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Perceiving Speed and Speed Change in the World Around Us

A lecture by Abigail Lee, School of Psychology and Neuroscience

Thursday 19 April 2018, Arts Lecture Theatre

When driving a car, judging the relative speed of other vehicles moving around you can be very important, but it is also relatively easy. When another car is travelling faster than you, it rapidly travels past you, but when a car is moving slower than you, you get stuck behind it.

However, it is much harder to judge a change in speed, which is why we need brake lights as a clear signal that the vehicle in front is slowing to prevent collisions. Why would perceiving a sudden change in speed be harder than perceiving speed? If we can perceive an object that is moving quickly and an object that moves slowly, why is it difficult for us to perceive an object that travels quickly and then slowly?

Abigail has investigated this using two different tasks. Both tasks involve using computers to carefully design short videos for people to view. Their responses to what they see are then collected. This allows us to ask questions about what their brains do with the visual information, for example, what is the smallest difference in the speed of two objects that participants can tell the difference between? The first task used was a speed discrimination task, where a person views two objects moving one after the other and picks which one had moved faster. The second task was a speed-change discrimination task, which is similar to a speed discrimination task, but one of the objects suddenly changes speed as it moves. The observer has to decide which object had changed speed. Abigail has found that speed-change discrimination is much harder than speed discrimination in experimental conditions. Abigail will discuss what the brain may be doing to cause this phenomenon and, as a result, why we really do need cars to have brake lights.

Reserve Your Place

This event is open to all University of St Andrews students, postgraduates, and staff and is free to attend. Places should be reserved in advance - to reserve your place, please email

The event will feature two lectures - by Abigail and by Maneesh Kuruvilla. The lectures start at 15:30 Thursday 19 April 2018. The lectures will be held in the Arts Lecture Theatre in the Arts Building - number 31 on the University Map - and will be followed by a drinks reception.

About Abigail Lee

Abigail Lee

Abigail Lee is a doctoral researcher in the School of Psychology and Neuroscience at the University of St Andrews. Her research looks at how people perceive objects moving towards them in three dimensions and the processing networks behind this.

Abigail's doctoral research is supervised by Professor Julie Harris and Dr Justin Ales.

Learn More

St Leonard’s Doctoral and Postgraduate College

The Bute Building, Queen’s Terrace
St Andrews
KY16 9TS
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