3 sets of user needs

in a discussion on Six Sigma methodology and Kano Analysis as applied to IxD, Mike Baxter summarized Dr. Noriaki Kano's principles on the 3 sets of users needs:

Basic needs are unspoken (latent) needs. Users don't tell you about them when asked. They are the underlying expectations about what the product/system will offer and hence are taken for granted. When you buy a car, you expect it to have wheels. Ask any buyer what they are looking for in a new car, however, and they are unlikely to mention that it needs to have wheels! This may seem obvious but a friend of mine was caught out on this a couple of months ago - they bought an budget all-in-one TV and VCR only to find when they got it home that it couldn't record on one channel whilst playing a different channel. For him, this had been a latent, basic need. The dynamics of basic needs are that they lead to dissatisfaction when not met but don't lead to any positive sense of satisfaction when met.

Performance needs are spoken (manifest) needs. These relate to the range of
features that are recognised as current differentiators in the marketplace -
the more of these features that any one product offers the higher
'performance' it is seen to have. In mobile phones at present, the
performance factors include downloadable games/ringtones, built-in camera,
email/web access, tri-band etc. The dynamics of performance needs is that
they are additive and move perception of quality from dissatisfaction (this
product/system has a below-average set of features) to satisfaction.

Excitement needs are unspoken (latent) needs. They are what the user doesn't
know they need but are excited by when they see it. They are the 'spark' or
the 'factor X' that good design can add to a new product/service. The
classic example was the Sony Walkman - the market research found nothing to
suggest that customers wanted such a product - but when customers saw it
they fell in love with it. The dynamics of excitement needs is that failure
to meet these needs causes no dissatisfaction but meeting an excitement need
causes ... well excitement - and often higher levels of satisfaction that
any number of accumulated performance needs.

One final thing to note is the dynamic nature of users' perception of needs.
An excitement factor is only exciting once. Once it is out there in the
marketplace, it becomes a performance need and is balanced against all the
other performance needs. After a while, performance needs can become basic
needs - in the 1950s one of the great excitement factors in televisions was
the introduction of colour screens. Now, colour TV is a basic need.

(via ID Discuss)