The question of where insights come from has become a hot topic in neuroscience, despite t

he fact that they are not easy to induce experimentally in a laboratory. Dr. Bhattacharya and Dr. Sheth have taken a creative approach. They have selected some brain-teasing but practical problems in the hope that these would get closer to mimicking real insight: To qualify, a puzzle had to be simple, not too widely known and without a methodical solution. The researchers then asked 18 young adults to try to solve these problems while their brainwaves were monitored using an electroencephalograph (EEG).

A typical brain-teaser went like this. There are three light switches on the ground-floor wall of a three-storey house. Two of the switches do nothing, but one of them controls a bulb on the second floor. When you begin, the bulb is off. You can only make one visit to the second floor. How do you work out which switch is the one that controls the light？

This problem, or one equivalent to it, was presented on a computer screen to a volunteer when that volunteer pressed a button. The electrical activity of the volunteer’s brain (his brainwave pattern) was recorded by the EEG from the button’s press. Each volunteer was given 30 seconds to read the puzzle and another 60 to 90 seconds to solve it.

Some people worked it out; others did not. The significant point, though, was that the EEG predicted who would fall where. Those volunteers who went on to have an insight (in this case that on their one and only visit to the second floor they could use not just the light hut the heat produced by a bulb as evidence of an active switch) had had different brainwave activity from those who never got it. In the right frontal cortex, a part of the brain associated with shifting mental states, there was an increase in high-frequency gamma waves (those with 47-48 cycles a second). Moreover, the difference was noticeable up to eight seconds before the volunteer realised he had found the solution. Dr. Sheth thinks this may he capturing the “transformational thought” in action, before the brain’s “owner” is consciously aware of it.

This finding poses fascinating questions about how the brain really works. Conscious thought, it seems, does not solve problems. Instead, unconscious processing happens in the background and only delivers the answer to consciousness once it has been arrived at. Food for further thought, indeed.

Which kind of problems can he used in Dr. Bhattacharya and Dr. Sheth’s research？

A．Theoretical brain-teasing problems,

B．Simple but rarely known problems.

C．Puzzling hut realistic problems.

D．Simple but theoretical problems.