"Lab-based measure of aggression" are to "real aggression" what college students are to all humans

Aggression is a common feature of social interactions.  Therefore, it is important for social scientists to develop a well-rounded understanding of this phenomenon.  One valuable approach to understanding aggression is laboratory-based research, which requires researchers to have usable and valid methods for measuring aggression in laboratory settings.  However, behaviors that are clearly aggressive, such as one person forcefully striking another person with a weapon, are fraught with ethical and safety considerations for both participants and researchers.  Such behaviors are, therefore, not a viable option for displayed aggression within lab-based research.  For these reasons, aggression researchers have developed a repertoire of tasks that purportedly measure aggression, are believed to be safe for participants and researchers, and are ethically-palatable.  I collectively refer to these tasks as “lab-based aggression paradigms.”  The major concern herein is whether the behaviors exhibited within lab-based measures of aggression are representative of "real" aggression. 

A common definition of aggression is “a behavior done with the intent to harm an individual who is motivated to avoid receiving that behavior” (Baron & Richardson, 1994, p. 7). If one adheres to this definition, a behavior is considered aggressive when both (a) a harmful behavior has occurred and (b) the behavior was done (i) with intent to harm the target and (ii) the belief the target wanted to avoid receiving the behavior. A strength of this definition is the clear demarcation between harmful behaviors that are not aggressive (i.e., a dentist who causes pain in the process of pulling the tooth of a patient; inflicting consensual pain for sexual pleasure, etc.) and harmful behaviors that are aggressive (i.e., punching another person out of anger; yelling at another person and causing a fear response, etc.). 

As hinted to above, the degree of "harm" that is permissible within lab-based settings is very mild. In fact, the lower bound of harmfulness at which behaviors become unambiguously aggressive is likely the upper bound of harmfulness that is permissible within laboratory settings.  

Extending Baron and Richardson’s (1994) definition, Parrot and Giancola (2007) proposed a taxonomy of how such aggressive behaviors may manifest. Within their taxonomy, aggressive behaviors vary along the orthogonal dimensions of direct versus indirect expressions and active versus passive expressions. For example, a physical fight would be considered a direct and active form of physical aggression whereas not correcting knowingly-false gossip would be considered an indirect and passive form of verbal aggression (to the extent the individual believes their inaction will indirectly harm a target individual). Because Parrot and Giancola strongly adhere to the definition of aggression proposed by Baron and Richardson, each of these forms of aggression are still required to meet the criteria described in the previous paragraph. The purported usefulness of this taxonomy is that factors that incite one form of aggression may not incite other forms of aggression. Thus, Parrot and Giancola assert that using their taxonomy to classify the different behavioral manifestations of aggression, and which antecedents causes those different behavioral manifestations, will lead to a nuanced understanding of the causes and forms of aggression.

The first dimension of Parrot and Giancola’s (2007) taxonomy is the direct versus indirect nature of the aggressive behavior. In describing the distinction between direct and indirect aggression, Parrot and Giancola state that direct aggression involves “face-to-face interactions in which the perpetrator is easily identifiable by the victim. In contrast, indirect aggression is delivered more circuitously, and the perpetrator is able to remain unidentified and thereby avoid accusation, direct confrontation, and/or counterattack from the target” (p. 287). However, several lab-based aggression paradigms seemingly have features of both direct and indirect forms of aggression. Many of these paradigms involve contrived interactions where participants communicate with a generic “other participant,” for example, via computer or by evaluating one another’s essays. These contrived interactions are not really face-to-face and they are not really anonymous. So the behaviors within lab-based aggression paradigms are not cleanly classified as being either direct or indirect within Parrot and Giancola’s taxonomy. 

Similarly, participants’ behaviors exhibited within lab-based aggression paradigms are often not “directly” transmitted to the recipient of those behaviors. For example, participants do not make physical contact with their interaction partner at any point within these paradigms. The consequences of participants’ behaviors are often transmitted to the recipient via the ostensible features of the study in which they are participating. For example, in one lab-based aggression paradigm, participants’ harmful behavior is selecting how long another participant must submerge their hand in ice water (Pederson, Vasquez, Bartholow, Grosvenor, & Truong, 2014). Therefore, participants must believe (a) they can harm the recipient by varying how long they tell the experimenter to have the recipient hold their hand in ice water, (b) that a longer period of time causes more harm, and (c) the experimenter will successfully execute the harmful behavior at a later point in time.

Collectively then, it is questionable whether behaviors within lab-based aggression paradigms are considered “direct.” Nevertheless, it is clear that these behaviors do not include face-to-face aggression or physical aggression that includes direct physical contact. And the time of many of the behaviors within lab-based aggression paradigms are asynchronous with the (ostensible) delivery of harm to the recipient.

The second dimension of Parrot and Giancola’s (2007) taxonomy is the active versus passive nature of the behavior. Active aggression involves an individual actively engaging in a behavior that harms the recipient. In contrast, passive aggression is characterized by participants’ lack of action that is believed to cause harm to the recipient. All of the major lab-based aggression paradigms involve behaviors that are considered active.

In summary, within lab-based aggression paradigms, the harmfulness of the behaviors is on the extreme low end of the range of possible harmfulness, participants may believe their behaviors will only cause mild amounts of harm, participants may believe the recipient may only be mildly motivated to avoid the behaviors, and the form of participants’ behaviors may only cover a limited amount of the conceptual space of possible forms of aggression. Collectively, the behaviors exhibited in lab-based aggression paradigms seem to be limited and unrepresentative of the multi-faceted nature of aggression.

Is this potential un-representativeness a problem? On the one hand, the relationship between the behaviors within lab-based measures of aggression and "real" aggressive behaviors is like the relationship between a convenience sample of college students and "all humans."  The former is not a representative sample of the latter, therefore, the generalizability from the former to the latter is potentially biased. On the other hand, to the extent that the behaviors exhibited within lab-based aggression paradigms are valid instances of very mild and specific forms of aggression, lab-based research has a valuable place within a robust science of aggressive behaviors.