Electroencephalography (EEG) and Event Related Potentials (ERP)
Electroencephalography (EEG) is a tool that allows us to non-invasively record electrical brain activity from the surface of the scalp. We fit participants with an elastic cap fitted with a number of electrodes. The recorded electrical activity reflects the summed activity of thousands or millions of neurons that fire in synchrony. The nature of these brain waves gives us useful information about a person’s current state.
We can also use EEG to examine the electrical brain activity associated with specific cognitive processes. We examine the pattern of brain activity tied to events (e.g., seeing an image, or making a mistake) while participants perform a task. These patterns are called event-related potentials (ERPs).
When we experience an emotion it is not only expressed in our mind but also in our body. Think of the butterflies in your stomach before you give a speech, or the smile you can’t wipe from your face before reuniting with an absent loved one. We use psychophysiology to measure these physical components of emotion. In the CANLab we do this using sensors on the surface of the skin that measure heart rate, skin conductance (due to sweat) and muscle movement.
The eyes are the window to the soul. When we look at the world, our eyes don’t move smoothly across the scene. Instead they jump from spot to spot, lingering in the places that are most interesting, or most important, or most relevant to our current goal. In the lab, we use eyetracking to help us identify those features or objects that are most relevant to people, and to determine the role of emotion in guiding our looking behaviour.
Using an eye tracker, we can measure pupil size while people perform various tasks. Pupil size is linked to the release of certain neurotransmitters in the brain that are involved in cognitive and emotional processing. Therefore we can track moment-to-moment changes in effort and emotional arousal to learn about the time-course of cognitive processing.
Transcranial Magnetic Stimulation (TMS)
TMS is a safe non-invasive technique that temporarily influences brain activity. A magnetic coil is placed on the head, which sends out electromagnetic pulses. These pulses stimulate the brain, causing neural depolarisation or hyper-polarisation and temporarily disrupting cortical activity. Alongside neuroimaging and neurotracking techniques, TMS enables us to target specific areas in the brain to examine their role in human functioning. To participate in a TMS study, you will first get an MRI brain scan (and will receive a picture of your brain on completion of the study).
Virtual Reality (VR)
Virtual reality provides unique opportunities to psychological scientists who seek to study a wide range of phenomena – from fundamental cognitive and emotional processes, to social interactions, to therapeutic and educational applications. Currently, we use VR to immerse participants in environments designed to evoke specific emotions, in order to better understand how realistic emotional experiences impact performance on concurrent cognitive tasks.