A little while ago, I made mention that I had noticed the weapons
effect, which I had always considered to be a phenomenon, referred to as
a theory. In a way I found it amusing. In another way, I think the
argument in favor of a weapons effect theory does have some merit. A
good theoretical model would at minimum offer an explanation regarding a
phenomenon and generate testable hypotheses. In the case of the weapons
effect, it would be a relatively narrow theory. Then again, so too was
frustration-aggression theory (itself an outgrowth of what was merely a
hypothesis).
We know the origins of what we could call weapons
effect theory. We look no further than Berkowitz and LePage (1967). As
the details of that initial experiment are detailed elsewhere, I will
simply state that Berkowitz and LePage (1967) appeared to demonstrate
that under conditions of high provocation, individuals experiencing
short-term exposure to weapons showed higher levels of aggression
(measured in number of electric shocks given) than those who had not
been exposed to weapons. It goes without saying that the claim was
highly controversial at the time, and that there were critics who could
not replicate the original finding. That story has been told many times
(including by me - see Benjamin 2019 or Benjamin, 2021), and bears no
repeating here. What probably matters most is that a meta-analysis by
Carlson, Marcus-Newhall, and Miller (1990) was supposed to have settled
the matter. Short-term exposure to weapons under conditions of high
provocation or frustration seemed to lead to a noticeably higher level
of aggression than any other condition. Armed with Fail-Safe N as a
means of assessing publication bias, Carlson et al (1990) concluded that
the case was effectively open and shut. The weapons effect was viable,
and it was time to move on. After that, social psychologists and some
fellow travelers looked toward underlying processes responsible for this
purported effect. That's where theory comes in.
Although the Anderson, Benjamin, and Bartholow (1998) paper referenced
Anderson's then General Affective Aggression Model (which would be later
abbreviated to General Aggression Model or GAM), I think it is safe to
say that what we we actually did was to articulate a distinctive weapons
effect theoretical model. Among social cognition models, it is a
potentially "warm" theory in the sense that anger and arousal are
considered potential antecedents. However, anger (affect) and arousal
have never been adequately tested. Rather, testing of the model
primarily focuses on short-term exposure to weapons priming of
aggressive cognitions - think of these as behavioral scripts and schemas
that include all of our semantic and episodic memories and concepts of
aggression and violence as well as procedural memories of how to behave
aggressively or violently. These memories may be implicit or explicit.
Once aggressive cognitions have been primed, primary and secondary
threat appraisals are primed, increasing the likelihood that an
individual will be biased to perceive stimuli as more threatening than
they might have otherwise, along with appraisals of how to best respond.
Depending at what happens at the level of appraisal, an aggressive
behavioral response might be the end result. Although primarily focused
on the situational antecedents, the model keeps the door open to
individual differences that might serve as antecedents (including
personality traits and life experience). See the figure below. Note that
technically this figure is the property of Sage Publications (from
Anderson et al,, 1998), and if I am asked to take it down, I will do so:

It's a simple theory, really. One sees a weapon, which facilitates an
increase in accessibility of aggressive cognitions, setting up primary
and secondary threat appraisals, culminating in increase of aggression.
The potential for weapons to prime anger and increase physiological
arousal exist as well. It is a model that explains a body of results on a
phenomenon, and offers some potential hypothesis tests. So far, so
good. So, how well does the weapons effect theory hold up? Depending on
whom you read, the weapons effect theory is either sufficiently
established that we what we really need to do is to further explore
interactions of person variables and short-term exposure to weapons (an
endeavor that has barely been undertaken, and then only in a very
scattershot fashion), or the body of research suggests the theory is
enough of a nothingburger as to be swept into the dustbin of history.
When I finally published my meta-analysis (Benjamin, Kepes, &
Bushman, 2018), I think any astute reader would hone in on Table 2 and
realize that depending on how how publication bias is assessed, that
there is nothing to be concerned about (if one believes random-effects
trim-and-fill analyses) or quite serious (e.g., PET-PEESE). Most
concerning are studies examining aggressive behavioral outcomes. The
effect sizes are arguably negligible. Even when we look at the
intervening variables in the model that are the underlying processes
responsible for the presumed relationship between short-term weapon
exposure and aggression (accessibility to aggressive cognitions and
hostile appraisals) we have to keep in mind that the effects for these
outcome variables are often small. Establishing accessibility of
aggressive cognition is difficult, and numerous methods of measuring
accessibility of aggressive cognitions have been utilized with varying
degrees of success. Although much of the earlier cognitive priming
literature for the weapons effect relied on either reaction times to
aggressive versus non-aggressive words in lexical decision tasks or
pronunciation tasks, more contemporary studies appear to rely on
variations of a word completion task developed by Anderson - an
instrument whose validity has been recently questioned. I wonder how
many unpublished studies slipped through the cracks. Research on mostly
primary threat appraisal has been more of a success story. Much of that
work seems to build on research comparing phylogenitic and ontogenetic
threats, with weapons being an ontogenetic threat. When individuals are
shown arrays of objects with guns or knives embedded, studies appear to
find evidence that individuals respond more rapidly to those arrays that
have nothing but neutral objects. Effect sizes are small-to-moderate.
