Finding nursing's own focus
The behavioral system model was developed by Dorothy Johnson (1919–1999), who studied nursing at Vanderbilt, earned a master's in public health at Harvard, and taught at UCLA for more than 25 years starting in 1949. As American nursing moved into universities in the 1950s, it faced a pointed question: if medicine deals with disease, what does nursing deal with? In her 1959 essay "A Philosophy of Nursing," Johnson first argued that nursing's focus is the person's behavior, not the disease.
She wove together Nightingale's attention to the patient's response, Talcott Parsons's social systems theory, behavioral science, and general systems theory, presenting the model formally in a 1968 lecture at Vanderbilt. The fullest written version appeared in 1980 in Riehl and Roy's Conceptual Models for Nursing Practice. In the meantime, her UCLA student Callista Roy built the adaptation model under her guidance, and Johnson's systems thinking rippled through later models, including the Neuman systems model.
Seven subsystems
Johnson grouped behavior by purpose into seven subsystems: attachment–affiliative (belonging and social bonds), dependency (seeking help and attention), ingestive (taking in food), eliminative (getting rid of waste), sexual (procreation and sexual identity), aggressive–protective (defending self and others), and achievement (mastering the environment). Later scholar Judy Grubbs added a restorative subsystem for rest and recovery, making eight.
Each subsystem has four structural elements: the goal or drive behind the behavior, the set (a predisposition to act a certain way), the choice (the range of options), and the observable behavior itself. To function, each subsystem needs three functional requirements from the environment: protection, nurturance (resources for growth), and stimulation.
Nursing as an external regulatory force
For Johnson, health is a balanced, stable behavioral system. When illness or a changing environment throws the subsystems out of balance, nursing steps in as an external regulatory force, supplying or limiting protection, nurturance, and stimulation so the system can regain equilibrium. Take a teenager on chemotherapy whose appetite has collapsed: the nurse looks beyond the ingestive subsystem to the attachment–affiliative strain of being cut off from friends and the achievement frustration of falling behind in school, then plans small frequent meals (nurturance), video calls with friends (stimulation), and infection-prevention teaching (protection).
Strengths and limitations
By naming behavior as nursing's focus, Johnson carved out territory distinct from medicine, and her model works well as a structured assessment tool, especially in pediatric and psychiatric nursing. Historically, it matters as a "theory of theories" that trained the next generation, Roy included. On the downside, relationships among concepts and ways to measure the subsystems are underdeveloped, the individual focus limits use with families and communities, and because Johnson published relatively little, interpretations vary.
See also
Nursing theory · Roy adaptation model · Neuman systems model · General systems theory · Henderson's 14 basic needs
FAQ
- Seven subsystems or eight?
- Johnson's original model has seven. Some textbooks teach eight, adding the restorative subsystem proposed by Grubbs and others.
- How is it related to Roy's model?
- Roy developed her adaptation model as Johnson's student at UCLA. Both see the person as a system, but Roy centers on adaptation and Johnson on behavioral balance.
Sources reviewed: 2026-10-26
References
- Johnson, D. E. (1980). The behavioral system model for nursing. In J. P. Riehl & C. Roy (Eds.), Conceptual Models for Nursing Practice (2nd ed., pp. 207–216). New York: Appleton-Century-Crofts.
- Johnson, D. E. (1959). A philosophy of nursing. Nursing Outlook, 7(4), 198–200.
- Grubbs, J. (1980). An interpretation of the Johnson behavioral system model for nursing practice. In J. P. Riehl & C. Roy (Eds.), Conceptual Models for Nursing Practice (2nd ed.). Appleton-Century-Crofts.
- Alligood, M. R. (Ed.). (2021). Nursing Theorists and Their Work (10th ed.). Elsevier.