Clinical Research Directory

Inclusion Criteria: Between the ages of 20 and 35 years old Exclusion Criteria: * a neurological impairment or disorder, learning disability, or psychological syndrome that might affect EF performance (such as ADHD) * inability to understand the task instructions (which are in English), or difficulty hearing the instructions, seeing the stimuli, or executing a manual response. * a serious adverse event during pregnancy or birth. * an injury (such as a head injury with loss of consciousness) that might affect EF performance. * a major trauma that might affect current EFs and stress responsivity * undue current life stress level * taking any medication that affects thinking, memory, mental clarity, or any other EF ability. * taking any medication that influences circulating gonadal hormone levels (such as oral contraceptives \[birth control pill\]). * having taken such medications within the preceding four months. * smokers * use of recreational drugs or consumption of alcohol 24 hours prior to the testing sessions * women without a period that occurs roughly every month (predicting the onset of the next menses in women who don't have their period monthly is difficult) * women who are pregnant or who are nursing. * having the eye problem glaucoma * having a heart condition * being anxious, tense or agitated * taking or have taken within the past 14 days an anti-depression medicine called a monoamine oxidase inhibitor or MAOI. * taking pressor agents (for hypotension treatment) * taking coumarin anticoagulants * taking anticonvulsants (phenobarbital, diphenylhydantoin, primidone) * taking phenylbutazone (nonsteroidal anti-inflammatory drug) * taking tricyclic antidepressants (imipramine, desipramine) * taking cold or allergy medicine that contain decongestants * being allergic to anything in either the MPH or Vitamin C capsules (methylphenidate HCL, ascorbic acid, lactose, gelatin, Titanium dioxide, D\&C Red #28, FD\&C Blue #1, FD\&C Red #40)