Behavior Models

There are 6 types of behavior models which are split up into Predictive and Discriptive. Behavior Models help HCI developers and designers understand and work out how the interface will preform tasks and how efficient it is, is it worthy of computer use or device, or is it to slow?

The Predictive models are as of follows:-

• Keystroke-level-model (KLM)
• Throughput (TP)
• Fitt's Law

 The Discriptive models are as of follows:-

• Key-action-model (KAM)
• Buxton's three state model
• Guiard's model of bimanual skill

As there are many predictive and discriptive models I am only going to look at one of each.
 

Predictive

The keystroke-level-model was built and proposed by Card, Moran and Newell in the 1980s. They proposed that it would improve the efficiency of the HCI for an expert user. The keystroke model was made to predict and estimate how long it takes for a user to input letters on the keyboard. The model is made up of 11 steps which is used by both users and organisations however, some organisations who can't afford specialist software usually use this method instead.

The keystroke-level-model measures how long it takes to complete the 5 components that make up the model. The first one is how long it takes to press and release a button on the keyboard, measured in seconds. The second is to point the mouse on the screen and then to see how long it takes to switch hardware devices for example the home button on the keyboard. Fourthly how long it takes for the human brain to prepare to perform an action and Fifthly how long it takes to enter a string of characters and finally how long it takes for the system to preform the action. 

Key-action-model

Computer keyboards to date contain a lot of buttons and functions, the buttons can be categorized into 3 sections: Symbol keys, Executive keys, Modifier keys.

The Symbol keys can deliver graphic symbols such as letters (eofeof), numbers (1234567890) or symbols (!"£$%^&*@) which can then be inputted into a text editor such as word or notepad.

Executive keys are actions that are used and placed at the application or system-level. The keys that are used in executive situation would be the ENTER, F1 or ESC keys.

Modifier keys don't generate the symbols or invoke actions but instead set up a condition that is necessary to modify the effect of a key that was pressed subsequently and provide new options . For example without using SHIFT+1 it would show (1) however if i press SHIFT+1 it will show (!). The key action model basically looks at how users will interact with the HCI using the keyboard and using specific functions.