 Between 70 and 80 healthy, English speaking, right-handed, adults between the ages of 18 and 45 participated. Attempts were made to include equal numbers of men and women to permit the broadest generalization to the population and to permit direct assessment of gender effects, an issue that has received considerable attention recently regarding the neurobiology of affective processes. Subjects were not excluded on the basis of ethnicity, gender, or sexual orientation. Healthy participants were recruited via local advertisements, including email broadcasts such as the Harvard Hospital and Partners Healthcare systems, internet advertisements, and posting of IRB-approved flyers in various community centers. IRB-approved print advertisements were posted in local newspapers. 