Lecture 6: Cognitive Ageing Flashcards
Cross- Sectional vs Longitudinal Studies
(Hedden & Gabrieli, 2003 Nature Reviews Neuroscience)- What do we see?, Why are there discrepancies?
Whereas we see that many abilities decline with age in cross-sectional studies, with some staying constant or showing a little improvement, data from the same study that are longitudinal show a much less of a dramatic drop off in performance, and declines are evident in all domains except for processing speed after 55.
People who sign up for longitudinal studies may be more inclined to help- have differing personalities
If the same task is used over again, year after year- then practice effects may bias results
People may die, or stop coming to the testing- biases results
Can’t really get around these disadvantages
Semantic Memory
(Verhaeghen, 2003, Psychology and Aging)- what is it? + results
Conducted a meta-analysis on “crystalized knowledge” growth
- included over 300 studies
- systematic meta-analysis on vocabulary tests
RESULTS
- Positive effect size: Older adults are performing better than younger adults
Overall older adults are 0.80 SD’s higher in vocabulary than younger adults. According to Cohen, this is a large effect size!
-effect sizes are stronger in tests that are multiple choice vs production tests
- there is great variability in the strength of the effect sizes even though they are all positive
- Do older adults “know” more because they have more years of education than younger adults
——-> true! - older adults were benefitted when the test was multiple choice (clearer cues to greater their semantic knowledge
Semantic Memory
(Verhaeghen, 2003, Psychology and Aging)- the Flynn Effect
There was increasing Wechsler Adult Intelligence Scale (WAIS) scores as birth year increased
despite an overall increase in performance over time, older adults still outperform younger adults in vocabulary regardless of when the study was conducted, so the cross-sectional data collection is not limited in this instance by potential cohort effects that explain the age difference
Semantic Memory e.g., Eich et al., 2013, Sitzman et al., 2015 Aging, Neuropsychology, & Cognition- why do older adults substantially outperform younger adults on general knowledge tests?
- semantic memory/ crystalized intelligence is CULTURALLY BOUND KNOWLEDGE
- performance on these tests strongly relies on that fact that you have been exposed to the information before
- fluid intelligence tests are meant to test reasoning ability that is devoid of any cultural influence
THE POINT?
- older adults have had more time and education to be exposed to information—> causing them to show an age-related benefit compared to the typical decline we might expect in memory
Semantic Memory e.g., Eich et al., 2013, Sitzman et al., 2015 Aging, Neuropsychology, & Cognition- why are there differing results across the years?
Participants of today (2013) did better on the first 4 questions
In 1980 7% of the participants knew the answer to “of which country is Baghdad the capital?” compared to 47% of today’s participants.
WHY?
- Iraq is more culturally relevant now than it was in 1980
Semantic Memory (Mayor et al., 1994) Mastermind Study
Mayor (1994) conducted a study where she sent a questionnaire to previous contestants of Mastermind who are in a club together
They were asked the following questions (which could be verified with a video recording of their performance):
- How old when they competed
- How many did you score (i.e., correct answers)
- How many incorrect answers did you give
- How many times did you say pass?
-Of these passes, how many times did you actually know the answer, but were unable to retrieve it at the time (i.e., tip-of-the-tongue, TOT)?
RESULTS
- observed is that accuracy on the specialized subject questions was not at all correlated with age, but general knowledge accuracy was positively correlated with age
CONCLUSIONS
- semantic memory improves as people grow older
- BUT If the knowledge is very specialized, then it doesn’t really matter how old you are because you have devoted a lot of time and energy toward that domain regardless of your age
Semantic Memory (Laver & Burke, 1993) Network models- spreading activation + semantic priming
- due to their breadth of experience and education opportunities older adults have a more densely networked semantic memory
HOW IS IT MEASURED?
