Health
What happens to our cognitive abilities as we age?
Traditionally it is thought that age leads to a steady deterioration of brain function, but new research in Topics in Cognitive Science argues that older brains may take longer to process ever increasing amounts of knowledge, and this has often been misidentified as declining capacity.
The study, led by Dr. Michael Ramscar of the University of Tuebingen, takes a critical look at the measures that are usually thought to show that our cognitive abilities decline across adulthood.
Instead of finding evidence of decline, the team discovered that most standard cognitive measures are flawed, confusing increased knowledge for declining capacity.
Dr. Ramscar's team used computers, programmed to act as though they were humans, to read a certain amount each day, learning new things along the way.
When the researchers let a computer “read” a limited amount, its performance on cognitive tests resembled that of a young adult.
However, if the same computer was exposed data which represented a lifetime of experiences its performance looked like that of an older adult.
Often it was slower, not because its processing capacity had declined, but because increased “experience” had caused the computer's database to grow, giving it more data to process, and that processing takes time.
“What does this finding mean for our understanding of our ageing minds, for example older adults' increased difficulties with word recall? These are traditionally thought to reveal how our memory for words deteriorates with age, but Big Data adds a twist to this idea,” said Dr. Ramscar. “Technology now allows researchers to make quantitative estimates about the number of words an adult can be expected to learn across a lifetime, enabling the team to separate the challenge that increasing knowledge poses to memory from the actual performance of memory itself.”
“Imagine someone who knows two people's birthdays and can recall them almost perfectly. Would you really want to say that person has a better memory than a person who knows the birthdays of 2000 people, but can 'only' match the right person to the right birthday nine times out of ten?” asks Ramscar.
“It is time we rethink what we mean by the aging mind before our false assumptions result in decisions and policies that marginalize the old or waste precious public resources to remediate problems that do not exist,” said Topics in Cognitive Science, Editors Wayne Gray and Thomas Hills.
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As the abundance of genetically modified (GM) foods continues to grow, so does the demand for monitoring and labeling them.
The genes of GM plants used for food are tweaked to make them more healthful or pest-resistant, but some consumers are wary of such changes.
To help inform shoppers and enforce regulations, scientists are reporting in ACS' journal Analytical Chemistry the first comprehensive method to detect genetic modifications in one convenient, accurate test.
Li-Tao Yang, Sheng-Ce Tao and colleagues note that by the end of 2012, farmers were growing GM crops on more than 420 million acres of land across 28 countries. That's 100 times more than when commercialization began in 1996.
But doubts persist about the potential effects on the environment and human health of these biotech crops, created by changing the plants' genes to make them more healthful or more able to resist pests. In response, policymakers, particularly in Europe, have instituted regulations to monitor GM products.
Although researchers have come up with many ways to detect genetic modification in crops, no single test existed to do a comprehensive scan, which is where Yang and Tao come in.
They developed a test they call “MACRO,” which stands for: multiplex amplification on a chip with readout on an oligo microarray.
It combines two well-known genetic methods to flag about 97 percent of the known commercialized modifications, almost twice as many as other tests.
It also can be easily expanded to include future genetically modified crops.
The authors acknowledge funding from the National Transgenic Plant Special Fund, the Program for New Century Excellent Talents in University, the State Key Development Program for Basic Research of China, the National High Technology Research and Development Program of China, the National Natural Science Foundation of China.
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