The Hershey Company is interested in investigating the effects of various chocolate beverages on brain physiology and cognitive function. The main substances in the drinks that are known to influence the brain are caffeine and related chemicals such as theobromine. Caffeine and chemicals related to caffeine are all naturally occurring and all potentially alter brain physiology. This study will evaluate changes in brain blood flow and cognition following the consumption of drinks with various combinations of the Primary Ingredients. The study proposed here will evaluate ingredients in a 4-arm cross-over double-blind design in an attempt to understand the differential effects of these compounds in chocolate drinks.

Inclusion Criteria:

• Consume 200-500 mg caffeine daily
• Willing and capable of signing the informed consent
• Willing to attend 4 testing sessions that will take 4-6 hours each AND will be at least 10 days apart
• Willing to abstain from caffeine for 16 hours before each testing session
• Willing to and able to have MRIs

Exclusion Criteria:

• As determined from the medical screening session

  • active neurological dysfunction (such as a major Axis I psychopathology, Alzheimer's disease, Parkinson's disease, prior history of stroke, epilepsy, or serious central nervous system (CNS) trauma)
  • attention deficit hyperactivity disorder (ADHD)
  • migraines
  • hypertension
  • diabetes
  • peripheral vascular disease
  • taking vasoactive medications (such as anti-hypertensive medications)
  • depression that has not been on a stable medical treatment for at least 4 weeks
  • Pregnancy
  • Allergy to chocolate, peanuts, tree nuts, egg, soy, milk, wheat

• Color blindness

• Individuals who are or potentially may be cognitively or psychologically impaired, or who otherwise have a limited capacity to provide consent