The short-term mechanisms that Dr. Huesmann referenced include priming, mimicry, and excitation transfer (Huesmann, 1988). In priming, stimulating one part of the brain results in activation of related parts, and lowers the threshold for such activation to occur again when faced with the same or similar stimuli. Thus, being exposed to violence or an associated element causes a cascade of reactions in the brain, which is poised to process more quickly the next time it is exposed. If such a cascade results in a violent response, this same response might occur more readily in the future. Excitation transfer, Dr. Huesmann noted, is more subtle. Observation of violence increases emotional arousal, but how that is experienced depends on individual and contextual factors. However, Dr. Huesmann also noted that if such excitation is accompanied by provocation or other situation likely to result in anger, then the arousal experienced by observing violence is likely to include anger, thus heightening the excitatory response.

Mimicry and Imitation

Mimicry involves copying behavior of someone with whom one identifies. Children can learn from mimicry, so observing violence would provide examples for how others respond to specific events. Speaker Marco Iacoboni from the University of California, Los Angeles, further explored the process of mimicry. He described cells within the brain called mirror neurons, which fire both when performing certain actions and when observing others perform those same actions. In firing during observation, the brain is simulating the action as a learning mechanism. Dr. Iacoboni described such neurons in particular regions of the brain, most notably those related to motor functioning and vision and memory, as explored through emerging research. Thus, Dr. Iacoboni notes, mirror neurons fire when performing certain motor activities such as grasping a door knob, when watching another person grasp a doorknob so as to learn the action, and when recording the memory of the action. Such a process is useful in learning behavior and also in recognizing behavior immediately, without taxing the brain with complex neural processing. Dr. Iacoboni also noted that the ability of mirror neurons to mimic others’ behaviors is an important element in social bonding and empathy, as well as the flip side of socially detrimental behavior of aggression and violence. For further information on the research involving imitation and mirror neurons, see Part II.

LONG-TERM PROCESSES

In the long run, Dr. Huesmann noted, violence is transmitted because observation results in changes in the cognitive functioning of the brain relevant to cues in the social environment. Specifically, the brain responds



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