This effect was first described by Leonard Berkowitz and Anthony LePage in 1967 in their paper "Weapons as Aggressions-Eliciting Stimuli" in the Journal of Personality and Social Psychology.
The original study design by Berkowitz and LePage is as follows: The researchers recruited 100 male university students for one in-laboratory session.
In 1975, Ann Frodi made an attempt to replicate the original weapons effect study cross-culturally in a Swedish population.
[4] Frodi used a very similar research study design; with a 100 male high school students either heavily angered or not by whom they thought was a peer.
In 1993, Arthur Kellermann and colleagues obtained data from police and medical examination records on risk factors in the home of occurring homicides.
Information on control subjects (matched to be the same as homicide victims on sex, race, age range, and neighborhood) was also obtained.
Besides inspiring a number of replications and extensions, the weapons effect and Berkowitz and LePage’s original study has received major criticism.
In 1991, Gary Kleck and Karen McElrath obtained archival data from 1979-1985 National Crime Surveys and the 1982 Supplementary Homicide Reports.
[12] Instead, the researchers found that the presence of all types of deadly weapons was strongly associated with threatening situations that did escalate to a physical attack.
[13] In his discussion, he bid scholars to question the causal effect of the presence of weapons in the scene on the incidence of homicide.
For example, in a book chapter from Psychology and Social Policy, author Charles Turner proposes that policy recommendations aiming to minimize criminal violence need to take in account that the aggressive meaning people attach to firearms, in addition to the availability of firearms, has an important role in criminal violence.
Nevertheless, with the mixed results and conclusions from weapons effect studies, it is not clear if this line of research will extend into support for or against gun control legislation.
Because of the nature of the weapons effect, it is impossible to directly test the original hypothesis in a real-world setting.
While the attempts at replicating or even finding a weapons effect may be performed flawlessly, that does not necessarily mean that the results of these studies is applicable in the real world.
It is important to note that an effect may have been found in many of these studies, but further research is necessary to determine the validity and replicability of these results.