.
Design Course
Introduction to Cognitive Ergonomics in Design
Cognitive Ergonomics in Design
by
Procedure
In general a team of experts who has prior knowledge about usability engineering or product design are participated in this method. They walk through several scenarios and identify different cognitive steps that are required to use a product/ system successfully by users. There are six basic steps in CWM to design a product / system (Lewis and Wharton, 1997; Polson et al., 1992; Sears, 1997; Sears and Hess, 1999; Wharton et al., 1994). These are as follows:
- Develop a full understanding of target users’ prior knowledge.
- Find out tasks that represent what users will do in the real world.
- Create detailed task-based scenarios.
- Walk through the correct action sequences necessary to complete the selected tasks.
- Identify and discuss the task-relevant cognitive processes the user must undergo to successfully complete the action sequences.
- Identify the learning or adaptive responses that are most likely to occur when the user is exploring the product.
Table 9. Exploratory Behavioral Tendencies and Example for a PDA (Personal Digital Assistant)
|
Exploratory Behavior |
Description |
PDA Example |
|
Goal setting |
User determines goal to be accomplished |
Develop and send a text message |
|
Interface exploration |
User searches for actions to support goal (icons, menus) |
Find “Applications” menu |
|
Action selection |
User determines action to move toward goal; selects action |
• Select “Applications” menu (level 1), press <OK> • Select “Text Message” from menu (level 2 or submenu), press <OK> • Select “Edit” • Select mode — keypad or stylus (activated upon selection) |
|
Performance and evaluation |
User performance action and evaluates system feedback |
Enter message, press <DONE> Review displayed message, press <SEND> or <EDIT> |
Source: Smith-Jackson,T. L. (2005)
There two tables which are furnishing example of exploratory user behavioral tendencies (Table 8) and sample problem list identified from cognitive walk-through method (Table 9). These two tables will be helpful for proper understanding of the cognitive walk-through method.
Table 10. Sample Problem List Generated from a Cognitive Walk-Through
|
Function |
Problem Description |
User Assumption |
|
On/Off |
At the power-up sequence, there is a long delay (5 sec) before the standby display is activated |
User may assume product is not functioning and may press the <POWER> button again, which will then turn the device OFF |
|
On/Off |
At power-off, a short press leads to a selectable options list requiring the user to select “SHUT DOWN” |
Experienced users may not have a problem. Inexperienced users may not understand the term “SHUT DOWN” and may continue to press other buttons to turn off the phone. A common reaction at that point is to remove the battery pack. Repeating this action could eventually damage the phone. |
|
Soft keys |
Activators for the three soft keys do not physically map to the display key |
Novices may not understand soft-key assignment and will not know the functions of the three hardware keys on the keypad. During exploration, other keys will be pressed, including navigation arrows. |
|
Receiving a text message |
There is no information available after reading a message that allows the user to delete the message |
After the message has been read, the user will not know which button to press to delete the message. It is possible that a user will press the <END> key assuming that since <END> terminates voice calls; it will also delete text messages. But, <END> returns the user to standby without eliminating a text message. |
Source: Polson, P.G. et al. (1992)