Model of Hierarchical Complexity

The Model of Hierarchical Complexity, sometimes referred to as the MHC in educational psychology, is a framework used to explore and organize the patterns of human development. It is a theory used when working with behavioral development in particular.

The MHC functions to give rank or order to the developmental complexity of a certain behavior. It is the basis for other hierarchical theories of development, such as Piaget. It was originally developed by Michael Commons, an American behavioral scientist.

Contributors: Michael Commons (1939 — present)

Key Concepts

Task Analysis

MHC is based on a system of task analysis in which tasks are broken down into minute steps and then analyzed based on their complexity in relation to the individual’s development. [1] The task is initiated when the individual is presented with a stimulus, and their behavior(s) in reaction to that task are what are analyzed for their developmental complexity. For example, an infant presented with a bright-colored toy would not reach toward the object or even train their eyes in its direction, but an older baby further along in the development process would do so.

Stages of hierarchical complexity

0 — calculatory stage

Characterized by having solely the capacity for computation, this stage functions as the “control” of sorts as it can be used to describe the hierarchical complexity of computers.

1 — automatic stage

Individual can respond to one environmental stimulus at a time.

2 — sensory or motor stage

Individual can move their limbs and parts of their face and view things. They begin to react to conditioned stimuli and form responses with discrimination.

3 — circular-sensory-motor stage

Individual can reach for, touch, or grab things. In terms of speech, individual will babble and is beginning to grasp phonemes (word parts).

4 — sensory-motor stage

Individual responds to stimuli based on their established concept of it.

5 — nominal stage

Individual can use names for objects as well as make commands. They begin to identify relationships between the concepts they have established and can name those as well.

6 — sentential stage

Individual can imitate others and acquire words or sentences through imitation, as well as following a sequence of acts presented by others.

7 — preoperational stage

Individual practices early deductive reasoning, engages in imitation, and can follow and tell a story or sequence of events.

8 — primary stage

Individual begins to make simple logical reasoning with regard to rules and time, also begins to grasp simple arithmetic.

9 — concrete stage

Individual can engage more deeply with arithmetic problems, understand more about social and group relations, and establish relationships with others and self.

10 — abstract stage

Individual begins to understand variables such as stereotypes and logic skills become more formalized.

11 — formal stage

Individual can argue using linear logic, can solve problems with one unknown, such as in algebra.

12 — systematic stage

Individual can establish and understand systems and understands relationships and logic problems with more than one variable or unknown.

13 — metasystematic stage

Individual can form relationships between systems and understand similarities and differences.

14 — paradigmatic stage

Individual can fit these new “metasystems” to form larger-picture paradigms, as well as point out inconsistencies between the various metasystems.

15 — cross-paradigmatic stage

Individual can see relationship between multiple paradigms, such as “this perspective is like that perspective because they both incorporate…”

16 — meta-cross-paradigmatic or performative-recursive stage

Individual can reflect on the similarities and differences between paradigmatic relationships. For example, “these two perspectives are inter-related because…”

These stages are linked to an age or developmental milestone in an individual’s life in various stage models. Some stage-based theories even use the same names as the MHC’s 16 stages, though most do not encompass it in its entirety.


Some developmental psychologists feel that the MHC phases are overly precise. Their criticism is that the MHC goes into too much detail of the various complexities of task analysis, and that the phases are less significant beyond stage 12, the systematic stage.


  1. Commons, M. L. (2008). Introduction to the model of hierarchical complexity and its relationship to postformal action. World Futures, 64(5-7), 305-320.