Computing devices are becoming increasingly ubiquitous. Many of us share information amongst the laptop, home and office computers. The boom of mobile telephony has introduced one of these devices into each and every pocket and it’s also quite common to have a (pompously so called) personal digital assistant or PDA that serves as agenda, notebook, clock and many other things. The rise of WiFi poses the possibility that all of them talk to each other without the need of wires.

From 1960 up until now the relationship between humans and computing devices has been constantly changing. According to Roel Vertegaal* director of the Human Media Lab at Queen’s University in Kingston, Ontario, Canada, this relationship has changed in the following way:

Many to one	One to one
One to many	Many to many
Relationship between human and computing devices. Images by the author, based on the diagrams of Roel Vertegaal's article Attentive User Interfaces  appeared in  Communications of the ACM, March 2003, Vol. 46, No. 3 pp 33

• 1960s-1980s. Many people connected to one mainframe. The user interface is the command line. The user interrupts the computer by issuing commands. The computer distributes turns among the users. A “many to one” relationship.
  
  
• 1980s-1990s . One person, one computer. The Personal Computer era. The user interface is the command line but quickly changes to the visual metaphor of the windowing systems. The user interrupts the computer by issuing commands, or using the mouse in a rich context environment. The computer interrupts the user by issuing alarms and messages. A “one to one” relationship.
  
  
• 1990s-2000s. People have different computing devices, including mobile phones, PDAs portable computers and other devices. All of them interrupt the user by issuing alarms and messages and competing for his/her attention, for example when a phone call arrives or the alarm for an appointment rings. It’s a "one to many" relationship.
  
  
• 2000s-2010s. All the above mentioned devices are interconnected by wireless technologies issuing interruptions to the user and amongst themselves according to their different schedules and the communication established between them, and with other users and their respective devices. It’s a “many to many” relationship.

Until now each device has been acting without taking into account the other ones that need the attention of the user. Consequently the different devices we own compete for our attention, leading to a critical usability issue. 

In order to improve this situation, researchers are beginning to work on interfaces that negotiate the timing and the amount of communication they hold with the user. They are called Attentive User Interfaces (AUIs) because they try to monitor where the attention of the user is focused, weighing up the importance of the information they supply with the estimated priorities of the user’s focused activity.

AUIs use specific input, output and turn-taking techniques to determine what task, device or person a user is attending to. This is done by detecting a user’s presence, orientation, speech activity and gaze and statistically modelling attention and interaction in order to establish the relevance of information that could be presented to the user and the urgency of doing so in the context of the current estimated activity.

Four elements at least build up this type of interface:

• Visual attention: A great deal of information about where the attention of the user is comes from tracking where his or her eyes are aiming at. It’s probably the most important input technique.
  
  
• Turn-taking techniques that allow groups of devices to optimise the interaction with the user.
  
  
• Modelling techniques for the attention of the user in order to estimate what the user is interested in, taking the appropriate decisions regarding turn taking and scheduling of interruptions to him/her.
  
  
• Focus + context displays and visualisations that use the information that the user is focused on to enhance or decrease the information density in a particular zone of the display.

Attentive User Interfaces have the potential to make our life simpler in a world where our time is an increasingly scarce resource hounded by the interruptions of our e-mail, agenda, mobile phone and the other devices that accompany us at all times.

* Attentive User Interfaces in Communications of the ACM, March 2003 / Vol. 46, No. 3

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