Contrary to what we have always believed, when it comes to visual working memory there is in fact no neurological difference between young and old people. The elders of society remember just as much as their youthful counterparts. There is however one major difference in the memory of each age group. According to a recent study published in the journal of Attention, Perception and Psycophysics young people have high definition (HD) visual working memory. Older people, on the other hand have fuzzy, low-resolution visual working memory.
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Visual working memory is in many senses the same as short term memory. It simply depends on which theory and definition you ascribe to. Visual working memory is used to rapidly store bits of visual information for a very short amount of time in order to compare information in our visual field. Visual working memory involves both the storage and recollection of information. It is a mechanism of memory that we entirely rely upon to go about our daily lives from day to day. It’s no wonder scientists want to learn more about it.
The study involved 11 older adults of around 67 years of age and 13 younger adults of approximately 23 years of age. Scientists collected behavioral data as well as EEG scans from all members of the group. First, the participants were shown two, three, or four colored dots and asked to memorize their appearance. The dots would disappear, and seconds later a single dot appeared in the garb of either a previously seen color or a new one. The participants simply stated whether the single dot contained a color that was the same or different than the dots shown initially. Additionally, all during the study the scientists took electroencephalographic (EEG) scans of each participant’s brain as it danced along with the technicolor dots.
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As we would expect, the old people didn’t perform as well on the behavioral test. They had more wrong guesses and exhibited a lower visual working memory capacity. The EEG scans painted a totally different story however. According to the scans both groups had a near equal amount of neural activity in the visual working memory centers of the brain. So although both groups stored the same amount of information, the old people still remembered less. Let’s envision this from another angle.
Let’s say that the visual working memory of the young and old can be represented by an online streaming video. While both old and young videos have the same buffer seed, the young can play at a resolution of 1080p, or maybe even 4k, while the old is stuck at a measly 480p resolution. Although the video is being seen at the same time, and at the same speed, the quality between the two is markedly different. In this way a young and old person will have the same visual working memory speed and capacity. The quality of the memory, however, is what will differ greatly.
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The scientists are not actually positive that HD visual working memory is the reason for the young group’s superior performance, but it seems to be the most likely reason according to Philip Ko of Vanderbilt University. According to Ko, a member of the team that worked on the study,
We don’t know why older adults perform poorly when their neural activity suggests their memory capacity is intact… [However] 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.