Additional Study Information: We are doing this research study to learn more about brain waves, and how they influence perception and cognition. We are interested in understanding how the brain works, and how sensory inputs such as sounds and pictures are being processed in the healthy brain. We will ask you to perform a mental task while EEG data are recorded. EEG measures brain electrical activity on the scalp (that is, brain waves) using sensors that connect to the EEG device. You will wear a cap, similar to a swim cap, that has sensors connected to it. We will place a special gel on the sensors to help create contact between your scalp and the sensors so your brain signals can be recorded. The gel is easily washed out after the recordings. The EEG data collection will take place in a small, office-like space in the laboratory. Including preparation the experiment would will take around 3 hours.