1. Social ecological model
Socioecological models were developed to further the understanding of the dynamic
interrelations among various personal and environmental factors.
Introduced as a conceptual model in the 1970s, formalized as a theory in the 1980s, and
continually revised by Bronfenbrenner until his death in 2005, Urie Bronfenbrenner’s Ecological
Framework for Human Development applies socioecological models to human development. In
his initial theory, Bronfenbrenner postulated that in order to understand human development, the
entire ecological system in which growth occurs needs to be taken into account. In subsequent
revisions, Bronfenbrenner acknowledged the relevance of biological and genetic aspects of the
person in human development.
Bronfenbrenner’s ecological framework for human
development
Bronfenbrenner’s ecological framework for human
development was first introduced in the 1970s as a
conceptual model and became a theoretical model in the
1980s. Two distinct phases of the theory can be identified.
Bronfenbrenner stated that “it is useful to distinguish two
periods: the first ending with the publication of the Ecology
of Human Development (1979), and the second
characterized by a series of papers that called the original model into question.”
Ecological systems theory
In his original theory, Bronfenbrenner postulated that in order to understand human
development, the entire ecological system in which growth occurs needs to be taken into
account. This system is composed of five socially organized subsystems that support and guide
human development. Each system depends on the contextual nature of the person’s life and
offers an ever-growing diversity of options and sources of growth. Furthermore, within and
between each system are bi-directional influences. These bi-directional influences imply that
relationships have impact in two directions, both away from the individual and towards the
individual.
Microsystem
The microsystem is the layer closest to the child and contains the structures with which
the child has direct contact. The microsystem encompasses the relationships and interactions a
child has with his or her immediate surroundings such as family, school, neighborhood, or
childcare environments. At the microsystem level, bi-directional influences are strongest and

2. have the greatest impact on the child. However, interactions at outer levels can still impact the
inner structures. This core environment stands as the child’s venue for initially learning about the
world. As the child’s most intimate learning setting, it offers him or her reference point for the
world. The microsystem may provide the nurturing centerpiece for the child or become a
haunting set of memories.
Mesosystem
The mesosystem moves us beyond the dyad or two-party relation. Mesosystems connect
two or more systems in which child, parent and family live. Mesosystems provide the connection
between the structures of the child’s microsystem. For example, the connection between the
child’s teacher and his parents, between his church and his neighborhood, each represent
mesosystems.
Exosystem
The exosystem defines the larger social system in which the child does not directly
function. The structures in this layer impact the child’s development by interacting with some
structure in his/her microsystem. Parent workplace schedules or community-based family
resources are examples. The child may not be directly involved at this level, but he does feel the
positive or negative force involved with the interaction with his own system. The main
exosystems that indirectly influence youth through their family include: school and peers,
parents' workplace, family social networks and neighborhood community contexts, local politics
and industry.
Macrosystem
The macrosystem is composed of cultural values, customs, and laws. It refers to the
overall patterns of ideology and organization that characterize a given society or social group.
Macrosystems can be used to describe the cultural or social context of various societal groups
such as social classes, ethnic groups, or religious affiliates. This layer is the outermost layer in
the child’s environment. The effects of larger principles defined by the macrosystem have a
cascading influence throughout the interactions of all other layers. The macrosystem influences
what, how, when and where we carry out our relations.
Chronosystem
The chronosystem encompasses the dimension of time as it relates to a child’s
environment. Elements within this system can be either external, such as the timing of a parent’s
death, or internal, such as the physiological changes that occur with the aging of a child. Family
dynamics need to be framed in the historical context as they occur within each system.
Reference: http://en.wikipedia.org/wiki/Social_ecological_model

3. The Social-Ecological Model: A
Framework for Prevention
The ultimate goal is to stop violence before it begins. Prevention requires understanding
the factors that influence violence. CDC uses
a four-level social-ecological model to better
understand violence and the effect of
potential prevention strategies (Dahlberg &
Krug 2002). This model considers the
complex interplay between individual, relationship, community, and societal factors. It allows us
to address the factors that put people at risk for experiencing or perpetrating violence.
Individual
The first level identifies biological and personal history factors that increase the
likelihood of becoming a victim or perpetrator of violence. Some of these factors are age,
education, income, substance use, or history of abuse.
Relationship
The second level examines close relationships that may increase the risk of experiencing
violence as a victim or perpetrator. A person's closest social circle-peers, partners and family
members-influences their behavior and contributes to their range of experience.
Community
The third level explores the settings, such as schools, workplaces, and neighborhoods, in
which social relationships occur and seeks to identify the characteristics of these settings that are
associated with becoming victims or perpetrators of violence.
Societal
The fourth level looks at the broad societal factors that help create a climate in which violence is
encouraged or inhibited. These factors include social and cultural norms. Other large societal
factors include the health, economic, educational and social policies that help to maintain
economic or social inequalities between groups in society.
Reference: Dahlberg LL, Krug EG. Violence-a global public health problem. In: Krug E, Dahlberg LL, Mercy
JA, Zwi AB, Lozano R, eds. World Report on Violence and Health. Geneva, Switzerland: World Health
Organization; 2002:1–56.