Vacate - To set aside.

Validity - The extent to which a test measures what it was intended to measure.

Valium - A depressant drug of the benzodiazepine family that relieves anxiety.

Variable - In an experimental setting, a factor that varies in amount and kind.

Variable-Interval Schedule - A schedule of reinforcement in which a reinforcer is delivered for the first response made after a variable period of time whose average is predetermined.

Variable-Ratio Schedule - A schedule of reinforcement in which a reinforcer is delivered for the first response made after a variable number of responses whose average is predetermined.

Venire - A writ summoning persons to court to act as jurors.

Ventral Tegmental Area - The group of dopamine-containing neurons that make up a key part of the brain reward system. The key targets of these neurons include the nucleus accumbens and the prefrontal cortex.

Venue - The geographic area in which a court has jurisdiction. A change of venue is a change or transfer of a case from one judicial district to another.

Verbigeration - Stereotyped and seemingly meaningless repetition of words or sentences.

Verdict - Formal decision by a jury or a court based on the facts of a case.

Vesicles - Tiny sacks within axon terminals that produce, release, and store neurotransmitters.

Vestibular Sense - The sense that tells how one's own body is oriented in the world with respect to gravity.

Veterans Administration - The federal agency which administers a system of benefits for veterans and their dependents.

Vicodin - A medication widely used for moderate pain which contains hydrocodone and acetaminophen.

Visa - An official endorsement on a document or passport denoting that the bearer may proceed.

Visual Cortex - A brain region in the back of the head that allows us to perceive the visual information gathered by our eyes.

Visual Hallucination  - A hallucination involving sight, which may consist of formed images, such as of people, or of unformed images, such as flashes of light. Visual hallucinations should be distinguished from illusions, which are misperceptions of real external stimuli.

Void - Invalid; a void agreement is one for which there is no remedy.

Voidable - Capable of being declared invalid; a voidable contract is one where a person may avoid his obligation, as a contract between an adult and a minor.

Voir Dire - Jury selection process of questioning prospective jurors, to ascertain their qualifications and determine any basis for challenge. Literally, to speak the truth.

Volley Principle - An extension of frequency theory which proposes that when peaks in a sound wave come too frequently for a single neuron to fire at each peak, several neurons fire as a group at the frequency of the stimulus tone.

Voluntary Bankruptcy - A proceeding by which a debtor voluntarily asks for a discharge of his debts under the Bankruptcy Code.

Voluntary Payments - Payments made directly to a custodial parent by the non-custodial parent without a child support order established. These payments are considered as gifts to the custodial parent.

Voluntary Permanent Surrender - An agreement between the parents, guardian, or other persons having custody of a child and a public children services agency or private child placing agency in which the child is surrendered into the permanent custody of the agency, allowing the agency to take and care for the child, place the child in a family home, or place the child for adoption.

Voluntary Transfer - A transfer of a debtor's property with the debtor's consent.

Voyeurism - Peeping; one of the paraphilias, characterized by marked distress over, or acting on, urges to observe unsuspecting people, usually strangers, who are naked or in the process of disrobing, or who are engaging in sexual activity.

Vulnerable Populations - Groups of people who, as a result of life conditions and circumstances, are at increased risk for being harmed by specific social, environmental, and/or health problems, making them more susceptible to disempowerment, social injustice, and a lower quality of life.