller units such as nouns, clauses and phrases that convey the same meaning in the three languages.

These findings could give insights into how we can learn second languages more effectively. “If we consider the Chinese language, there are no spaces between the words, whereas in English and Finnish there are. So if word spacing is central to your native language, it might be easier for you to learn Chinese if spaces are put in between the words to help facilitate your learning,” Simon adds.

To find out more about Simon’s research, visit http://www.southampton.ac.uk/psychology/about/staff/spl1.page

Centre for Vision and Cognition: http://www.southampton.ac.uk/psychology/research/groups/centre_for_vision_and_cognition.page