HIS mother wept when she was told that he would be placed in the EM3 scheme. He had to bribe his brother not to tell relatives and neighbours about it.

Polytechnic student Marc Tan knows all about the stigma that is attached to the stream for slow learners. 'I was so ashamed,' he told The Straits Times in an e-mail message he wrote after news broke that the current system would be replaced by subject-based banding in 2008.

With the change, he hoped that the labelling and stigmatisation of students will go away. He remembered how streaming affected the way teachers treated the students.

'In primary school, I was quite good in maths, but all the teachers treated us like we were troublemakers and worthless.'

Marc might be exaggerating the extent of derision his teachers dished out. But he is clear about who is responsible for his turnaround: his form teacher in Secondary 1. 'He made me the monitor of the class and said I was better in maths than some of his Express stream students.

'It made all the difference. It was such a confidence boost for me. I worked hard to prove him right,' he said.

Marc took the predictable route for most EM3 pupils, making it to the Normal (Technical) stream in Secondary 1. But where he broke tradition was when he did well enough in Secondary 1 to be transferred to the Normal (Academic) stream in Secondary 2. In Secondary 5, he did well enough in the O-levels to make it to a junior college, but opted for a polytechnic course instead.

Do teachers' expectations of students' performance affect how well their charges do?

Harvard psychologist Robert Rosenthal thought so. His seminal study in the 1960s of young students in what he called 'Oak School' found that when teachers expect students to do well and show intellectual growth, they do.

Likewise, when teachers do not have such expectations, performance and growth are not so encouraged and may in fact be discouraged in a variety of ways.

His conclusions were based on a 'trick' he performed on teachers. After he gave an intelligence test to all the students at the beginning of the school year, he selected 20 per cent of them randomly.

Then he told the teachers that these were students who showed 'unusual potential for intellectual growth' and could be expected to 'bloom' in their academic performance by the end of the year.

Eight months later, he re-tested all the students. Those labelled 'intelligent' showed significantly better results in the new tests than those who were not singled out for attention.

Hence, the Rosenthal Effect: Teachers' expectations about intellectual performance can lead to an 'actual change' in how the students do later.

What happened in between? A self-fulfilling prophecy, going by Professor Rosenthal's observation: 'If you think your students can't achieve very much, are perhaps not too bright, you may be inclined to teach simple stuff, do a lot of drills, read from your lecture notes, give simple assignments calling for simplistic factual answers; that's one important way it can show up.'

Subsequent studies by other researchers appear to back this up. One study involved videotaping the teachers' interaction with students who had been identified as bright.

The tapes showed that teachers smiled and made more eye contact with 'bright' students while other students were treated in a generalised, standard manner.

If the Rosenthal Effect is real, will Singapore's subject- based banding, as opposed to streaming, alter teachers' expectations of their weaker pupils?

That would be wishful thinking. This is how subject-based banding will work for the weakest pupils who are currently streamed into the EM3 course.

All pupils, including those who are lagging behind, will be banded according to their strengths in specific subjects.

For example, a student strong only in mathematics will study it at the standard PSLE level but he will take English and Mother Tongue at the easier foundation level, which covers the basics.

In the current system, he would be studying all three at the foundation level, branding him a weak student.

While the refinements recognise that even the weakest students may have strengths in some areas, let's not run away from the fact that the education system is centred on the belief that children have varying levels of ability and need different curricula and teaching approaches.

This has always been the case, from the days when classes were labelled Primary 1A, B and C. The difference is that the humiliating label EM3 will now be defunct.

Prof Rosenthal himself believed that children have varying abilities. He complained how, at Harvard, some of his colleagues gave out all As.

'Not everybody is going to be a star, a PhD or what have you, that's reality,' he said.

But he strongly believed that all his students can 'learn more than they are learning' and does not prejudge a student's ability.

So he sets high expectations of all his students at Harvard and almost always, all of them deliver.

It would be too much to expect all teachers not to have any kind of expectations when they teach a class.

After all, as one veteran primary school teacher pointed out, the school system itself encourages the differentiation, right from the start in Primary 1.

The weaker pupils are identified through a school readiness test and given special help through the learning support programme.

The question is, are teachers even aware of the sort of impact they have on a child's ability to perform?

Six out of seven teachers polled by The Straits Times had not heard of the Rosenthal Effect.

Researchers at the National Institute of Education have attempted to study teacher perceptions of EM3 students and how these affect their teaching. Once the results are published, they must be scrutinised, to open the eyes of teachers to how their expectations can shape their students' performance.

As the good professor said, it is the moral obligation of a teacher to check his own presumptions.

And if a teacher does not believe in a student's capacity to learn, he should not be that student's teacher.