To begin, please fill in the details box below (this may take a little while to load in) and click on submit.
Your computer should then download a java programme. It is only 29K long but it will take a few moments to load in, depending on the speed of your connection.
When the programme has loaded you should see two boxes below. In the left box are drawings of six leaves. These are all from one of two classes of differently shaped leaves. We have chosen one class as the 'good' leaf class. For each set of six leaves that you see, you must decide if they are from the good or the bad leaf class. At first you will have to guess. With practise, though, you will hopefully learn by trial and error until you can do the task accurately.
If you think that the leaves are from the GOOD class, click now on the box with leaves in it. If you think that the leaves are from the BAD class, click now on the other, empty box. As soon as you have done this, a tick or a cross appears to say whether your decision was right or wrong. Now click again to get the next set of leaves.
The line of ticks at the bottom of the screen shows how many trials you have got right in a row. If you get one wrong, a cross will appear, and you will go back to having no ticks. You have to get fifteen trials in a row right before you can start on the next block of the experiment.
There are six blocks of trials altogether. Different leaf classes are used in each of the blocks, but the instructions for each block are the same. The first block of trials is easy. It is designed to help you understand the instructions. Now try to guess whether the leaves below are from the good or the bad class.
If you are not connected to the net or something goes wrong, the experiment will abort.