One must also consider the possibility that arrays including unexpected
objects could be just as effective in decreasing reaction times. So,
although the pattern of findings looks promising, it's probably far from
settled. But ultimately, for a cognitively based theory of the weapons
effect to work, there has to be some establishment that aggressive
behavioral outcomes are consistently positive. So far, that has not been
the case. However aggressive behavior has been operationally defined -
number of electric shocks, shock/noise blast levels, amount of hot sauce
doled out to a presumed victim, point subtraction, etc., the results
have been inconsistent. Some experiments appear successful, but many
others do not replicate - either directly or conceptually - the original
finding. Furthermore, it is not entirely clear that we are
measuring aggression with these operational definitions, nor can we
necessarily include intention to harm from the body of research thus
far. Furthermore, there has been a tendency for those who do find
positive effects to oversell their findings, tying their analyses to not
merely the mild forms of aggression that we might be measuring, but to
tie that work to acts of violence such as shootings. The theoretical
model is not one that was designed to address violence per se, which
means that even if we could hone in on consistently reliable findings,
we can only speak to a narrow range of possible aggressive behaviors in
everyday life, and even then with a good deal of caution and humility.
All that being said, we have a social cognitive model that states that
short term exposure to weapons can trigger an aggressive behavioral
response, to the extent that aggressive cognitions and hostile
appraisals are successfully primed. Without a solid body of evidence
pointing to an increase in aggressive behavior in this body of research,
the theory falls apart. Unless or until the behavioral outcome piece of
the theory is settled, it is a weak theory at best. If research
surfaces that debunks any priming effect of weapons on aggressive
cognitions, then the theory goes from weak to effectively moot. At that
point, why even discuss the matter further?
Left unanswered in the theoretical model is the role of arousal. My
impression is that early on, arousal was looked at as a nuisance
variable to be measured and ruled out. I know of one explicitly reported
arousal study, and it was a pilot study used to select stimulus
materials. As a "warm" theory, I've been a bit taken aback at the lack
of interest among those best positioned to examine arousal and affect to
actually take the time to do so and report their findings. Nor has the
moderating role of individual differences been adequately explored.
Aside from some one-offs, very little is known about the role of
personality or life events as a moderator of the relationship between
short-term exposure to weapons and aggressive behavioral outcomes.
Research
from the last decade has been discouraging. In the last two or three
years, we've seen published some ecological valid behavioral work that
was either adequately sampled, but showed a small effect size, or what
on the surface appeared to be a robust effect, but in which the sample
small enough that the statistical test was underpowered. Let's just say
that historically experiments testing hypotheses derived from this
theory rarely have samples of 15 or more in each cell, and even a sample
of 15 per cell is probably inadequate. More traditional experimental
research (i.e, in the lab) in recent years appears to suggest the
behavioral effect is minimal at best. For example Guo, Egan, and Zhang
(2016) found no main effect of weapons on aggressive behavior, and
instead used a subsample of individuals who scored as high in external
locus of control in order to craft a narrative for their findings.
That's just the published research. I am aware of unpublished behavioral
experiments (based on personal communication) that have found either a
null effect, or even a suppression effect. That should give any of us
who either have researched the weapons effect theory or who utilize this
theory as part of our pedagogy pause.
Bottom line? As a
theoretical model, I am very uncertain that the weapons effect theory is
on solid ground. If anything, I am likely to agree with those who would
argue that it is not on solid ground at all, and that it is a
theoretical model worth abandoning. There appear to be small to moderate
effects when it comes to weapons priming aggressive cognitions and
hostile threat appraisal. The effect on aggressive behavior appears
potentially negligible. I say that as someone whose professional
identity was in some significant sense tied to this particular theory. I
also say this as someone who has, in the past taught history of
psychology to undergraduates, and who has a keen interest in my area's
history. The conditions that made a link between short-term exposure to
weapons and the very mundane aggression we can observe in the lab are
ones in which there was both an increase in violent media consumption
(in which weapons were ubiquitous) and an increase in real life violence
(something Berkowitz goes into in a 1968 paper) seemed plausible. Since
that time, the concept of media violence and real life violence has
been effectively debunked. Whether or not a weapons effect theory holds
up in the sense that, say frustration-aggression appears to hold up is
questionable at best. I think a registered replication report of the
original Berkowitz and LePage (1967) would be wise, assuming it were
ethically and logistically doable, if for no other reason than to settle
the matter once and for all.