Distraction is an ageing problem

This blog posting is a bit “hard going” but the conclusions are massive for Web design and older audiences. I have used a lot of the original text from this article.

Research, conducted by University of California, Berkeley in 2005 discovered that the brain's capacity to ignore irrelevant information diminishes with age (i.e. getting distracted when looking at the wall of faces in a crowded room when trying to find a long-lost friend). And, to enhance relevant information - such as the face of a new acquaintance met during the search for the old friend. This process is known as top-down modulation.

In the 2005 study, younger and older adults were given a visual memory test in which they were shown sequences of images (sets of two faces and two scenes), told to remember a specific category, and then asked to identify an image from that category nine seconds later. Using magnetic resonance imaging they found that the neurones of the older participants (ages 60 to 72) responded excessively to the images they should have ignored, compared to the younger adults (ages 19 to 33). This attention to the distracting information directly correlated with how well the participants did on the memory test.

The same team has recently concluded another study using a technique (EEG) that measures the speed of neural processing, to examine the relationship between this inability to ignore irrelevant information and another leading hypothesis about cognitive ageing, the brains decreasing speed to process information. According to this latter theory, if information is not moving quickly onto the brain's processing channel there is a backup of data that delays information processing that disrupts memory formation.

The new study, involving the same visual memory test used in the previous research, revealed that both brain processes - the capacity to ignore irrelevant information and the ability to process information quickly - diminished with age and, in fact, worked in tandem.

The older participants in the study had trouble suppressing unnecessary information, but only because the speed with which they processed the irrelevant data decreased.

The study showed that the brains of older adults have a deficit in suppressing irrelevant information during visual working memory encoding, but only in the first tenth to two tenths of a second of visual processing.

Moreover, despite the ageing brain's ability to suppress extraneous information in the ensuing milliseconds, the memory deficit persists so that the interference by irrelevant information apparently overwhelms our limited working memory capacity. It is like a computer dumping too much information into the memory cache.

Nobody knows why these changes occur. Let’s hope somebody discovers the answer and so we can do something about it!

I am about to make a horrible non-scientific leap of logic. To me, as an ex-scientist, these results shout out the need to reduce the amount of distraction we put onto web sites that are being used by older people.

To give a young web site designer a feel for what is going on when an older person tries using a web site that is littered with distracting functionality. Have a go at this test.Plug in your iPod, select a track you have never played and start memorising the lyrics. At the same time start a Skype chat with a friend and simultaneously start searching for the cheapest place to buy your next holiday in Patagonia. Difficult or what.

Web 2.0 technologies are a joy to use but also make it very easier to build sources of distractions into our Web sites. If we want to make life easier for older people we need to start de-cluttering the experience of using web sites. Dick Stroud

The first study (October 2005) can be found in Nature Neuroscience
The second study (Sept 2008) is called Age related top-down suppression deficit in the early stages of cortical visual memory processing (Adam Gazzaley plus lots of other clever guys).