The Model of Hierarchical Complexity (MHC) is, in its simplest form, a way of measuring and scoring the complexity of a behavior, placing people, animals, and even computer programs into a specific stage based on the complexity of those behaviors. Developed by Dr. Michael Commons and others since the 1980s, the MHC is rooted in mathematical principles and is able to quantify the previously qualitative characteristics of behavior.
Because the MHC is mathematical and quantitative, it can be used cross-culturally, across different species, and can even be used for computers. It allows us to treat behavior accurately and in all-or-nothing terms. These are important characteristics when studying human behavior, which is often difficult to define and report, and can help tremendously for animal and human studies. It also offers the opportunity to give more effective therapeutic treatments, measure the effectiveness of interventions, develop competitive and innovative organizations (particularly by aiding in the hiring process), reduce crime, and do so much more.
It is perhaps easiest to describe the MHC in terms of a videogame. The fifteen orders in the MHC can be thought of as fifteen semi-unique levels, and as you advance in the game, your actions (behaviors) become more complex, with each level becoming more difficult than the one before it. In the first level, you may be asked to complete some task A, and once you have completed this task, you can move on to the second level. Level two would have you complete a task B more difficult than task A, but in order to beat the level, you still must be skilled in task A and be able to use information from level one to successfully beat level two. Level three would then continue with this pattern, drawing on the information and skills taught in the first two levels while adding additional actions, which would continue throughout all fifteen levels. Just like in a videogame, you cannot go on to level six before having completed levels one through five in order.
Each task outlined by the MHC contains a set of subtasks. When subtasks are carried out in the required order, the task can be considered completed, and tasks can only be completed in an all-or-nothing manner—a task cannot be partially complete. Continuing with the analogy of our fifteen-level videogame, we might imagine some similar scenario. A character has asked you to retrieve the keyboard he loaned to his neighbor, and in exchange he will give you a portion of the money needed for you to buy a necessary upgrade. You go to his neighbor’s house, but he has loaned out the keyboard to his friend in exchange for a trumpet. You take the trumpet to the neighbor’s friend in order to get the keyboard back. When you return it to the original character, you receive the money, completing the task. The key is that the trumpet must be first returned in order to return the keyboard; the ordering of tasks is not arbitrary. When you have completed enough tasks, you can buy the upgrade and move on to the next level. The series of tasks completed in this order define the many subtasks of each task outlined by the MHC.
There are, of course, other stage concepts in the field of psychology. The stages of development defined by Piaget and the stages of moral development defined by Kohlberg help show us the importance of defining stages, especially in human progression. The MHC has built on research of these earlier stage theories and improved and expanded them. Analyzing these stages allow us to more accurately rate behavior for research, be it psychological or medicinal, and it allows us to better understand living creatures and even quickly developing AI technology.