Making sense of ourselves
Making sense of ourselves

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Making sense of ourselves

3.1 What do visual illusions tell us about how we process information?

Our visual and perceptual systems work together to help us to make sense of our surroundings. Visual illusions allow us to investigate how the two systems work together and also to highlight how some of the cortical shortcuts taken can lead to an altered perception of a stimulus.

In the four parts of this activity you will get the chance to try out a few illusions before considering the underlying processes that they reveal.

Activity 4 Visual illusion of context

Timing: This activity will take about one hour.

Some illusions inform us of the effect of context and surroundings on visual processing. In the example below, participants are asked to judge which circle is darker in colour. The circles in the centre of each of the squares appear to be different in colour: the circle on the left appears lighter than the circle on the right.

Now click on either of the arrows in the figure to remove the coloured surrounds. As you can see, both circles are the same colour.

Active content not displayed. This content requires JavaScript to be enabled.
Interactive feature not available in single page view (see it in standard view).

Why might this be the case? Note down what you think might cause this illusion, or any thoughts you have on your experience of it.

To use this interactive functionality a free OU account is required. Sign in or register.
Interactive feature not available in single page view (see it in standard view).

Discussion

Now click on either of the arrows in the figure to remove the coloured surrounds. As you can see, both circles are the same colour. Your perception in this case is affected by the colour of the surrounding shapes. The circle on the left is surrounded by a darker colour (blue) which makes us perceive it as being lighter. The circle on the right is surrounded by a lighter colour (pink) which makes us perceive it as being darker. When placed next to one another and compared, these context effects come into play and the colours of the circles appear different. When the surrounding colours (the context) are removed, the circles are revealed to be identical in colour.

DE200_4

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371