Activities of daily living, such as grooming and meal preparation, can be thought of in terms of routines that are carried out in a specific order. For example, when making a cup of instant coffee one may place sugar in a cup, add milk, add the coffee grounds, add the boiling water and then stir. Even though it is common to hear about forgetfulness as a part of aging, there is not much research on how a sequence of daily routines are remembered and retrieved from memory in healthy older adults.
Previous research suggests that while carrying out a learned routine, participants make use of sub-tasks to help them remember all the steps. For example, adding sugar is one sub-task of the routine of making coffee, which consists of taking the spoon, dipping it in the sugar bowl, scooping up sugar, bringing it to the cup and pouring it into the cup. These smaller steps are chunked into one action of adding sugar to ease the process of memory retrieval. Creating this adding sugar subtask is referred to as ‘chunking’.
Another component thought to be involved in the process of retrieving sequences or routines from memory is inhibition, or the ability to suppress information. Through the use of inhibition, it becomes easier to retrieve chunks of a sequence that have not yet been completed than it is to retrieve chunks that have been completed. Once the act of putting sugar in the cup is completed, the mind pushes that information back so that it is easier to access the information needed for the next step of putting milk in the cup.
A study conducted in 2010 by Li, Blair, and Chow from Concordia University examined how chunking and inhibition influences the completion of a sequence of tasks in two experiments comparing younger (18-30 years old) with older adults (60-75 years old). They hypothesized that there would be a difference in how older and younger adults chunk information (i.e. perhaps using smaller chunk sizes), and how quickly the chunk of information is retrieved from memory – or the speed of retrieval.
In the first experiment, the task consisted of memorizing the specific order of eight animal images to the point of being able to recite them correctly forward and backward. The sequence of animals, which appeared in increasing size, was as follows: ladybug, butterfly, bird, cat, wolf, zebra, camel, and elephant.
The participants watched as many images appeared on the screen and were asked to click a button on the keyboard only when the image appeared in the fixed order. So, the participants would first watch for the ladybug, then the butterfly, and so on, while ignoring all images that were not next or already completed in the sequence (called distractors).
Using statistical analysis to examine how quickly participants clicked on the appropriate images, and the types of errors that were made, researchers found that both the younger and older adults seemed to chunk the images into groups of two. For example, participants may pair ladybug and butterfly together as a chunk before starting another chunk of bird and cat. In this way, the participant can make recall easier by focusing on 4 chunks as opposed to 8 separate animal units.
However, older adults appeared to access each chunk slower compared to younger adults and younger adults were more efficient at using inhibition to regulate their performance than older adults. Taken together, these findings suggest there are differences in how memory and inhibitory processes affect our sequence of actions as we get older.
Given that older adults have greater difficulties accessing and maintaining the relevant chunk of information in mind, the focus of the second experiment was to see how the use of a memory aid (rehearse chunk items out loud) to reduce demands on memory would affect older participants performance compared to younger participants on the same sequence of activities.
Overall, results showed that older adults made fewer errors during the task when they had rehearsed the sequence out loud than they did when the sequence was not rehearsed verbally. This means that having a memory aid effectively helps them improve their accuracy. On the other hand, younger adults did not benefit from the spoken rehearsal as much as older adults did.
Taken together, the two experiments revealed that the manner in which people chunk sequential information remains stable throughout adulthood. However, older adults seem to be less efficient at retrieving sequence information from memory and benefit more from verbally rehearsing information than younger adults. Results from this study also suggest that older adults are less efficient than younger adults at ignoring information that is no longer relevant. This research supports the idea that memory and inhibitory ability change in relation to age but that certain strategies can improve and facilitate remembering the steps involved in our everyday routines.
Download the complete paper:
Sequential performance in young and older adults: Evidence of chunking and inhibition.
Li, K. Z. H., Blair, M. A., & Chow, V. S. M. (2010). Sequential performance in young and older adults: Evidence of chunking and inhibition. Aging, Neuropsychology, and Cognition, 17, 270-295.