2.15.06

Lou Fuiano
ITI Spring 2006
Duff

The Design of Everyday Things
Chapter 5
TO ERR IS HUMAN
Donald A. Norman

The Anatomy of Swearing

I finally found a car that makes it impossible for me to lock myself out. Quite frankly, it's a revelation. before I go on, I should mention that keys in general were a chronic problem for me. I never liked that metallic mess of keys in my pocket, so I would invariably take the keys out of my pocket whenever I settled in somewhere, often leaving them there. I was so happy when it became fashionable to wear your keys hanging from a belt loop like any self respecting building superintendent. That was a big first step for me. The next was when we recently bought a Volvo. Sure it's loaded with safety features, but it's most endearing quality is that it will not lock unless I lock it from the outside. This is very important to someone who has, on more than one occasion, slammed the locked car door shut, with the keys inside... while the motor was running. The problem with unconscious behavior is that it seems to govern your actions even when your not really multitasking.

I'm sure this chapter spoke to many of us. Driving to a new destination and finding yourself driving to work on you're day off is all too familiar. While the breakdown of the slip is very useful, the models of human thought create a new discussion. Norman mentions that we generally perceive memory as pictures in a scrap book. When really, it's kind of, in his words, "mushed together". He also states that "Mental life is not neat and orderly. Instead, it skips and jumps it's way from idea to idea". This ultimately leads to "creative discovery" and inspires "robust behavior". This is a fascinating point because we are always trying so hard to order and organize.These characteristics can also cause human error. Our memory is selective and biased. They are not a systematic analysis. Another contributor to mistakes is the perception of "commonplace" allowing us to coast through and the "discrepant" grabbing all of our attention.

Deep and Wide Structure is a decision making device. Norman mentions how we navigate information based on how choices are offered. Narrow being a selection of one element like an ice cream flavor. The deep decision is rooted in the variation of the element; how many flavors. An excellent application of this is illustrated in the highway road sign that makes use of narrow and shallow choices as it guides you to your destination.

The part of this chapter that brings everything home for me is how designers can build in features to better prevent mistakes or Designing for Error. Norman mentions how faulty design can be responsible for world class disasters. A particularly pointed example for me was the butterfly ballet in the 2000 presidential election that confounded voters and lead to heated dispute one the elections validity.

Forcing Functions seems to provide a remedy for many such mistakes. It also appears to be a bone of contention as well an extremely effective solution. Design works best when it doesn't get in the way. Norman points out several failed designs of forced function that motivate the user to deactivate the very feature that is there to prevent costly, even deadly mistakes. However, when the forced function is designed properly, it can allow us to work gleefully from the sub conscience. As was the case with my locking the keys in the car ever chance I had. This then frees me up to make my mistakes elsewhere.

Notes/Chapter points

SLIPS
Types of slips
capture errors
description errors
data driven errors
associative activation errors
loss-of-activation errors
mode errors

DETECTING SLIPS
design lessons from the study of slips

MISTAKES AS ERRORS OF THOUGHT
some models of human thought
the connectionist approach

THE STRUCTURE OF TASKS
wide and deep structures
shallow structures
narrow structures
the nature of everyday tasks

CONSCIOUS AND SUBCONSCIOUS BEHAVIOR
explaining away errors
social pressure and mistakes

DESIGNING FOR ERROR
how to deal with error-and how not to
forcing functions: interlock, lockin, lockout

A DESIGN PHILOSOPHY

top of page