Although research on bystander intervention and informal social control of intimate partner violence (IPV) is increasingly common, empirical anomalies remain and experimental studies on population samples are rare. This study reports the effects of a new experimental approach to the study of informal social control of IPV by neighbors on a small population sample of 100 married men in Seoul, South Korea. We hypothesized that men randomly assigned to a high‐perceived informal social control condition would have lower self‐estimated likelihoods of IPV perpetration in response to a vignette. We also hypothesized that the effect of random assignment would be different for that portion of the sample that reported perpetration of family violence (IPV or child abuse). Compared to the nonperpetrating portion of the sample, perpetrators of family violence in the sample randomly assigned to the high perceived control condition experienced a significant drop in self‐estimated likelihood of IPV perpetration.

Although previous research has demonstrated larger households to be at higher risk of physical abuse and neglect of children, we argue that unilateral conceptualization of larger households as a risk factor is inappropriate. Application of resource dilution theory must capture the possibility that larger families may have more members with both the agency and will to intervene against child maltreatment. We hypothesized a negative interaction between household size and protective informal social control by family members in predicting abuse injuries and neglect. A three-stage probability proportional to size cluster sample representative of Novosibirsk, Russia, was collected from 306 cohabiting couples. One parent in each household was interviewed. A focal child was selected using most recent birthday. When responses limited to families with minor children (below age 18) were selected, 172 families remained in the data. Physical abuse and neglect were measured using the Conflict Tactics Scales (CTS). Protective informal social control by family members was measured using the Informal Social Control of Child Maltreatment (ISC_CM) Scale. Models were tested using random effects regression and logistic regression. Nearly 7% of focal children were injured in the last year, 10% were neglected. Consistent with previous research, protective informal social control was associated with lower odds of injury and fewer instances of neglect. The significant negative interaction between household size and protective control is consistent with the idea that larger households may be protective when adult family members intervene against maltreatment to protect children. Replication and further investigation of protective ISC_CM in Western populations is much needed. Future research should not conceptualize or measure household size as a unilateral risk factor.