presence of weapons in the study room in combination with a subject that was not angered at the study onset, inhibited the number of shocks administered. Also, when researchers told the subjects that the confederate was a policeman, the presence of weapons in the study room in combination with a subject that was angered at the study onset, inhibited the amount of shocks the subject administered. A 1971 study by Page and Scheidt also found that individual differences played a major role in whether or not the weapons effect would be found in a study. Individuals who were more sophisticated presented different data than less sophisticated individuals, or those who were experiencing evaluation apprehension. They also concluded that any weapons effect that was demonstrated could not be generalized outside of a laboratory setting. Schmidt and Schmidt heavily criticized Berkowitz's theory of weapons as aggression-eliciting stimuli in their article Weapons as Aggression-Eliciting Stimuli: A Critical Inspection of Experimental Results. The authors examined the original weapons effect study and subsequent replications and failed replications, concluding that there was no experimental evidence of a cue-elicited weapons-effect on aggressive behavior. Instead, the authors attribute the occasional observed weapons effect to being a result of operant conditioning. Reverse weapons effect In 1991, Gary Kleck and Karen McElrath obtained archival data from 1979-1985 National Crime Surveys and the 1982 Supplementary Homicide Reports. The researchers wanted to examine the impact of firearms and other deadly weapons on: (1) the probability that threatening situations escalated to a physical attack, (2) the probability that injuries resulted from a physical attack, and (3) the probability that death resulted from a physical attack. Results were not consistent with the weapons effect. 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. In the case where there was a physical attack and the presence of a weapon, there was also less probability of injury. Yet, in the case where there was a physical attack, a weapon present, and an injury, there was an increased probability of death. Overall, this data suggests that the weapons effect (if there is indeed a weapons effect) is more nuanced than previously portrayed. Further, that the presence of guns may have had an inhibitory effect on physical violence . Kleck continued with this line of research, and in 2001 published another