Richard Polsky (1994) examined whether aggression in dogs can be elicited through the use of electronic pet containment systems. He collected data relating to incidents where dogs that were trained, or in the process of being trained, with an electronic pet containment system and had shown aggression towards people. Polsky concluded that due to the lack of prior development, the nature and intensity and context of the attacks, the incidents recorded could quite plausibly have involved shock-induced aggression.