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Is Age-Related Mental Decline Not As Bad As We Think?

2014 February 5
by Richard N. Landers

ResearchBlogging.orgIt’s well-supported in psychology that fluid intelligence (i.e. a person’s ability to solve unique, unfamiliar problems or remember large amounts of unfamiliar information, or otherwise flex their mental muscles) decreases with age.  There are several theories as to why – perhaps our brains become less efficient over time as our neurons age, or perhaps we simply exercise our brains less as we get older, resulting in a sort of muscular atrophy).  But a new paper by Ramscar, Hendrix, Shaoul, Milin and Baayen[1] in Topics in Cognitive Science, described in an article published by the New York Times, provides a new theory: as our brains store more information, it may become more difficult to retrieve memories.  This contention is based on information theory, which explores how information processing occurs in computing systems (e.g., what is the most efficient way to seek specific information given a database of general information?).  As we get older, the theory states, we have more memories to sort through, which causes us to perform more poorly on cognitive measures.

Several statements in the New York Times article on this topic intrigued me.  

  1. The title: “The Older Mind May Just Be a Fuller Mind.”
  2. A notable assertion: “The new report will very likely add to a growing skepticism about how steep age-related decline really is. It goes without saying that many people remain disarmingly razor-witted well into their 90s; yet doubts about the average extent of the decline are rooted not in individual differences but in study methodology.”
  3. The conclusion: “It’s not that you’re slow. It’s that you know so much.”

The title is tentative, the next statement is an anecdote (several people does not a theory prove), and the last is just intended to be memorable.  Yet these statements, among others in the article, are provocative, leaving the reader with just enough information in order to maximize the punch of that final pithy conclusion.  But is it a valid conclusion?

For that, I needed to turn to the original research article. This was a bit of an exercise, because the article is presumably written with an audience of information scientists in mind, and I am not an information scientist. But from my reading, I believe that I was able to decode what they did.  The basic premise was that the researchers conducted a series of simulations (i.e. not using human participants) on developed vocabulary.  In the first simulation, the researchers constructed a database of words of varying complexity.  They then selected words based upon a simulated 20 people learning words over their lifespans, plotting the number of words learned at each age.

This is the first peculiar decision in this study if the goal is to generalize to humans, because it assumes that people add new words to their vocabulary at a predictable, curved rate.  In one illustrative graph (p. 10), the mean vocabulary across the 20 individuals was plotted as a function of age – however, age was defined as the number of words that a person had been exposed to.  The valid conclusion from this figure appears to be that exposure to a greater number of words leads to a larger vocabulary.  So the actual finding is not surprising, but the use of the word “age” to describe the effect is a bit strange.  For this to be a valid in describing age, our reading habits would need to be something like: I read random books with random words in them and am exposed to new words on a regular basis.  I suspect reality is not quite so random.

The researchers next made some assumptions about how many words people were exposed to and the growth rates of vocabulary.  They assumed that adults read 85 words/min, 45 min/day, 100 days/year.  They also assumed that adults encountered new words not in their vocabulary at the rates established in their prior simulation.  Given those assumptions, they created algorithms to read from lists of words at that rate for the equivalent of a 21-year old (1,500,000 words) and a 70-year old (29,000,000 words).  They then simulated how long (relative to each other) retrieving words would be from each of those lists, finding that the 70-year old would take longer to browse through her memory than the 21-year old would.

These do not seem like wise assumptions to me.  I would hazard a guess that I learn a handful of new words in any given year, and my reading is also restricted to things I’m interested in on the Internet (where the overall reading level is not terribly high) and in psychology journals.  I strongly doubt people reading newspapers and magazines in their free time (the primary sources of reading for our current seniors) encountered new words at a predictable, consistent rate – and I would guess that the new word encounter rate of a non-academic is somewhat lower than mine.  More accessible metrics (e.g. new words/year) are not presented in the article, so I don’t have any way to convert the numbers reported in the article into more understandable metrics.  Again, this assumes that people read random sources with random words in them, constantly exposing themselves to new vocabulary, regardless of age.  It also assumes that the brain works perfectly like a computer algorithm; yet we know that the human brain relies heavily on heuristics/shortcuts and makes a lot of mistakes.  This does not match up the researchers’ model.

