【单选题】

Could a simple memory workout make you smarterAn intriguing new study by researchers at the University of Michigan suggests it can—a finding that adds a wrinkle to the prevailing notion that IQ is largely fixed by genes.

The study involved 62 elementary-and middle-school children from southeast Michigan who were randomly assigned to train on one of two video game-like computer tasks. One group performed a mental training exercise aimed at improving working memory, the ability to hold and retrieve information in the short term. The other group practiced general knowledge and vocabulary skills.Both groups trained for one month, five times a week for 15 minutes per session.
At the end of the intervention, many of the kids who had engaged in the working-memory task had boosted a key attribute of their intelligence—by some five points. Specifically, they improved their performance on tests of so-called fluid intelligence, the ability t9 solve new problems and reason abstractly.
Researchers have long debated whether fluid intelligence—considered a significant predictor of educational success—could be reliably improved by training. Fluid intelligence is thought to be independent of learning, experience or education and, therefore, mainly governed by genes.By contrast, the other component of overall intelligence, crystallized intelligence, which involves the acquisition of discrete bits of knowledge, improves with learning.
The Michigan researchers found that kids had not only enhanced their fluid intelligence after training on the working-memory tasks, but that they also maintained the gains for three months after training endeD、
There were several limitations to the findings, however. To start, the size of children’s improvements was inconsistent. It’s possible that kids who saw greater gains in fluid intelligence were those who started out at lower ability levels and simply had more room to improve. Further, not every child improveD、The authors suggested that students who failed to benefit from the working-memory training found the task too difficult or boring, and became frustrated and disengageD、Indeed, the training task is a chore, even when dressed up in a video game. The job of the child is to press the space bar whenever the character returns to a spot where it has previously been, and to ignore the other irrelevant locations.As the children advance in the task, these locations move further back in time, forcing them to sort through an increasing amount of information.
Perhaps more importantly, it’s not clear whether higher scores on tests of fluid intelligence have any real-world significance: whether they naturally translate to better grades or improvements in other abilities-or for that matter whether they predict better jobs or more life success down the line. For now, the Michigan researchers are planning to investigate whether the same training task could benefit children with deficits in working memory and attention. Lead author Susanne Jaeggi and her team are also working on an intervention that can be easily implemented in schools and other educational settings.
Fluid intelligence is different from crystallized intelligence in that
A、the former is a capacity independent of acquired knowledge.
B．the former refers to the ability to solve abstract problems.
C．the former cannot be improved even with proper training.
D．the former serves as the genetic basis for the latter.