The human action cycle is a psychological model which describes the steps human

Human

Humans are the only living species in the Homo genus...

s take when they interact with computer systems. The model was proposed by Donald A. Norman, a scholar in the discipline of human-computer interaction. The model can be used to help evaluate the efficiency of a user interface

User interface

The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

 (UI). Understanding the cycle requires an understanding of the user interface design principles of affordance

Affordance

An affordance is a quality of an object, or an environment, which allows an individual to perform an action. For example, a knob affords twisting, and perhaps pushing, while a cord affords pulling...

, feedback

Feedback

Feedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...

, visibility

Visibility

In meteorology, visibility is a measure of the distance at which an object or light can be clearly discerned. It is reported within surface weather observations and METAR code either in meters or statute miles, depending upon the country. Visibility affects all forms of traffic: roads, sailing...

 and tolerance

Physiological tolerance

Physiological tolerance or drug tolerance is commonly encountered in pharmacology, when a subject's reaction to a drug is reduced at a later time even though the dose or concentration at the effect site is the same. This means that larger doses are required to achieve the same effect...

.

The human action cycle describes how humans may form goals and then develop a series of steps required to achieve that goal, using the computer system. The user then executes the steps, thus the model includes both cognitive activities and physical activities.

The three stages of the human action cycle

The model is divided into three stages of seven steps

Seven stages of action

Seven stages of action is a term coined by the usability consultant Donald Norman.He explains this phrase in chapter two of his book The Design of Everyday Things, in the context of explaining the psychology of a person behind the task performed by him or her.- History :The history behind the...

 in total, and is (approximately) as follows:

Execution stage

• 2. Translation of goals into a set of unordered tasks required to achieve goals.

• 3. Sequencing the tasks to create the action sequence.

• 4. Executing the action sequence.

Evaluation stage

• 5. Perceiving the results after having executed the action sequence.

• 6. Interpreting the actual outcomes based on the expected outcomes.

• 7. Comparing what happened with what the user wished to happen.

Use in evaluation of user interfaces

Typically, an evaluator of the user interface will pose a series of questions for each of the cycle's steps, an evaluation of the answer provides useful information about where the user interface may be inadequate or unsuitable. These questions might be:

• Step 1, Forming a goal:
  • Do the users have sufficient domain and task knowledge and sufficient understanding of their work to form goals?
  • Does the UI help the users form these goals?

• Step 2, Translating the goal into a task or a set of tasks:
  • Do the users have sufficient domain and task knowledge and sufficient understanding of their work to formulate the tasks?
  • Does the UI help the users formulate these tasks?

• Step 3, Planning an action sequence:
  • Do the users have sufficient domain and task knowledge and sufficient understanding of their work to formulate the action sequence?
  • Does the UI help the users formulate the action sequence?

• Step 4, Executing the action sequence:
  • Can typical users easily learn and use the UI?
  • Do the actions provided by the system match those required by the users?
  • Are the affordance and visibility of the actions good?
  • Do the users have an accurate mental model of the system?
  • Does the system support the development of an accurate mental model
    Mental model
    A mental model is an explanation of someone's thought process about how something works in the real world. It is a representation of the surrounding world, the relationships between its various parts and a person's intuitive perception about his or her own acts and their consequences...
    
    ?

• Step 5, Perceiving what happened:
  • Can the users perceive the system’s state?
  • Does the UI provide the users with sufficient feedback about the effects of their actions?

• Step 6, Interpreting the outcome according to the users’ expectations:
  • Are the users able to make sense of the feedback?
  • Does the UI provide enough feedback for this interpretation?

• Step 7, Evaluating what happened against what was intended:
  • Can the users compare what happened with what they were hoping to achieve?

Further reading

• Norman, D. A. (1988). The Design of Everyday Things
  The Design of Everyday Things
  The Design of Everyday Things is a best-selling book by cognitive scientist and usability engineer Donald Norman about the design of simple objects, and why some objects please their users while others frustrate them....
  
  . New York, Doubleday/Currency Ed. ISBN 0-465-06709-3

Related terms

• Gulf of evaluation
  Gulf of evaluation
  In computer science, the gulf of evaluation is the degree to which the system/artifact provides representations that can be directly perceived and interpreted in terms of the expectations and intentions of the user...
  
   exists when the user has trouble performing the evaluation stage of the human action cycle (steps 5 to 7).
• Gulf of execution
  Gulf of execution
  Gulf of execution is a term usually used in human computer interaction to describe the gap between a user's goal for action and the means to execute that goal...
  
   exists when the user has trouble performing the execution stage of the human action cycle (steps 2 to 4).

• OODA Loop
  OODA Loop
  The OODA loop is a concept originally applied to the combat operations process, often at the strategic level in military operations. It is now also often applied to understand commercial operations and learning processes...
  
  is an equivalent in military strategy.