There were also a few writing peculiarities.  Take this, from p. 16:

To ensure older adults’ greater sensitivity to low-frequency words was not specific to this particular data set, a second empirical set of data was analyzed in the same way (Yap, Balota, Sibley, & Ratcliff, 2011; Fig. 4). All of the effects reported in the first analysis replicated successfully.

This is the entire discussion of this apparently independent follow-up study – no explaining anything they did in that follow-up study, no reporting of any statistics actually conducting the “comparisons”, no defining a “successful replication”, and no listing the effects that they tested.  The entire “methods” and “results” sections associated with this statement were in fact a single figure.  Maybe that’s normal in cognitive science, but it would never fly in a decent psychology journal.  We have no way to know what they did, why they did it, what was replicated, what went wrong, etc.  The ability to replicate from a write-up is absolutely required for good science, and this element is missing from this part of the paper.  That’s not catastrophic – since this replication isn’t really necessary to make the point they were making – but it adds yet another “that’s weird” to my tally as I read through.

So despite being based upon faulty assumptions about human learning as well as being limited entirely to the growth of vocabulary over the life-span, the second simulation described above seems to be the basis for the NYT article conclusion that memory in general does not decline with age.  This conclusion is not justified.  Contrary to the NYT statement, I am no more skeptical of age-related decline than I was before reading either the NYT piece or the original research article.

To me, both the NYT and original article demonstrate only one thing clearly: when applying information processing theory to understanding human cognition, one must be careful to remember the “human”.

  1. Ramscar, M., Hendrix, P., Shaoul, C., Milin, P., & Baayen, H. (2014). The myth of cognitive decline: Non-linear dynamics of lifelong learning Topics in Cognitive Science, 6, 5-42 : 10.1111/tops.12078 []

Using Links And Writing About Morality Increase Perceived Credibility

2014 January 29
by Richard N. Landers

ResearchBlogging.orgIn an upcoming issue of the Journal of Computer-Mediated Communication, Borah[1] conducted two experiments on 550 people to identify the interactive effect between story framing and embedded links on people reading about politically charged issues – in this case, gay marriage and immigration.  The researchers found that a website with critical analysis of political strategy related to gay marriage (or immigration) is viewed as less trustworthy than a website describing the morality of gay marriage (or immigration), even when the factual information reported by those two websites is the same.  If you’re running a political website, it seems that emotional appeals about the battle for America’s moral center are more likely to lead to increased readership than thoughtful commentary on political maneuvering.  Or in other words, in-depth and critical reporting about politics appears to be the enemy of readership, as sad as that sounds.

When journalists focus their writing upon the morality of political issues (called a “values frame”), readers view the presence of external links as credibility-boosting.  When journalists report the same information but focus upon political strategy instead (called a “strategy frame”), readers react cynically and find the article less trustworthy regardless of how many external links are used.  The precise nature of this relationship will be clearer with an example:

  1. Katie the Reporter writes about how gay marriage is saving/destroying America’s soul (values condition).  She doesn’t include any links to additional content (no hyperlinks condition).  This is the baseline.
  2. Sue the Reporter writes about how gay marriage is saving/destroying America’s soul (values condition).  Throughout her article, she includes links to other articles that support her points (hyperlinks condition).  Readers trust Sue’s article more than they trust Katie’s article.
  3. John the Reporter writes about how various politicians have been using gay marriage to get re-elected or gain political klout (strategy condition).  The same factual information about the gay marriage debate is contained in John’s article as is contained in Katie’s and Sue’s articles.  Whether John includes links or not, readers trust John’s article less than either Katie’s or Sue’s articles.


