In this study, the authors explore the types of circumstances that would compel abystander to intervene and save a stranger in a violent confrontation.

Slater, M., Rovira, A., Southern, R., Swapp, D., Zhang, J. J., Campbell, C., & Levine, M.
(2013). Bystander responses to a violent incident in an immersive virtual
environment. PloS one, 8 (1), e52766.
In this study, the authors explore the types of circumstances that would compel a
bystander to intervene and save a stranger in a violent confrontation. It has been well-
established that bystanders are less likely to help a stranger when in a large group. Here, the
researchers sought to find out whether social identity plays a crucial role in the intention to
help strangers. To accomplish this, 40 male supporters of Arsenal Football Club were
enrolled for a two-factor between-groups experiment: in-group or outgroup (the victim being
an Arsenal supporter or not, respectively) and looked towards the participant or not when
seeking help during the incident. The types of response interventions were assessed based on
the number of physical and verbal interventions by the participant during the altercation.
Overall, according to the findings, participants’ physical intervention scores were higher in
the in-group setting than in the out-group setting. In addition, participants intervened more
when the victim was looking at them when seeking help in the in-group but not in the out-
group settings. Verbal interventions were highest in the outgroup setting; participants were
more likely to engage in a confrontational intervention when the victim shared a similar
social identity.
The study showed that participants were intervened more in the ingroup setting when
they believed that the victim was looking towards them for help. Conversely, the “look at”
and “victim looked” conditions did not seem to influence decisions on whether to render help
in the out-group setting. Although participants in both groups reported a strong desire to stop
the argument, and the same fear and anxiety, those in the ingroup setting expressed higher
levels of frustration and anger (40%) than those in the out-group setting (17%). In the

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outgroup setting, participants reported feeling sorry for the victim but did not express feeling
involved in the confrontation. The authors further demonstrated that psychological group
affiliation was a significant determinant in intervention behaviour. Therefore, the “one of us”
paradigm is critical in bystander decision-making. This finding could be further generalized
through other identities such as race, class, or members of distinct groups.
Changing Attitudes and Behaviour

Verplanken, B. & Roy, D. (2016). Empowering interventions to promote sustainable
lifestyles: Testing the habit discontinuity hypothesis in a field experiment. Journal of
Environmental Psychology, 45, 127-134
In this study, Verplanken and Roy explore the habit discontinuity hypothesis, which
states that the likelihood of successfully changing a habit is higher when there is a disruption
in the individual’s routine, such as a change in environment or life event. This hypothesis
suggests that breaking away from familiar patterns can make it easier to establish new habits.
To test this hypothesis, 800 participants were separated into two intervention groups: an
intervention promoting sustainable behaviours or no intervention. In the intervention group,
participants were given sustainable items and a newsletter targeting environmentally-
sensitive behaviours such as waste reduction, water conservation, saving gas and electricity
and reduced car usage. This group also participated in a Personal Interview intervention
where participants were talked through the purpose and goals of the intervention. The authors
controlled other behaviours such as perceived control, personal norms, intentions, and habit
strength. The findings affirmed that interventions were more effective among recently
relocated participants, projecting a ‘window” for effective behavioural alteration three
months after a major life change.
The authors measured 25 relevant behaviours over a period of one year, with
frequencies of performing these behaviours being rated on 5-point scales. Habit strength was

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also assessed using the Self-Report Habit Index on four behavioural domains relevant to the
intervention: producing less waste, reducing car use for short journeys, using less water, and
reducing gas and electricity use. Further, a multiple regression analysis was conducted to
measure variance and correlation. The results of the study showed that participants in the
intervention group (those who had relocated recently) reported more change over a 1-year
period than participants who had not relocated recently. These findings are in line with those
from several other studies suggesting that the best time to effect sustainable change is just
after a major life change. In this study, that major change was relocation.