Does service with a scowl put you off at lunch? Will you eat more greens if you are surrounded by plants? Does romantic, pink lighting encourage you to linger over your fruit salad?
A new research centre -- dubbed the restaurant of the future -- at the Dutch university of Wageningen hopes to help answer these questions and more by tracking diners with dozens of unobtrusive cameras and monitoring their eating habits.
We want to find out what influences people: colours, taste, personnel. We try to focus on one stimulus, like light, said Rene Koster, head of the Center for Innovative Consumer Studies, as overhead bulbs switched through green, red, orange and blue.
This restaurant is a playground of possibilities. We can ask the staff to be less friendly and visible or the reverse, he said. The changes must be small. If you were making changes every day it would be too disruptive. People wouldn't like it.
The stylish new facility has glass walls, black marble countertops, a polished bamboo floor and self-service tills which allow diners to scan their lunch while they and their trays are weighed by a set of scales built into the floor.
University staff who want to eat at the new restaurant have to sign a consent form agreeing to be watched.
From a control room, researchers can direct cameras built into the ceiling of the restaurant to zoom in on individual diners and their plates. They watch how people walk through the restaurant, what food catches their eye, whether they always sit at the same table and how much food they throw away.
You're already watched by cameras everywhere like 'Big Brother' so what difference does it make here? said Bert Visser, a plant scientist eating a chicken sandwich. Presentation really influences what you choose.
Patricia van der Souven, a research assistant eating pumpkin soup and a salad, agreed: One day they had blue lights and I didn't come in because the food didn't look nice. Blue light isn't warm, it's too business-like.
Koster said researchers can experiment with variables like noise, smells, furniture and food packaging. Is the same ham and cheese sandwich more appealing if it is wrapped in cellophane, under a glass cover or on offer in a vending machine?
They had already noticed that one table where the plastic chairs had pink flowery covers was always occupied.
Koster said observation is much better than questionnaires for consumer research as many choices are unconscious.
I can imagine that music or smell make a difference, said Marco Hoeksma, a consumer scientist for a food company that is working with the university.
It will be very interesting to see what you can manipulate, he said, tucking into a typical Dutch meat and potato croquette.
The new research centre -- which cost almost 3 million euros ($4.26 million) -- was set up in partnership with French catering group Sodexho Alliance and other companies interested in using the restaurant to test their products.
The kitchen staff are also being spied on -- cameras watch how they work with new gadgets like adjustable work benches and cleaning hoses.
It's not to see if they are working hard but how they are working, Koster said.
Koster said he also hopes the centre's work will help governments and health organisations promote a more balanced diet, particularly given the modern rise in eating out.
The centre has an oral laboratory where sensors are attached to the face and neck to monitor how a food tester bites, chews, sucks and swallows a new product, for example a sauce that should taste creamy but contains less fat.
Koster wants to experiment on how to reduce food wastage and encourage people to sort leftovers into a biogas generator, perhaps by telling them how much energy they are saving.
Eating and drinking are primal. How you were brought up to eat is very important so there's no point trying to use words or sanctions, but you can influence behaviour more subtly, he said.