The proposed reasons for this effect are fascinating:

  1. When you read about a moral outrage that you agree with, you are inclined to believe it because it confirms your opinion (this is called confirmation bias).  This increases the credibility of the site you’re reading.
  2. When you read about a moral outrage that you disagree with, you understand the opposition’s viewpoint even if you don’t agree with it.  This increases the credibility of the site you’re reading.
  3. When you read about how politicians are using what you consider to be a moral issue to further their careers, you become cynical about those politicians.  By association, you also become cynical about the website you’re reading, which decreases its credibility.

The researcher also found that the mere presence of hyperlinks increases readers’ willingness to seek out more information and actual information-seeking behaviors, although framing did not affect either of these two outcomes.

  1. Borah, P. (2014). The hyperlinked world: A look at how the interactions of news frames and hyperlinks influence news credibility and willingness to seek information Journal of Computer-Mediated Communication []

The Privacy Paradox: Why People Who Complain About Privacy Also Overshare

2014 January 23
by Richard N. Landers

ResearchBlogging.orgIn an upcoming issue of the Journal of Computer-Mediated Communication, Taddicken[1] explores a phenomenon called the privacy paradox, a term that describes how social media users report that they are concerned about their privacy but do very little to actively protect it. In this study, 2739 German Internet users were surveyed to help identify why people overshare despite such concerns. In her study, roughly 30% of social media users reported sharing personal photos without any access restrictions, and roughly 17% reported sharing their thoughts, experiences, thoughts, feelings, concerns and fears to the wide open Internet.

Two personality traits were found to drive sharing: a person’s desire to talk about themselves regardless of situation, followed by the degree to which people found social media to be relevant to their personal social lives.  So as it turns out, many people do want it both ways: they want to enrich their social lives by talking about themselves online to anyone who will listen, but they don’t want this information to be read by just anyone.  Apparently their desire to be social is simply stronger than their desire to protect their privacy.  The important implication here is that it implies simply teaching people about privacy and how to safeguard their information isn’t going to work; the desire to share with others is too strong.

Privacy concerns did affect sharing, but only indirectly.  Greater privacy concerns were weakly associated with lower willingness to self-disclose, and willingness to self-disclose was strongly positively associated with actual sharing.  Greater privacy concerns were also weakly associated with smaller number of joined social media platforms, and the number of social media platforms joined was moderately associated with less self-disclosure.  So this brings what appears to me to be a new paradox: people more concerned about privacy join fewer sites, but those that join fewer sites tend to share more on those sites.

Figure 2 from Taddicken (2014)

The research also identified a difference between two types of personal information: factual (last name, birth date, professional, and postal address) and “sensitive” (photos, experiences, thoughts, feelings, concerns and fears). Roughly 90% of respondents provided first names and email addresses on social media, so given the lack of variation, these were not included in further analyses. Other factual information was shared at least once on social media by 54.6% of respondents, although only 10% did so without restricting who could see it.

Sensitive information was a little more complicated. In general, fewer individuals share sensitive information than basic factual information (first names and email addresses), but more individuals share sensitive information than private factual information. So the specific nature of sharing was a little complicated:

  • Roughly 80% of respondents had shared their last name, birth date and profession at least once on social media.  Of those sharing at least once, about 63% restricted access to it.
  • Roughly 50% of respondents had shared their postal address, and among those sharing at least once, about 90% restricted access to it.
  • Roughly 60% of respondents had shared photos, experiences, and thoughts at least once.  Of those sharing such things, about 60% restricted access to it.
  • Roughly 40% of respondents had shared their feelings, concerns and fears at least once.  Of those sharing such things, about 70% restricted access to it.

Overall, this study provides an interesting look into some personality drivers of self-disclosure on the Internet.  It is not, however, an exhaustive model.  The model presented here would fit just as well in several other configurations, which would alter the path coefficients obtained – for example, joining lots of websites might make users less concerned about privacy, which might in turn drive self-disclosure.  Further research will need to explore these components experimentally to get to the heart of causation in this matter.

  1. Taddicken, M. (2014). The ‘privacy paradox’ in the social web: The impact of privacy concerns, individual characteristics, and the perceived social relevance on different forms of self-disclosure Journal of Computer-Mediated Communication, 19, 248-273 : 10.1111/jcc4.12052 []