Point Subtraction Aggression Paradigm (PSAP)
Background
The Point Subtraction Aggression Paradigm (PSAP) is a laboratory-based behavioral test used to measure human aggression. The task was designed by Don R. Cherek and colleagues in 1997 as a two-player simulated game to investigate aggressive behavior in response to non-physical provocation.
In the game, a participant plays against a fictitious competitor (aka computer confederate) to earn points that can be turned into money. The participant and competitor (aka computer) can steal and protect their winnings from each other. However, while participants get to believe the competitor can steal their money and keep it; participants can only "steal" from the competitor but not add the stolen points to their winnings. Because stealing provides no financial or tangible benefit for participants and serves only to cause an aversive consequence for the other person, the number of "steals" is used as a direct behavioral index of reactive aggression.
Task Procedure
Participants playing the PSAP game get three behavioral choices: (a) work to earn points, (b) work to steal points or (c) work to gain protection.
- Earn points: press game button 'A' 100 times.
- To steal points: press game button 'B' 10 times (Note: participants also gain protection from this option, but this is not made explicit to them)
- To activate a time-based protection interval (default: 250 seconds): press game button 'C' 10 times
Once participants decide on an option, no other choices are possible until the required amount of responses have been made. For example, if participants select option A from the choice menu, choice B and C vanish, and participants must press game button 'A' consecutively for 100 times before option B or option C become available once more.
In the absence of an active protection interval, the competitor (aka computer) is set up to steal a point every so often. Participants are alerted to the fact that points are stolen by a visual cue: their usually black-colored total points counter enlarges and flickers in red and loses a point. Points can be stolen at any time unless a protection interval is active. It's important to note that protection intervals cannot be saved up for later times.
After learning about the game rules in the Millisecond PSAP game, participants get 'matched' with their competitors on the 'gaming platform'. Once 'matched', participants play the game for 25 minutes.
What it Measures
The Point Subtraction Aggression Paradigm (PSAP) measures (reactive) aggression.
Psychological domains
- Aggression: Behavior intended to harm another individual
- Emotion Regulation: A person's ability to control emotional responding to incoming stimuli
- Inhibitory Control/Anger Management: Ability to overwrite one's initial emotional reactivity to aversive punishment
Main Performance Metrics
- retaliationScore: Number of times participants choose option 'B'; main measure of (reactive) aggression
Psychiatric Conditions
The following patient groups have been tested with the PSAP
- Borderline Personality Disorder (BPD)
- Antisocial Personality Disorder (ASPD) & Psychopathy
- Substance Use & Dependency Patients
- Schizophrenia
An implementation of the Point Subtraction Aggression Paradigm as used in Cherek et al (1997)
References
Search Google Scholar for peer-reviewed, published research using the Inquisit Point Subtraction Aggression Paradigm (PSAP).
Cherek, D.R., Moeller, F.G., Schnapp, W., Dougherty, D.M. (1997). Studies of Violent and Nonviolent Male Parolees: I. Laboratory and Psychometric Measurements of Aggression. Biological Psychiatry, 41, 514-522.
Moeller, F.G., Dougherty, D.M., Lane, S.D., Steinberg, J.L., Cherek, D.R. (1998). Antisocial Personality Disorder and Alcohol-Induced Aggression. Alcoholism: Clinical and Experimental Research, 22, 1898-1902.
Cherek, D.R. & Lane, S.D. (1999). Laboratory and Psychometric Measurements of Impulsivity among Violent and Nonviolent Female Parolees. Biological Psychiatry, 46, 273-280.
Cherek, D.R., Lane, S.D., Dougherty, D.M., Moeller, F.G., & White, S. (2000). Laboratory and Questionnaire Measures of Aggression Among Female Parolees With Violent or Nonviolent Histories. Aggressive Behavior, 26, 291-307.
Golomb, B.A., Cortez-Perez, M., Jaworski, B.A., Mednick, S., & Dimsdale, J. (2007). Point Subtraction Aggression Paradigm: Validity of a Brief Schedule of Use. Violence and Victims, 22, 95-103.
Carré, J.M., Gilchrist, J.D., Morrissey, M.D., McCormick, C.M. (2010). Motivational and situational factors and the relationship between testosterone dynamics and human aggression during competition. Biological Psychology, 84, 346-353.