Eight Golden Rules: Rule 8 - Reduce Short Term Memory Load

A regrettable consequence of getting older is that both our senses and our memory tend to be less acute.  While I scoffed at this notion when I heard about it in HCI class back in my 20s, it is now a fact of my daily life.  The National Institute of Health (NIH) describes how changes in our brains as we get older may cause us to take longer to learn new concepts or remember information.

Even at our best, our working memory can only handle so much information at once.  In 1956, psychologist George Miller introduced the world to the theory of Chunking.  This notion says that the human working memory can handle seven plus or minus two “chunks” of information while we’re processing information.  So, if you have to mentally juggle between five and nine pieces of information while solving problems, most people are fine.  Beyond that, get out a pen and paper.

An interesting corollary to this you can use this notion to your advantage by changing how you mentally “chunk” information.  For example, let’s say you wanted to remember the ICS phone number (617-621-0060) to repeat it back to someone.  That’s 10 discrete pieces of information, or 10 single digits, right? Well, if you live in Massachusetts, you are likely to know that 617 is the area code for Boston and the surrounding area. Thus, you can take those first 3 numbers and reduce them from “6, 1 and 7” to “617”.  Now we’ve gone from 10 pieces of information to a more comfortable 8.

How does this impact User Experience (UX) design?  Simply put, don’t make your user remember more things than necessary.  If your system has information scattered across different screens that are needed for one task, consolidate those screens.  If a user enters information into a form, don’t make them re-enter it during a validation sequence; see my early post about preventing errors for more discussion on this notion.

This concludes our series of posts detailing Shneiderman’s Eight Golden Rules of Interface Design.  On behalf of the ICS User Experience Design (UXD) team, we hope you’ve found them informative.  If you happen to be a software developer who is designing screens yourself without the benefit of working with a UX team, hopefully this series provided some actionable ways to make your user interface better for your end users.  Trust me, they will thank you for it.

References

1. National Institute on Aging website, last accessed, May 2, 2016, https://www.nia.nih.gov/health/publication/forgetfulness

2. Miller G. A. (1956). The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychol. Rev. 63, 81–9710.1037/h0043158