During the 20th century, research in social psychology has been mainly motivated by the predictability of behavior based on mediating processes. Therefore, much of the scientific production of the last century have tried to identify, isolate, describe, and explain concepts related to thought and action (Montero 1994).

Social psychology showed curiosity and concern for the inaction of human groups in the face of emergent events, such as what happened in 1964 with CSG, a 28-year-old girl who was the victim of an assault with fatal consequences after not receiving help in time. Thirty-eight neighbors witnessed the event, but only one person called the police when the aggressor left the place (Gangsberg 1964). Although the eventuality does not show the number of witnesses or their degree of exposure to the event, various authors focus on a new conceptualization of group behavior (Manning et al. 2007). Under this premise, a bystander is a person present in each scenario who possesses the power to assume or avoid responsibility for its action.

As a prelude to the 1970s, the social psychologists Bibb Latané and John Darley promoted the first experimental study on the bystander, regarding his inhibition of action or transfer of responsibility (Levine 2012), based on behavioral predictability associated with the subject’s attitude, as an effect of the adjustment in his subjective perception of the norms of “pass” and “subjective control” and even his “value-expectation” belief scheme (Ajzen 1991). The experiments of Darley and Latané (Darley and Latane 1968) describe and explain the behavior of the spectator, who, regardless of his personality type, can imitate or influence the behaviors of others, assuming a proactive, apathetic, alienated, or anomic attitude. For this purpose, they posed emergent cases in experimental conditions, proving that the greater the presence of bystanders, the less supportive or helpful intervention was in the experimental subjects (Myers 1983). From this experience, the five moments in the bystander’s prosocial intervention are: (a) identifying the situation; (b) perceiving the risk in potential victims; (c) assuming the responsibility to intervene; (d) deciding to act; and (e) acting (Latané and Darley 1968, 1970). Burn (2008) applied this model to sexual and gender-based violence from the bystander perspective, identifying the five inhibitory barriers to prosocial action. These barriers involve the diffusion of responsibility (Levine 2012) and the determination of the victim (as potential or actual) in terms of their observable characteristics of appearance and behavior (Burn 2008). In this sense, the importance of understanding the behavior of the university spectator in relation to the approach of dating violence in their peer group is highlighted (Cusano et al. 2020).

According to the World Health Organization (WHO), gender-based violence constitutes a human rights abuse and a public health problem of epidemic proportions (WHO 2013), with a need for urgent action, as indicated in the World Report on Violence and Health of the Pan American Health Organization (PAHO) (Pan American Health Organization 2002). Data from 21 US universities surveyed in 2015 indicate that 1 in 5 female students and 1 in 20 male students experienced sexual assault during their formative years (Association of American Universities 2015). In the following four years, despite efforts to implement preventive programs and increased resources to identify this problem among students, the prevalence of sexual assault cases remained stable, and the rate of sexual assault persisted (Association of American Universities 2019; Jozkowski 2015). Therefore, the university population requires psychoeducation on sexual consent based on sociocultural factors (Ortiz and Shafer 2018).

Sexual violence prevention programs on college campuses generally address the establishment of limits on sexual consent for women (Berkowitz 2002; Davis 2000; Fabiano et al. 2003). They also include psychoeducational proposals for developing positive and proactive attitudes in the male population (Flood 2006; Gibson 2014). However, recent publications (Chabot et al. 2016; Deitch-Stackhouse et al. 2015) reflect that bystander intervention overcomes the dualistic view of sexual assault prevention focused on the victim and the aggressor (Mennicke et al. 2018; Brown et al. 2014; Lemay et al. 2019; Palmer 2016) and focuses on eradicating environments tolerant of violence and sexual assault. This model involves the inclusion of community intervention strategies for the promotion of socio-normative changes (Banyard et al. 2003). The prosocial model of the bystander is included (Darley and Latane 1968; Banyard et al. 2014, 2007; Crooks et al. 2018), for their empowerment in the face of situations at risk of sexual violence. These interventions aim to teach the college student to recognize the warning signs of possible sexual assault and encourage them to intervene if they see a peer in distress (McMahon and Banyard 2011). Some of these experiences increased bystander prosocial behavior (Banyard et al. 2007; Coker et al. 2011), but others did not (Gidycz et al. 2011). Regardless of their results, short-duration, group-focused program formats are identified as having limited overall reach and impact (Salazar et al. 2019).

Prosocial behavior, a differential construct of altruism, is associated with normative judgments, social skills, and self-regulatory capacity (Caprara et al. 2005). It acquires vital importance due to its association with the sense of community, attention, and care of the group to which it belongs, especially when emergencies arise (Martí-Vilar et al. 2019). This sense of community promotes action to interrupt aggression or a situation of potential aggression, going against social norms that support sexual violence, and being an effective and supportive ally for survivors (Cares et al. 2014).

Nevertheless, most of the primary prevention research in this field comes from the North American context. A cross-national review of violence intervention and prevention programs (Ellsberg et al. 2015) revealed that more than 80% of the rigorous evaluations were conducted in six high-income countries, which account for 6% of the world’s total population.

In this topic, systematic reviews and meta-analyses of programs that address sexual violence among university students were identified. In this regard, Park and Kim (2022) analyzed the effect of programs to reduce the risk of intimate partner violence in 13 randomized controlled trials. In turn, Finnie et al. (2021) included 28 studies in their review, considering interventions in intimate partner violence based on the promotion of alternative behaviors to aggression and the creation of protective environments. Additionally, Evans et al. (2019) analyzed 11 intervention studies on university bystanders, diverse in duration, instrumentation, and educational strategy. Likewise, Mahoney et al. (2019) applied the Haddon Matrix to evaluate intervention programs against sexual aggression on university campuses, selecting 31 articles published between 2001 and 2017, including experimental and quasi-experimental design programs. Finally, Jouriles et al. (2018) analyzed 24 articles on bystander attitudes, beliefs, and behaviors, their effects, and sustainability.

It should be noted that, although the mentioned studies are systematic reviews on educational programs against gender violence, they present certain limitations and parameters: three articles include publications on primary preventive intervention in intimate partners and tertiary preventive intervention (towards the perpetrator victim dyad), not being exclusive on bystanders (Park and Kim 2022; Finnie et al. 2021); also the presentation of the assessment and analysis of their effects (Finnie et al. 2021; Evans et al. 2019); the selection of experimental design programs in randomized controlled groups (Park and Kim 2022; Mahoney et al. 2019); and finally, the analysis of descriptive studies and processes of promotional and preventive intervention in bystanders (Jouriles et al. 2018). The main contribution of the present review study is that each selected article is based on educational interventions in prosocial behavior applied to spectators (as the main target population), regardless of their scope, methodology, intervention strategy, or evaluation of their sustainability over time.