AB Design

A single subject research design that contains one baseline (A) and one treatment (B).

ABAB Design

A single subject research design that contains a baseline (A1), treatment (B1), a second baseline (B2) and a second treatment phase (B2)

Alpha (lowercase)

The abbreviation for probability of error in statistical results. See Type I Error. (a)

Alternative Hypothesis

The hypothesis that states there is a difference between two or more sets of data.

Absolute Zero

Characteristic of a scale of measurement that contains a point where the scale has no value.

Accommodation

The creation of new cognitive schemas when objects, experiences, or other information does not fit with existing schemas.

Action Potential

The firing on a neuron.  Occurs when the charge inside the neuron becomes more positive than the charge outside.

Acetycholine

A neurotransmitter associated with voluntary movement, sleep and wakefulness.

Aggressive

An interpersonal style where only the immediate needs of the self are considered rather than the needs of others.  (As opposed to passive or assertive)

Agoraphobia

An anxiety disorder characterized by an intense fear of leaving one's home.

All or None Law

Either a neuron completely fires or it does not fire at all.

Alpha (lowercase)

The abbreviation for probability of error in statistical results. See Type I Error. (a)

Alternative Hypothesis

The hypothesis that states there is a difference between two or more sets of data.

Altruism

Behavior that is unselfish and may even be detrimental but which benefits others.

Amnesia

Loss of memory.  Usually only a partial loss such as for a period of time or biographical information.

Amygdala

A part of the brain's limbic system that attaches emotional significance to information and mediates both defensive and aggressive behavior.

Anal Expulsive Personality

Stemming from the Anal stage, a child who becomes fixated due to over control transfers his or her unresolved anal (or control) issues into characteristics such as cruelty, pushiness, messiness, or disorganization.

Anal Retentive Personality

Stemming from the Anal stage, a child who becomes fixated due to under control transfers his or her unresolved anal (or control) issues into characteristics such as compulsivity, stinginess, cleanliness, organization, and obstinance.

Anal Stage

Freud's second stage of psychosexual development where the primary sexual focus is on the elimination or holding onto feces.  The stage is often thought of as representing a child's ability to control his or her own world.

Analysis

See Psychoanalysis.

Analysis of Variance

An inferential statistical procedure used to test whether or not the means of two or more sets of data are equal to each other.

ANOVA

Analysis of Variance.

Anxiety

The physiological and psychological reaction to an expected danger, whether real or imagined.

Aphasia

The impairment of the ability to communicate either through oral or written discourse as a result of brain damage.

Approach-Approach Conflict

The conflict presented when two opposite but equally appealing choices are available but can not both be obtained.

Approach-Avoidance Conflict 

The conflict presented when the best positive choice will result in a negative outcome as well as positive.   

Arousal Theory

The theory stating that we are motivated by our innate desire to maintain an optimal level of arousal.

Assertive

Style of interpersonal interaction where both the needs of the self and others are considered.  (As opposed to passive or aggressive)

Assimilation

Incorporating objects, experiences, or information into existing schemas.

Associations

The phenomenon in learning that states we are better able to remember information if it is paired with something we are familiar with or otherwise stands out.

Attachment

The strong bond a child forms with his or her primary caregiver.

Attribution

An idea or belief about the etiology of a certain behavior.

Attribution Theory

The theory that argues people look for explanation of behavior, associating either dispositional (internal) attributes or situational (external) attributes.

Authoritarian [parents]

Parenting style focused on excessive rules, rigid belief systems, and the expectation of unquestioned obedience.

Authoritative [parents]

Parenting style focused on setting reasonable rules and expectations while encouraging communication and independence.

Autonomic Nervous System

Part of the peripheral nervous system that regulates the involuntary actions of the body (e.g., breathing, heart rate, blood pressure, pupil dilation).  Also regulates the Fight or Flight Phenomenon.

Availability Heuristic

A rule of thumb stating that information more readily available in our memory is more important than information not as easily accessible.

Aversion Therapy

A type of behavioral treatment where an aversive stimuli is paired with a negative behavior in hopes that the behavior will change in the future to avoid the aversive stimuli.

Avoidance-Avoidance Conflict

The conflict where both possible choices have an equal negative outcome.

Axon

The tail-like part of the neuron through which information exits the cell.