- measured implicitly by looking at semantic priming (participants view a list of words and non-words and have to decide whether they are words or not as fast as they can)
RESULTS
A meta-analysis of this effect by Laver & Burke (1993) showed that the older adults show semantic priming to even a slightly greater extent than younger adults
In other words, they are even faster to respond to related versus unrelated words compared to younger adults, even if they are slower overall
Semantic Memory (Binder & Desai, 2011)- which brain areas are involved?
A diffuse network of brain regions underlie semantic memory
These brain areas are shared with other sensory/perception and motor/action areas
Less dependence on areas that decline in older age (e.g., hippocampus)
- From a neuroscientific point of view, there are also areas of the brain that support semantic memory that are not the same areas that overlap with episodic memory There is much less dependence on areas of the brain that underlie episodic memory and are known to decline in older age, such as the hippocampus
How do crystallized abilities (semantic memory, SM) change with age?
SM improves across the lifespan due to acquired education/life experience and age-impaired brain areas being less involved in SM
What is Fluid Intelligence?
Abstract reasoning in novel situations
Episodic Memory (EM)- 1. Recollection (“remember”), 2. Familiarity (“know”)
- Recollection (“Remember”)
Retrieving the specific contextual, associative, perceptual etc. details an event- Familiarity (“Know”)
Memory in the absence of retrieving specific details, e.g., “It just feels familiar”; “It rings a bell”
- Familiarity (“Know”)
One way of testing the contributions of these processes to episodic memory is through the remember/know test
- For example, if I present a series of words for participants to try to remember, I may then test them afterward during a recognition test where I re-present those words amongst entirely new words, and ask them for the words that they recognize as “old”, what is their subjective experience? Do they vividly “remember” studying the word, such that they can retrieve accompanying details (e.g., “I remember thinking about the apple I had for lunch, that apple came after the word king” etc.) or do they just “know” that they studied it, but don’t recall any specific details
Episodic Memory (EM)- False alarms= saying “old” to words that are new
- There are also situations in which they can say “old” to words that were not actually presented (e.g. assume “door” in this example was not presented during the list)
- This would be an example of a false alarm – they falsely recognized a new word as having been presented
Still, they would be asked whether they “remember” or “know” that the word was presented based on their subjective experience
- This would be an example of a false alarm – they falsely recognized a new word as having been presented
Dual Process Theory and Ageing (McCabe et al., 2009)- results
RESULTS
- there is an age-related decline in Remember judgments but no difference in Know judgments for Hits, whereas there is an age-related increase in false remembering in terms of both remember and know judgments.
- This suggests that the decline in episodic memory in older age is SPECIFIC to recollection-based memory – older adults struggle more than younger adults to accurately “remember” information according to its original details - However, the fact that there is no difference between younger and older adults in terms of their correct “know” judgments means that they are just as likely to be accurate as younger adults when it comes to familiarity-based judgments
-This means recollection is deficient in healthy older age, but familiarity is intact
Dual Process Theory and Ageing (Raz et al., 2005) Cerebral Cortex- what explains this distinction between familiarity and recollection in older age? + Study results
Conducted a longitudinal study that investigated the brain regions that reduce in volume in healthy older age vs stay stable or show minimal reduction
- Not just all decline when it comes to the brain – there are select regions like the hippocampus and caudate nucleus that decline in structural integrity, whereas other areas like the entorhinal cortex remain relatively stable
Dual Process Theory and Ageing (Yonelinas et al., 2007) Hippocampus- double dissociation + results
Double dissociation= link between recall and hippocampus vs. entorhinal cortex and recognition
- So, the researchers showed that performance on recall tests was more strongly associated with the structural integrity of the hippocampus, whereas performance on the recognition test was more strongly related to the volume of the entorhinal cortex - This gives us a brain explanation of the recollection/familiarity distinction more generally, but also tells us specifically why older adults would struggle with recollection compared to familiarity - Put simply or at least biologically, the volume of the areas of the brain responsible for recollection (i.e., the hippocampus) is more likely to decline compared to areas of the brain (i.e. entorhinal cortex) supporting familiarity
