Organizational behavior is a modern approach to

Organizational behavior : Is a modern approach to management that attempts to
determinate the causes of human work behavior and to translate the results into
effective management techniques. Organizational behaviorists have borrowed an
assortment of theories and research techniques from all the behavioral sciences and
have applied them to people at work in modern organizations. The result is an
interdisciplinary field in which psychology predominates. Organizational behavior has
had a significant impact on modern management thought by helping to explain why
employees behave as they do.
Lessons from the behavioral approach : This approach makes it clear to present and
future management that people are the key to productivity. According to advocates of
the behavioral approach, technology, works rules and standards do not guarantee
good job performance. Instead, success depends on motivated and skilled individuals
who are committed to organizational objectives. This doctrine has been criticized as
vague and simplistic, they do not believe that good human relations will lead to better
job performance.
The Systems approach
A system is a collection of parts operating interdependently to achieve a common
purpose. System approach represents a market departure from the past, in fact, it
requires a completely different style of thinking.
The other approaches studied management by taking things apart (the whole is equal
to the sum of its parts), but systems approach study management by putting things
together and assume that the whole is greater than the sum of its parts.
Analytic thinking is outside-in thinking and synthetic thinking is inside-out.
Systems theorists recommend synthetic thinking because management is not
practiced in a vacuum. Managers affect and are in turn affected by many
organizational and environment variables. Systems thinking has an enormous
challenge  to identify all relevant parts of organizational activity and to discover how
they interact.
Chester I. Barnard’s Early Systems Perspective : He is a Fayol’s follower. He
characterized all organizations as cooperative systems  “A cooperative system is a
complex of physical, biological, personal and social components which are in a specific
systematic relationship by reason of the cooperation of two or more persons for at
least one defined end”. He believes that willingness to serve, common purpose and
communication are the principal elements in an organization. Without this 3 element,
the organization did not exit. He said that managers have to study organizations as a
whole.

General systems theory : Is an interdisciplinary area of study based on the assumption
that everything is part of a larger, interdependent arrangement. In order to
understand an organized whole, we must know the parts and the relations between
them.