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E44: Human-centred design - some terms from Don Norman (quickisode) · Safe As Podcast

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  On this quickest side of safe, as we dive into human centred
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  design and human factors from Chapter 4 of Don Norman's
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  perpetually awesome The Design of Everyday Things, this chapter
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  explores how we know what to do with objects like a kettle or a
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  doorknob, focusing on the interplay of knowledge in the
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  world, as in perceivable cues and knowledge in your head,
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  conceptual models and learned behaviours.
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  First are constraints. Constraints are powerful clues
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  that limit the set of possible actions, guiding users towards
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  appropriate or intended behaviour.
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  There are four key types. Physical constraints.
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  These rely on the physical properties of an object to
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  restrict actions, like a large peg can't fit into a small hole.
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  Cultural constraints. These are learned societal norms
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  and conventions that dictate acceptable behaviour in certain
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  situations, like knowing to drive on a specific side of the
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  road, or a red light on a vehicle that signifies a brake
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  light, or even just knowing to wear clothes in public.
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  Semantic constraints. These depend on the meaning of
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  the situation. For instance, a motorcycle's
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  windshield must be positioned in front of the rider's face for
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  its purpose of protection to make sense.
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  Logical constraints. These involve an obvious logical
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  relationship between components. The blue light on a Lego
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  motorbike was placed in the last available spot because all the
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  other pieces had specific logical placements.
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  There was nowhere else for it to go.
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  Next we look at affordances. Affordances describe the
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  possible interactions between an object and a person.
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  They signify what actions are possible.
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  For example, a flat plate on a door affords pushing and a
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  doorknob affords turning or pulling.
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  The holes in a pair of scissors afford the insertion of fingers.
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  Also. Signifiers.
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  Signifiers are perceivable indicators that communicate
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  where an action should take place and how it should be done.
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  These can be deliberate, like a push sign on a door or a
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  vertical plate indicating where to push, or accidental, like
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  empty bottles on a wall that subtly signify others have left
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  their items there. Sounds too can be signifiers,
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  like the distinct click of a door bolt.
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  Next to forcing functions, these are strong physical constraints
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  designed to prevent inappropriate behaviour or
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  unintended behaviour by ensuring that one action must be
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  completed or reversed before the next can proceed.
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  Like leaving your keys in your shoes at the front door is a
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  type of forcing function. Interlocks also is another type.
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  Interlocks ensure operations occur in the correct sequence.
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  A microwave that cuts the power the moment the door is opened is
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  an interlock. Next we have lock insurance.
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  Lock insurance keep an operation active preventing premature
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  stopping. A computer asking if you want to
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  save before exiting is a common lock in lockouts.
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  Lockouts prevent entry into a dangerous space or prevent an
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  event. A fire extinguishers pin
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  prevents accidental discharge, and gates at the bottom of
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  stairways can prevent people flaying a fire from entering a
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  dangerous basement. Finally, the thing was Nancy
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  Levinson who once argued that there should be more ways to
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  bring a system into a safe state than to bring it out of a safe
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  state, which could be useful for thinking about the types of
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  constraints we have in our hazardous systems and the types
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  of lock insurance, lockouts, interlocks, et cetera.
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  Let me know how you apply human centred design principles.
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  That's it on this quickest soda safe as Thanks everyone.