The idea is not without its critics, however. One of the main objections is the implication that because it is said to be genetically inherited, a person cannot significantly increase their level of general intelligence. However, clearly we can get better at reasoning tasks.
Later researchers such as Raymond Cattell suggested that 'g' should be subdivided into two parts, crystalised intelligence or Gc and fluid intelligence or Gf. Gc is a cumulative set of skills and strategies that can increase through life as you get better at tasks, while Gc is a more flexible ability level for novel tasks. Gc retains the original idea of intelligence as innate, and researchers have tended to assume that it is fixed from early adulthood onwards.
This great blog post by Andrea Kuszewski in Scientific American provides an overview of more recent ideas about fluid intelligence, backed up by research findings which go against the idea that it is fixed. In brief summary, for Gf to be increased you should:
- Seek novelty ("it is no coincidence that geniuses like Einstein were skilled in multiple areas"). This stimulates the mind.
- Challenge yourself. Work hard at something until you've mastered it - similar to the last point, getting really good at one thing will be of less benefit.
- Think creatively. Learning to think creatively not only makes you better at what you are studying, but it makes you better at other things too. Kuszewski refers to the work of Robert Sternberg (see previous blog post).
- Do things the hard way. It is counterintuitive - as humans we so often tend to choose the easy path - but taking shortcuts and relying on tools means we are not challenging ourselves and therefore not improving.
- Network - use social networking to stimulate the mind and expose yourself to new challenges.
I thought these were really helpful and thought provoking. There was some quality research evidence, although evidence for the last two points was more anecdotal. Also, the first two points seemed rather similar. Still, it was enough for me to want to share it with my students, who were blown away!
One of the comments asks if there is not a limit to how much it can be increased, and if so, is that not the true limit to Gf? I would suggest that there is not a limit, but that like with so many abilities, improvements will get increasingly arduous and time-consuming to obtain, and the benefits will diminish, leading to a practical rather than theoretical limit.
It will also depend greatly on an individual's motivation to improve.