It is common knowledge that as we get older, our memory capacity can decrease. But new research suggests that both older and younger people have the same memory capacity – only, younger people are able to view memories in “high definition.”
This is according to a study recently published in the journal Attention, Perception & Psychophysics.
The research team, led by Philip Ko of Vanderbilt University in Tennessee, set out to investigate visual working memory (VWM). This is described as the ability to retain a certain amount of visual information without visual stimuli.
The investigators note that previous research has shown that the aging process impairs the encoding to VWM, but they say aging is “likely to affect multiple stages of VWM.”
With this in mind, the team set out to determine the process in which both older and younger adults retrieve their VWM.
For the study, the researchers recruited 11 participants of an average age of 67 years, and 13 adults around 23 years old. All participants were asked to carry out a talk called “visual change detection.” This required subjects to view two, three or four colored dots, and memorize their color.
The dots then disappeared and the participants were presented with one dot in either a new color, or one of their memorized colors. They were asked to state whether the color of the dot was the same or different to their memorized colors.
Their responses were used to measure the accuracy of their memory, in what the researchers refer to as a “behavioral measure,” and the researchers measured the neural activity involved in the participants’ memory capacity using electroencephalography (EEG).
The EEG revealed that both older and younger adults demonstrated similar levels of neural memory capacity when attempting to remember their memorized colors. This means both groups stored the same number of items in their memory.
However, younger adults were better able to recall their items compared with the older adults.
The investigators say their findings suggest that younger adults are able to store items in their memory capacity at a higher resolution than older patients, which is why they are better able to recall their memories.
Additionally, the researchers hypothesize that younger adults may also be able to use a different form of visual memory, called “perceptual implicit memory,” which may improve their ability to recall stored memories.
Explaining the findings further, Ko says:
“We don’t know why older adults perform poorly when their neural activity suggests their memory capacity is intact, but we have two leads.”
“First, further analysis of this current dataset and other studies from our laboratory suggest that older adults retrieve memories differently than younger adults.
Second, there is emerging evidence from other labs suggesting that the quality of older adults’ memories is poorer than younger adults. In other words, while older adults might store the same number of items, their memory of each item is ‘fuzzier’ than that of younger adults.”
The researchers say this is the first study showing a disassociation between behavior and neural activity in the VWM of older adults.