Good Design: Characteristics & Flaws (Conventions, Affordances,…
Good Design: Characteristics & Flaws
"A large peg cannot fit into a small hole" (Norman, p. 119)
Example: cylindrical batteries
"Each culture has a set of allowable actions for social situations" (Norman, p. 122).
Example: violating cultural norms in an elevator
"Semantic constraints are those that rely upon the meaning of the situation to control the set of possible actions" (Norman, 123).
Example: Only one way to sit on a motorcycle
"There is a logical relationship between the spatial or functional layout of components and the things that they affect or are affected by" (Norman, 123).
Example: one piece leftover after repairing a mechanical object means you didn't do it right
Conventions, Affordances, Signifiers
"A form of cultural constraint associated with how people behave" (Norman, p. 124).
"Violate conventions and you are marked as an outsider" (Norman, p. 125).
"When carefully designed, with a good, detailed analysis of the activities to be supported, the mapping of controls to activities works extremely well" (Norman, p. 125).
A form of physical constraint
"Situations in which the actions are constrained so that failure at one stage prevents the next step from happening" (Norman, p. 132).
An interlock forces operations to take place in proper sequence
A lock-in keeps an operation active, preventing someone from stopping it too early
A lockout prevents someone from entering a space that is dangerous and prevents an event from occurring
"Refer to the potential actions that are possible, but these are easily discoverable only if they are perceivable (perceivable affordances) (Norman p. 135).
The interpretation of a perceived affordance: Cultural convention
Tells us about things we can't see while our gaze is elsewhere
"…when a person intends to do one action and ends up doing something else" (Norman, p. 156).
Bottom four stages of the action cycle
Description-similarity: the error is to act upon an item similar to the target
Capture: instead of the desired activity, a more frequently or recently performed one gets done instead
Mode-error: when a device has different states in which the same controls have different meanings
"…[occur] when the wrong goal is established or the wrong plan is formed" (Norman, p. 157)
Top three stages of the action cycle
Result from poor interpretation, faulty rules, or incorrectly predicted outcomes
Misalignment between behavior and situation, especially when situation is novel enough that no skills or rules cover it
Can lead to mistakes if the failure leads to forgetting the goal or plan of action
Root cause analysis
The 5 why's: not an exhaustive list for the cause of a problem but a good place to start
"The tendency to stop seeking reasons as soon as human error has been found is widespread" (Norman, p. 152).
I enjoyed these chapters and found them easy to read and informative. I'm not sure how to connect this kind of thing with instructional design theory, but I'm enjoying the cognitive psychology aspect for now.