Select the oval object as fast as you can without making mistakes!


Help us understand better how humans detect objects correctly under different conditions.

You will see two marble blocks. On one of the blocks there will always be an oval object like the ones indicated by the red arrow below (the objects on the other block will change on every trial, but they will never be an oval). Note that the size of all the objects will change on every trial; your task is to identify the oval object regardless of its size.

Your task is to press "1" or "2" on your keyboard to indicate the number of the block where the oval object is.

You should do this as quickly as you can without making mistakes. You'll have up to 2 seconds to respond. We'll let you know if you were too slow. Please mind that your responses will be useful only if at least 80% of them are correct. We will give you feedback on each trial (green = correct, red = wrong).

Note that the This HIT is short (less than 6 minutes), so please try to stay focused. It's important that you pay attention to the screen all the time.

Make sure your browser window is maximized. You must be on a laptop or desktop computer to participate in this HIT (no cellphones or tablets). Click "Start Experiment" to begin with a few practice trials.

By completing this survey or questionnaire, you are consenting to be in this research study. Your participation is voluntary and you can stop at any time.