Featured Research

from universities, journals, and other organizations

New study reconciles conflicting data on mental aging

Date:
September 13, 2010
Source:
American Psychological Association
Summary:
A new look at tests of mental aging reveals a good news-bad news situation. The bad news is all mental abilities appear to decline with age, to varying degrees. The good news is the drops are not as steep as some research showed, according to a new study.

A new look at tests of mental aging reveals a good news-bad news situation. The bad news is all mental abilities appear to decline with age, to varying degrees. The good news is the drops are not as steep as some research showed, according to a study published by the American Psychological Association.

Related Articles


"There is now convincing evidence that even vocabulary knowledge and what's called crystallized intelligence decline at older ages," said study author Timothy Salthouse, PhD.

Longitudinal test scores look good in part because repeat test-takers grow familiar with tests or testing strategies, said the University of Virginia psychologist. Factoring out these "practice effects" showed a truer picture of actual mental aging, according to Salthouse.

Still, the declines, although pervasive, are smaller than thought, according to the report in the July issue of Neuropsychology. That finding contradicts data gathered by the other major research approach to aging, cross-sectional studies, which compare the performance of different age groups at the same time.

With both methods subject to bias, "It remains important to recognize the limitations of each type of study design when interpreting results," Salthouse said.

To learn what really happens as people age, Salthouse tackled how different research methods have led to different findings. Cross-sectional studies that compared the abilities of younger and older adults showed big drops in key areas. Longitudinal studies suggested that, until about age 60, abilities are stable or even improve. Which type of study, if either, was right?

To find out, Salthouse analyzed data on five key cognitive abilities from the longitudinal Virginia Cognitive Aging Project. Scores were available for 1,616 adults age 18 to more than 80 on tests of reasoning, spatial visualization, episodic memory, perceptual speed and vocabulary. The data were collected over an average test-retest interval of two-and-a-half years.

First, Salthouse sorted participants into age brackets by decade, each with well more than 100 participants, except for the 80-89 bracket, with 87 participants. Second, he estimated the size of practice effects by comparing scores earned on the second test by the longitudinal participants with scores on a first test by another group of participants. He also used statistical methods to adjust for the chance that weaker performers dropped out between the first and second tests.

Practice effects were evident across the board, allowing test-takers to score higher the second time around not because they truly were more able, but because they knew the test -- an unavoidable byproduct of repeated testing. Although the numbers varied by ability and age, practice effects were found to be as large as or larger than the annual cross-sectional differences.

Numbers in hand, Salthouse removed the practice-related "bonus points." Stripping them out generated a new set of cognitive scores that could be expected to reflect more accurately normal mental aging in healthy adults.

With practice effects taken into account, the age trends in the longitudinal data became more similar to results from cross-sectional studies in the places where they had diverged. The different methods now agreed on the downward direction of change. However, the increments were smaller. In other words, the mental abilities of younger adults still rose over time, but not nearly as much. And the mental abilities of older adults still fell over time, but not quite as much.

Knowing how practice effects, selective attrition and actual maturation affect how people change over time will put psychologists in a better position "to evaluate true age changes, and how they might relate to late-life pathology and everyday functioning," Salthouse said.

Salthouse also found that practice effects played a bigger role in younger than older adults, possibly because younger people learn better. "Longitudinal comparisons in people of different ages may be even more complicated because the amount of longitudinal change may be partially determined by the individual's learning ability at a given age," he noted.

Salthouse is a fellow of the American Psychological Association and other scientific associations, and a past winner of the APA's William James Award. This study was supported by the National Institute on Aging.


Story Source:

The above story is based on materials provided by American Psychological Association. Note: Materials may be edited for content and length.


Journal Reference:

  1. Timothy A. Salthouse. Influence of age on practice effects in longitudinal neurocognitive change.. Neuropsychology, 2010; 24 (5): 563 DOI: 10.1037/a0019026

Cite This Page:

American Psychological Association. "New study reconciles conflicting data on mental aging." ScienceDaily. ScienceDaily, 13 September 2010. <www.sciencedaily.com/releases/2010/09/100913144425.htm>.
American Psychological Association. (2010, September 13). New study reconciles conflicting data on mental aging. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2010/09/100913144425.htm
American Psychological Association. "New study reconciles conflicting data on mental aging." ScienceDaily. www.sciencedaily.com/releases/2010/09/100913144425.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Kids React to Lammily, The Realistic Barbie Alternative

Kids React to Lammily, The Realistic Barbie Alternative

Buzz60 (Nov. 19, 2014) Artist Nickolay Lamm's Kickstarter-funded Lammily doll, based on his 'What Would Barbie Look Like as a Real Woman' project, is finally available to buy. Jen Markham explains how the doll's realistic proportions are going over with a test group of second-graders who are used to the impossible measurements of Barbie dolls. Video provided by Buzz60
Powered by NewsLook.com
Trans-Fat Foods Now Linked To Poor Memory

Trans-Fat Foods Now Linked To Poor Memory

Newsy (Nov. 19, 2014) A study presented at the American Heart Association Scientific Sessions shows a link between diets high in trans fats and decreased memory recall. Video provided by Newsy
Powered by NewsLook.com
Creating Lifelong Love of Science and Math

Creating Lifelong Love of Science and Math

AP (Nov. 18, 2014) Kelly Mathews is a new mom on a mission to get girls interested in science, technology, engineering and math, and it starts with her own daughter. The Girl Scouts are doing their part, too, by promoting S.T.E.M. through badges and activities. (Nov. 18) Video provided by AP
Powered by NewsLook.com
3D Fun Improves Child Therapy in Poland

3D Fun Improves Child Therapy in Poland

Reuters - Innovations Video Online (Nov. 17, 2014) Scientists in Poland are helping children with autism and Down's Syndrome better focus on therapeutic exercises by taking them out of their real world environment and into a specially-designed 3D cave in which their imagination can flourish. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins