Experience always occurs in time. We can measure objectively the duration of an event or action-minutes, hours, seconds, and so on. But to measure the length of an experience, we should consider subjective time. Time perception is influenced by several conditions:

• The individual's state of mind
• The events that are taking place
• The environment and the context within which the experience occurs

These, and other factors, affect how a person experiences the passage of time. Time passes fast when we are having fun, and drags on when we are bored. When we wait for an exciting event such as a vacation abroad, the time seems to stretch forever before we get on the airplane, but then, the trip is over in what seems as an instant.

Time is slow when we are tired, fast when our mind is engaged, rushing when we want to accomplish more than what we can, and crawling when we are waiting for a bus on a cold rainy day. Moreover, the perception of passing time operates simultaneously on two planes, as you may have observed if you ever felt like, "the days go slowly, but the years rush by." In our mind, time is elastic - it can be both fast-moving and slow-moving at the same time.

The terms Instant Gratification and Planned Obsolescence are rooted in the association of time and pleasurable reward. When technology and design are added to the product design mix, time becomes an important influence on the decision-making process of people. Instant Gratification--reducing to zero the time between desiring something and having it, creates a mindset that fast is good and slow is bad. To be fast, things need to be as simple as possible, or appear to look simple, hiding complexity under a beautiful design.

Products that rely heavily on the latest technology have a short life cycle, because within a couple of years, newer, more powerful versions are released, making the previous generation obsolete. Each new generation of smartphones, for example, features better, faster and more stunning design--typically--thinner and lighter, than its predecessors. To upgrade, one's previous device, which still functions just fine, will be replaced--but this is something most consumers seem to be interested in--either to stay trendy and to enjoy the benefits of the latest version.

Whereas the physical dimension of our world: width, length, and depth, are verifiably measurable, time, the fourth dimension, is both objective and subjective, measureable, and ephemeral. Experience designers are thus especially sensitive to the role of time in the product they design--the spectrum of creating a timeless experience, while reaching for the optimal duration for each interaction.

We live through time in a few ways:

• We orient events and ourselves in a continuous vector of time--behind us is the past, we are experiencing the present, and ahead of us, is the future.
• All languages have grammatical tenses, which is how people have expressed the passage of time throughout civilization.
• Physically, we live in the present, which makes some experiences special to us because they attempt to transcend time--we forget ourselves in the experience, and don't notice time passing by.
• Duration of events is another way we experience time. A slow website is viewed negatively, because we expect the response time to be near instantaneous.