Microsoft supremo Bill Gates wants to fit school students with mood bracelets¹ to measure how interested they are in their lessons.

微软创始人比尔·盖茨正研制一款适用于学生的“情绪手镯”，来检测他们对上课内容有多感兴趣。

The Bill and Melinda Gates foundation is spending $1.1 million (£700,000) testing galvanic（电流的） skin response bracelets to see if they can measure whether students find their teachers engaging.

The move is part of the billionaire's mission to evaluate and improve the quality of teachers, which has already included controversial initiatives such as fitting classrooms with video cameras.

The bracelets measure how well the skin conducts electricity, which varies with its moisture level.

Sweat glands² are controlled by the nervous system so skin conductance can be used as an indication of emotional response.

Some US teachers and commentators³ have been less than impressed with the plan.

'Why would anybody spent money on this when some school systems can't afford to pay their electric bills?' Education blogger Valerie Strauss wrote in the Washington Post.

'The obsession⁴ with measurement in data and school reform has reached nutty new heights.'

Teacher Anthony Cody, writing in Education Week, commented: 'The wonderful thing about having human beings as teachers is that we are naturally empathetic（移情作用的） . We do not need galvanic skin sensors⁵ to detect when our students are drowsy⁶ or disinterested⁷ -- we can look around the room in an instant and know!’

Others have pointed⁸ out limitations with the bracelets, including that they are not able to tell whether a student was responding to their teacher or something a friend whispers in their ear.

The bracelets are also so far unable to distinguish whether a heightened response is due to excitement or anxiety, and whether a drop in response is due to relaxation⁹ or boredom¹⁰.

The amount Bill Gates has spent on evaluating the bracelets is already more than $1.1 million.

Clemson University has been given almost $500,000 (£320,000) to run a pilot study 'which will determine the feasibility and utility of using such devices regularly in schools with students and teachers.'

The National Center on Time and Learning was given more than $620,000 ($400,000) to assess the effectiveness of the bracelets by comparing them with MRI scans, and work out a scale that would pinpoint¹¹ how engaged a student was in lessons.