No one likes to feel like they’ve lost control. The nature of a pervasive application is to seamlessly integrate into a person's normal routine. This is largely accomplished by making assumptions about the shopper based on their actions and interactions, then executing what is believed to be the most relevant response. It’s impossible to make accurate assumptions 100% of the time. We need to accept that our applications won’t be perfect and design to error scenarios. Allow shoppers to step in, turn off auto-pilot, and take control for themselves.
1 Allow shoppers to take over.
Manual control of the system is very important to users of pervasive applications. We must allow them the freedom to interact with the system to inspect, override, discard, revert, store, retrieve, focus, preview, and generally kick the tires. Give them the ability to quickly explore the application and environment from the smallest detail associated with a product to the entire context of the store. These manual explorations support shoppers in making decisions as well as help them assess their location and orientation in the full context of the store.
2 Offer control in return for their trust.
By allowing shoppers to control their experiences as well as the information we collect, we build trust that we are here to help them and not just sell to them. Build trust that we’re not just taking their information, but using it to help them. Most people don’t trust sharing their personal or behavioral information. So, we must be transparent in our intentions and let them control what they share with the application. More on this in Earn their Trust.
8 references informed this principle
 Darken, RP & Peterson, Barry, Spatial orientation, wayfinding, and representation, Handbook of virtual environments, 4083, 2002.
 Kulkarni, Ajay, Design Principles of a Reactive Behavioral System for the Intelligent Room, Bitstream: The MIT Journal of EECS Student Research, 1-6, 2002.
 Malaka, Rainer & Porzel, Robert, Design Principles for Embodied Interaction: The Case of Ubiquitous Computing, KI 2009: Advances in Artificial Intelligence, 2009.
 Pantano, Eleonora & Laria, Giuseppe, Innovation in Retail Process: From Consumers' Experience to Immersive Store Design, Journal of technology management and innovation, Vol. 7, No. 3, 194-206, 2012.
 Sagaran, Camarasen; Dehghantanha, Ali & Ramli, Rohaini, A User-Centered Context-Sensitive Privacy Model in Pervasive Systems, 2010 Second International Conference on Communication Software and Networks, 78-82, 2010.
 Wobbrock, Jacob O.; Kane, Shaun K.; Gajos, Krzysztof Z.; Harada, Susumu & Froehlich, Jon, Ability-Based Design, ACM Transactions on Accessible Computing, Vol. 3, No. 3, 1-27, April 2011.
 Zhang, Xiaohui & Uruchurtu, Elizabeth, A User Experience Perspective of Design for Context-Aware Adaption, 2011 Seventh International Conference on Intelligent Environments, 1989, 322-325, July 2011.
 Ziefle, Martina & Rocker, Carsten, Acceptance of pervasive healthcare systems: A comparison of different implementation concepts, Proceedings of the 4th International ICST Conference on Pervasive Computing Technologies for Healthcare, 2010.