Month: August 2018

Don Norman, engineer, professor of psychology and cognitive science, and author of the esteemed book The Design of Everyday Things, is considered a human-centered design (HCD) thought leader. He believes engineers and designers must abstain from making assumptions and instead observe and understand how humans interact with the world (e.g. a particular object or system) before they imagine, prototype, and test solutions.

Getting the specification of the thing to be defined is one of the most difficult parts of the design, so much so that the HCD principle is to avoid specifying the problem as long as possible but instead to iterate upon repeated approximations. –– Don Norman

In The Design of Everyday Things, Norman spotlights the importance of discoverability. Effective design encourages and allows humans to easily discover how an artifact is used. Careful attention to four principles of interaction –– affordances, signifiers, mapping, and feedback –– lead to competent, translatable design. To better understand the facets of these principles, I assessed how the Museum of Modern Art-inducted Alessi 9090 stovetop espresso coffee maker (pictured right) stands up against Norman’s definitions.

Affordances

An affordance describes the relationship between a physical object and an agent of interaction, be they human, animal, machine, or robot.

An affordance is a relationship between the properties of an object and the capabilities of the agent that determine just how the object could

possibly be used. A chair affords (“is for”) support and, therefore, affords sitting. –– Don Norman

Signifiers

A signifier amplifies usage by indicating where and how a particular interaction should occur.

Affordances determine what actions are possible. Signifiers communicate where the action should take place. –– Don Norman (emphasis mine)

• The hollow base includes a screw that can be seen from the outside and inside of the product. To avoid overfilling the base, one must fill it with water to the bottom of the screw and no fuller. I cannot remember how I learned this fact, whether it was knowledge conveyed by a salesperson or contained in a manual. To me, however, it is not intuitive. Norman believes simple appliances should not require written instructions; their uses and functionalities should be readily understood. By that standard, the Alessi 9090 trips up where the screw-as-water-line is concerned.
• The basket, which holds ground espresso beans, sits perfectly atop the base. There is no other way to arrange the basket (hooray!).
• The vessel contains a handle fixed by a hinge at the top and loose at the bottom. The spout side of the vessel includes a cutout that neatly fits around a small piece of metal on the base. The handle is hollow and its bottom securely clicks onto a handle-side piece of metal on the base. These signifiers are brilliant. A human can quickly deduce how to secure the vessel to the base.
• The lid includes two signifiers: a triangular spout and a metal tab that encourages pushing. The former tells a person how to situate the coffee maker to nonviolently pour the coffee, and the latter encourages the agent to push the tab to see if the coffee is done and the machine is working properly. Once a finger is released from the tab, the lid closes via gravity.

Mapping

Mapping is an important concept in the design and layout of controls and displays. When the mapping uses spatial correspondence between the layout of the controls and the devices being controlled, it is easy to determine how to use them. –– Don Norman

Feedback

Feedback tells a human that a particular process is working and, optimally, indicates the process stage. For instance, when one takes an online survey, they often see a progress bar that showcases what they have done and how much more they have to accomplish before the activity is completed.

Feedback [communicates] the result of an action. –– Don Norman

The Alessi 9090 provides feedback in two prominent ways.

• When the vessel is clipped into the base on both the spout and handle sides, a distinctive click can be heard. This tells an agent the coffee maker is secured and ready to use.
• As percolation occurs and coffee fills the vessel, one can hear a bubbling noise which indicates the coffee is brewing. Once the bubbling noise ceases, one knows the coffee maker should be removed from heat and the coffee consumed.

The four principles of interaction provide a framework for engineers, designers, and makers of all variety to build humane designs that center the organic behaviors and needs of their intended audiences. Up with Norman! Up with empathetic design!