Fifth Design Sprint: Geared Modes


Investigating dynamic mapping as a way to combat mode confusion

The aim of this sprint was to try and see how a users place in a system can be better understood by the user by creating a physical representation of their location. The work in this sprint focussed on the idea of clearly identifying the mode of the interface.


What is a mode? 

A mode is a segment of an interface that is designated to one specific task. Almost all controls within a mode relate to one specific function

In his book The Humane Interface, Jef Raskin defines a mode as:

"An human-machine interface is modal with respect to a given gesture when (1) the current state of the interface is not the user's locus of attention and (2) the interface will execute one among several different responses to the gesture, depending on the system's current state." (Page 42)."

Within the context of an HMI system, modes are important ways in which drivers can complete specific subsets of tasks that are related to each other. These might be things like navigation, entertainment, communication or car control.

Mode Confusion

Mode confusion is one of the most common causes of error with interactive systems. It occurs when a user has the wrong understanding of the current mode of a system, and engages with the system as if they are in another mode.

This is a major problem in automated flight systems, where pilots need to have clear understanding of how much control they have over the airplane at any given time. 

In HMI systems the problem is less severe, however it is still important as if the driver has a clear idea of the mode of the system, it will reduce the amount of attention they need to give the interaction with the system.



During this week I drew on some existing experiences I had while working on HMI systems during my internship at Frog Design. My aim was to explore how modes might be explicitly communicated to the user through the physical nature of the control. 

The initial inspiration was the idea of the forked gear lever in manual cars. This control provides the user with a clear physical representation of which gear the car is in by having a unique physical position for each gear. The driver needs to physically move the control from one position to another to change the gear. 


Natural (but dynamic) Mapping

My goal was to explore how mapping between a screen interface and a physical control might be enhanced by making the link between the two really clear. 

I used processing to create a simple mockup of an interface with three distinct tabs representing three modes of an HMI system. The use of tabs is a common method of segmentation in HMI so this was a good concept to test. The idea was to link the function of a touch interface with the function of a physical control, allowing them to represent the same function at the same the time.

This means that when the screen was in the red tab, the control would move to the same location and allow access to those functions. The controls were linked so that interacting with either the screen or with the physical controls would both adjust the other to present the same function.


What I Learned

This sprint was valuable as it helped me to explore the value of representation at all stages of design that began to emerge during the second sprint. 

The relationship between the physical control and the screen was also really interesting to explore. Mapping seems to really help with understandability of location within a system, and being able to provide some additional information with the location of the physical control seems to have benefits as well.