DDT or Designed Dwell Time

Exhibit DDT or Designed Dwell Time

DDT - Managing the time factor in interpretive exhibits

In the field of heritage interpretation, we use the term "dwell time" to mean the period of time an audience spends engaging in an exhibition space or a specific exhibit or activity.

DDT or Designed Dwell Time refers to the specific amount of time that an interpretive planner or exhibit designer has designed an exhibition space or a specific exhibit or activity to complete.

As professional heritage interpretation planners and exhibit designers we know how long, on average, it takes for someone to interact with an individual exhibit or media....we know because we planned it that way!

By adding the time it takes to interact with each exhibit within an exhibit space, and adding in an element of time it takes to move from one exhibit to another, adding time for cognitive absorption, we can accurately calculate the average design dwell time of a single exhibit, a series of exhibits, a whole exhibit space or even a whole museum, visitor centre, historic house, zoo, heritage trail, and so on.

So why is exhibit DDT it important?

When planning an exhibit, exhibit space or a whole museum it is important to know how long the average visitor will spend being engaged. If the DDT for your site is just say 30 minutes it may not be engaging enough, or worth the emotional and financial investment it takes for a visitor to travel to your site....you may not have a critical mass of experience to attract and hold visitors.

On the other hand if the DDT for your exhibit space is 2 hours you could suffer from exhibit overload. Exhibit loading is the term we use to describe the amount of time and energy (either emotional, physical or psychological) that each exhibit requires the visitor to invest or use up in the interaction with an exhibit.

Think of the visitor entering an exhibit space with 100% of enthusiasm, interest and energy. As they move through the exhibit space, interacting with each exhibit they are "using up" energy and their interest begins to drop. They start to get psychologically tired and overloaded with information and stimuli.

Generally about 40 to 45 minutes is about the maximum you can engage the visitor in one session before they have had enough and head for the gift shop, restaurant or the exit! Remember your visitors are at your site to enjoy themselves and have fun. Humans can usually concentrate for around 20-minutes at a time IF they are engaged, so it is a good idea to plan in a rest pace of low insensitivity activity 20-minutes in to your interpretive presentation.

On a larger site you can plan a number of separate exhibit spaces based around your planned interpretive program or sub themes, which of course link together and address your main / site interpretive theme. The route to, from and between these separate exhibit spaces or galleries can pass through quiet areas, a coffee shop, restaurant, retail areas, demonstration areas, movie theatres and so on. This breaks up the overall experience into bite size chunks which avoids exhibit overload issues.

Remember too, to think about the PAOT (people at one time) factor - If most of your daily visitors all arrive on site at 10:00am, or 5 coach loads all arrive at the same time you could struggle with "bunching" and managing visitor flow around your spaces.

By Crispian Emberson