Un-hiding an affordance

Steps in Dawlish, Devon

Steps in Dawlish, Devon

These (pretty shallow) steps in Dawlish, Devon, have been labelled as such, presumably because without this, some visitors wouldn’t notice, and would run, cycle or wheelchair down them and hurt themselves or others. Painting a white line along the edge is a common way of improving visibility of steps, but actual labelling is fairly unusual.

There is some argument that having to label an affordance in this way, rather than it being self-evident (e.g. by making the steps deeper, or putting a handrail, or something), is ‘bad design’, but I’m not sure one way or the other: from a utilitarian point of view, enormous labelling, however ‘ugly’, is probably a surer bet than providing subtle ‘cues’. Nevertheless, the poka-yoke approach would be to design out the problem entirely: make the whole thing a full-width ramp like the section at the side.

A diagram in Bill Gaver‘s classic paper ‘Technology Affordances‘ [PDF, 647 kb] sets out very clearly the importance of an affordance being perceived as such by a user:

From 'Technology Affordances' , William Gaver

In this case we have a hidden affordance (not deliberately hidden) which has been un-hidden by the label – similar to (though not as funny as) the ‘This is a Mop Sink‘ example from Michael Darnell’s fantastic BadDesigns.com:

This is a Mop Sink (image from www.baddesigns.com)


  1. I once went into a gents to find a chap pissing in a flower trough.

    The problem was there was a largish, empty room preceding the gents proper (only accessible via a door behind a sight screen, near the entrance). So, as a newcomer you really had to employ a wall following algorithm to discover this obscured secondary room, because it wasn’t obvious.

    If convention trains people to expect that a large room behind a door marked ‘men’ will be the room expected, then if it isn’t you need pretty good signage to say “No, this is just a large anteroom for man-to-man chatting when large functions are on. The loo proper is in the room via the door behind you, next to the door you came in by – admittedly obscured by a white screen, in this loo-like room with an inviting flower trough in front of you by the window.”

    As for mop sinks, it probably doesn’t need pointing out how confusing bidets sometimes are to cultures that don’t have them.

    On the converse, I was once amused when in a DIY store in the bathroom zone a young girl sat on a loo and got to work, wondering why her older sibling was giggling so much.

    There are some things whose design or use is conventional and is expected to be understood by convention (needing no explanation). Similarly there are resulting conventions that for a particular use one should expect a particular design, and given a particular design one should expect a particular use.

    When these conventions are broken, or people are ignorant of them, misuse or confusion must be expected (unless remedial instruction is provided).

    I’ve often been amused when travelling on old railway carriages, that removed interior handles on doors for ‘safety’, when passengers unfamiliar with this new convention had to rapidly work it out (open window, stick hand out to use exterior handle) in a few seconds before the train set off again. Small signs then affixed saying “To open door, lower window” didn’t always help (probably noted subsequently – or pointed out at the time by RTFM wags).

    Designers who remove handles, taps, buttons, levers, (or introduce them when they are conventionally absent) can cause a lot of grief for those transitioning between conventions – and quite unnecessarily if the new convention isn’t made obvious, or worse still, the new design is short lived.

    Hopefully short-lived like movement sensitive lights in toilets – that are unfortunately not triggered by the movements of those sat in stalls, soon sat in darkness. 🙁

  2. The steps fail as good design _because_ they are ugly. This is public space and it should look as good as possible within reasonable expectations of the context. Painted step edges and labelling might be acceptable in an industrial setting but definitely not here. We’re back to commodity, firmness and delight. There’s not much delight here, except perhaps for passing design theorists.

    A far more elegant design without changing the dimensions of the steps would be to use surfaces that emphasise the horizontality of the design and if necessary, the edges of the steps themselves. Regular rows of rectangular paving parallel to the steps would achieve this, possibly with a change of tone, texture or material at the edges. The steps would be self-evident and legible without resorting to non-integral artifice.

  3. Not clear to me if the ‘mop urinal’ is a hidden affordance or a false affordance. Probably both: it signals urinal, but isn’t; while affording mob washing and failing to signal.

    Many of your archtypal examples fall into this uncanny valley; the bench semi-signals sit down, take a rest, but while also announcing: just don’t get too comfortable.

  4. “Not clear to me if the ‘mop urinal’ is a hidden affordance or a false affordance. Probably both: it signals urinal…”

    Oh, come off it. The thing in that photograph? It doesn’t look in the least bit like a urinal. It more strongly resembles a bathtub. The urinals I’ve seen all are flush against a wall, with a tall ceramic rear portion and an elevated basin at the bottom, and typically a puck of blue sani-flush type stuff in each. Even the self-flushing variety look very different from that mop sink, which is not elevated and has no back, not to mention is down in a corner rather than up on a wall.

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