In our daily lives, our visual field is the most robust source of sensory information. In making decisions between choices
that are in front of us, our eye movements and gaze direction says a lot about what we pay attention to. The visual information we attend to influences the decisions we make in the present and then those decisions can shift our attention in the future. In our lab, we use small cameras to track the motion of the pupil relative to the head and cornea, so that we can determine gaze direction and track eye movements in real time.
Event-related Potentials (ERP):
Many cognitive processes can be evaluated using brain imaging. Electroencephalography (EEG) measures the electrical signals produced by certain brain cells in association to specific behaviours, such as visually perceiving choice options when making a decision. The temporal precision of EEG makes it suitable to study fast processes occurring in the brain. Using EEG, we can time-lock the electrical signals to controlled events in an experiment, and by averaging this signal over trials an event-related potential (ERP) is computed. ERPs can be compared between conditions, to see which factors have an effect on the millisecond long cognitive processes which occur in decision-making.
Functional Magnetic Resonance Imaging (fMRI):
Often in decision-making research, we want to associate the processing of certain features of choice (e.g., the value or probability) to specific brain regions. Functional magnetic resonance imaging (fMRI) records the metabolic changes in blood flow to certain brain regions, allowing us to observe with high spatial resolution,which regions of interest are active during a behaviour. For instance, brain activity can be measured during decision-making trials, along with the period before and after trials, giving us an |idea of the participants’ affective and cognitive processes leading up to and after the decision.
Many of our decision making abilities and outcomes can be measured in computer coded tasks. These behavioural measurements include response time and accuracy. We can examine the effect of pre-decision stimuli, such as high and low arousal audio clips, on these measures. Once analyzed, the results have the potential to validate or build upon previously studied decision-making models.
In real life, our emotional state influences our decision making process by assigning a valency (i.e., positive or negative) to choices. For many emotional responses a physiological reaction is elicited. These can be recorded and may give us insight into the affect that participants are experiencing during decision making, which provides objective information about how their emotional states modifies their decisions. In the MADlab, the physiological measures we use allow us to measure stress and arousal in participants. These include:
- Galvanic Skin Response
- Heart Rate
- Cortisol Assay