TRIZ and Psychological Inertia 
Yunmei Hong, Hyman Duan 

Overcoming psychological inertia which blocks the invention ideating is one of main functions of TRIZ. Although all TRIZ people accept the validity of the statement, there is insufficient systematic analysis about it.
Authors believe that the majority parts of TRIZ aim at the effect of psychological inertia. The inertia in TRIZ is not the common psychological inertia in everyday life, but the ones modern engineers encounter in their invention activities. Authors believe it is essential to systematically analyze the contents of psychological inertia, understand how various formats of representing psychological inertia affects the innovation activity, investigate the history background behind the thinking, and focus on the effect caused by various thinking habits. TRIZ provides several methods to overcome psychological inertia. But it is reflection that is the most important but not drawing much attention from TRIZ people.
In this paper, authors elaborate the relationship between TRIZ and psychological inertia, propose using reflection and introspection to overcome psychological inertia and improve the consciousness of applying TRIZ.
1 Introduction
Mental set is a preparing state for an activity or tendency, usually unconscious. It is derived from an individual’s experience, related to certain type of objects. Mental set represents itself in various aspects, such as: set of movement is the preparing state of an individual engaged in a kind of sports; attention set is the status of an observer ready for receiving certain information; perceptual set is the tendency of an individual when apperceiving objects according to anticipation and background knowledge instead of the physical reality; the set during problem resolving process is the effect of mental set to thinking activity.
Mental set has advantages and disadvantages. On one hand, mental set enhances an individual’s perception and thinking ability when the object or situation of a psychological activity remains same. Problems can be easily solved by following convention methods. On the other hand, when the object or situation of a psychological activity look very similar to the ones from individual’s past experience but actually substantially different, a potential mental set will hinder the adaptivity of perception and thinking process, further be a barrier of innovation.
Psychological Inertia (PI) is a concept used in TRIZ. It is the predilection towards conventional ways to analyze and solve problem [5]. It shares great similarity to the set during problem solving process defined in psychology. We discuss PI in this paper.
Contents of a thinking process related to PI are mainly about solving problems. Invention is to solve problem, especially technical problem, with creativity. As an innovation methodology, TRIZ aims at overcoming PI.
TRIZ provides heuristics instead of rigid formula. The heuristic first comes from eliminating PI. With the fact that problem situation on which the methods for invention and creativity technical thinking act are always changing, it is obvious that PI is a barrier to personal creativity. The heuristic from TRIZ emphasize overcoming PI.
In reality, the importance of the effect that PI does to TRIZ is not fully aware. Human factor plays big role in many aspects during TRIZ problem solving process (Figure 1). It is very likely that human activities in each step during the process are affected by PI. It has to be individual himself/herself to overcome his/her PI. Therefore, from the perspective of understanding and overcoming PI, human factor should be paid more attention. 
Figure 1 TRIZ problem solving process [8]
Equipped with science and technologies, modern engineers can reduce the randomicity from trial-and-error during an inventing process. But, technologies are quickly developing, incorrect and incomplete understanding to science is unavoidable, which contributes to the accumulation of PI. We call it “modern engineer’s PI”. It commonly exists in engineer’s thinking activity and is to be overcome while applying TRIZ.
A general inventive thinking process consists such procedures, initial fuzzy situation, problem arising, problem selection, problem statement, problem solving direction selection, concept generation, concept synthesize and concept evaluation. Among these procedures, TRIZ’s heuristic provides most valuable guidance to problem arising, problem statement, problem solving direction selection and concept generation, which are very vulnerable to PI and might hinder the invention thinking if not being taken care of. We will elaborate how heuristics mirrors PI in section 3.
2 Basic Concepts of PI
Before delving into the discussion of PI, we clarify some concepts related to PI:
² Contents of PI
Contents of PI can be classified by the content of thinking itself, such as “ functional fixedness”, “method fixedness”, “project fixedness” and “pure-technology-centered”.
² Sources of PI
Sources of PI are the existing thinking activity that helps to produce PI, such as personal knowledge, experience, and specialized work.
² Carrier or psychological representation of PI
Carrier of PI is the format representing the thinking activities in a person’s mind, such as terminology, image, and symbol.
² Methods to overcome PI
Methods to overcome the PI are the methodology that is used to overcome or eliminate PI.
We will discuss these concepts further in below sections.
3 Content of PI
The contents of PI can be abstracted from classical TRIZ works [9, 10] and listed below with several examples:
² Get used to looking at and use only common characteristics of an object but not identifying and utilizing all available resources.
Therefore, people get used to pay attention to the common functions which may not be identical to the main functions of the object and they tend to think about the common functions as main ones. This situation is similar to “functional fixedness” discussed in psychology and is very common during inventive problem solving.
² Try solving a new problem using the method that resolved a seemly similar, but indeed different, problem.
This is kind of method set discussed in psychology. When a person successfully solves some problems using one method, he or she tends to use the same method to solve other problems, and even derives more complex solution with great similarity to the first method used. But it is likely the resolution and its derivatives are not suitable for other problems. We can call it “method fixedness”.
² Strong psychological barrier appears when there is ne