Overview

This study seeks to understand individual differences in personality, brain function, and behavior.

Study hypothesis:

• A stronger sign-tracking bias will be associated with a bottom-up processing style characterized by less adaptive attentional- and impulse-control as well as hyperactive reward processing, whereas a stronger goal-tracking bias will be associated with a top-down processing style characterized by strong attentional- and impulse-control as well as normative reward processing.

Eligibility

Inclusion Criteria:

• 18-20 years old at baseline
• Right-handed
• Medically/physically able to give informed consent
• English-speaking
• Substance use is free to vary, but for participants with a history of substance use, ≥ 1 use of cannabis (including less than a full dose)

Exclusion Criteria:

• Acute or chronic medical or neurological illness (e.g., diabetes, epilepsy, migraine)
• History of psychosis in self or first-degree relative
• Current treatment for substance use disorder
• Current or past 6-month treatment with centrally acting medications (not including attention deficit hyperactivity disorder (ADHD) medication)
• Intelligence quotient (IQ) < 70
• Lifetime history of head trauma with loss of consciousness > 5 minutes
• Reliance on glasses to be able to read small text at a distance of approximately 30 inches
• Colorblindness
• MRI contraindication (e.g., pregnancy, metal implants, claustrophobia) per protocol