Institutional Aggression: Importation
The Importation Model (Irwin and Cressey)
This explanation focuses on the personality characteristics that prison inmates take into the prison with them. For example inmates with values, attitudes, experiences, and social norms that tend towards violent behaviour towards other people will be more likely to engage in interpersonal violence than inmates with less violent personalities and experiences. Often it is younger inmates that tend to behave violently as they are more likely to find it harder to adjust to prison life, and may therefore engage in more conflicts with others, and are more likely to view aggression as an appropriate way of dealing with conflict. The importation model argues therefore that it is not situational pressures of prison that causes aggression, but rather the personalities of the individuals within it.

AO2 evaluation
There is research evidence to support the model. Adams found that in American prisons, black inmates were more likely to be associates with violent acts than white inmates. The argument for this is that black prisoners tended to come from poorer backgrounds with higher rates of crime, and so imported their cultural norms into the prison.

Harer and Steffensmeier found that in US prisons, black inmates were significantly more aggressive than white inmates, but that white inmates were significantly more likely to engage in alcohol and drug taking than black inmates. They argued that this behaviour reflected the cultural norms that black and white societies hold outside prison, and so the behaviours had been imported into the prison.

Keller and Wang found that prison violence is more likely to occur in facilities with higher-security inmates than those with lower security inmates, again supporting the idea that the inmates had brought violent behaviour into the institution with them.

Poole and Regoli collected data from four different young offenders’ institutions and found that pre-conviction violence was a greater predictor of institutional aggression than overcrowding and other stresses within the institution. This is an indirect support of the importation model over the deprivation model.

DeLisi et al found a slight positive correlation between gang membership and aggression in prison, suggesting that aggression factors from before entering prison influence aggression in prison. However, the relationship may not be casual as there may be intervening variables such as socioeconomic status or ethnicity.