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Featured Topic
WHAT STRESSES PUPILS OUT
A maths paper, an unannounced biology test or the oral A-level exam have caused palpitations in quite a few
pupils. Some stress in school is a normal occurrence and doesn't do any harm. If it persists, however, it can affect
the pupils’ health. Dr Nina Minkley from the work group Behavioural Biology and Biology Didactics investigates
what kind of situations cause the stress hormone level to increase in pupils.
“I believe stress has a much greater impact than we have suspected," says Nina Minkley. “My main objective is to
find out what stresses pupils at school and to use the results to develop didactic methods of stress prevention.”
Stress studies have been conducted for several decades. In order to determine how stressed out pupils feel in
specific situations, scientists typically make use of questionnaires. Nina Minkley has chosen a different approach. She
has additionally recorded the fluctuation in concentration of the stress hormone cortisol in saliva. Earlier studies had
shown that subjective perception does not correspond with actual cortisol levels. An individual may feel stressed and
yet have a low cortisol level, and vice versa. Does that mean that it is problematic to feel stressed? Or is releasing
stress hormones problematic?
“Needless to say pupils should not feel excessively stressed out. But we wouldn’t want people to feel good, and
yet present a raised cortisol level throughout, either,” says the researcher. The hormone affects a number of
physiological processes; it raises, for example, blood pressure and weakens the immune system. In the long run, it
may lead to chronic diseases.
For her studies, Nina Minkley developed a stress test which raises the pupils’ cortisol level. “When I worked as a
teacher, I was always under the impression that pupils find those tasks particularly difficult that require problemsolving skills,” she explains. Which are accordingly particularly stressful?
Minkley has created two ten-minute tests. One featured only reproductive tasks, where pupils had to retrieve
previously memorised knowledge. Another featured exclusively complex tasks, for which the participants had to
attempt to develop a solution on their own or adapt existing knowledge in a new situation. Twenty-five sixth-form
biology pupils took part in each test. They attended a molecular-biology course at the RUB Experimental Laboratory
for Young People. The test questions pertained to subjects that they had learned in that course immediately prior to
the test.
Before and after the test, Nina Minkley collected saliva samples from all participants. She used them to
determine to what extent the cortisol level changed due to the test. Contrary to expectations, the cortisol level
increased through reproductive tasks more strongly than through complex ones. “I was surprised,” concludes
Minkley. “And it was also surprising how significantly the cortisol concentration increased, considering that it was
only a ten-minute test.”
Following the same principle, she subsequently assessed to what extent the subjective feeling of stress and
cortisol concentration correlated with capacity self-assessment, i.e. the impression an individual has of their own
skills. In order to record capacity self-assessment for the school subject biology, pupils rated a number of
statements, e.g. “I don’t find biology difficult” or “I often know the answers in biology”. Subsequently, the
participants underwent a test. Before and after the test, they provided saliva samples for cortisol analysis.
The poorer the pupils rated their biological knowledge, the higher the increase of stress hormone in their saliva
due to the test. The subjective statement of how stressed the pupils felt, however, was not related to their capacity
self-assessment. Just like in other studies, it was yet again demonstrated that the cortisol concentration and
perceived stress are two separate dimensions.
Cortisol can be detected not only in the short term in saliva, but it has also been shown to be present in hair,
where it is retained over the period of several months. Because hair grows continuously one centimetre per month,
it can be determined when, exactly, cortisol was deposited in which segment. Minkley used this approach to
compare female pupils in the double-cohort year, who completed their school leaving examination after eight (G8)
resp. nine years (G9). Four weeks after the examination, she collected a strand of hair from them and analysed a
four-centimetre long segment, which she cut in half. One half was from the pre-exam phase, the other from the
exam phase.
In both the G8 and the G9 group, the hair collected during the pre-exam phase contained less cortisol than that
hair collected during the exam phase. However, no significant differences between the groups were determined.
That means that, according to statistical analysis, pupils who have completed their secondary education after eight
years had not produced more stress hormones than those who had had one year more time.
Does that mean the debate regarding G8/G9 had been pointless? There is no conclusive answer to this question.
As far as absolute figures are concerned, the G8 pupils presented higher cortisol levels. But the difference was not
significant enough to be proven in statistical analysis. There may be two reasons for this: either there is no difference
between G8 and G9, or there isn’t anymore, as both cohorts had had lessons together for two years by the time the
test was performed. “We might have discovered differences in the lower or middle grade. In the lower and middle
grade, the pupils were not schooled together, and the G8 pupils had to prepare for sixth form within a shorter space
of time,” says Minkley. This question will remain unanswered, because the double-cohort year is over, and therefore
additional studies cannot be conducted. Nina Minkley, however, will search in other places for possibilities of
detecting stress triggers at school and to reduce the stress levels experienced by pupils.
Julia Weiler
FROM TERMITES TO PUPILS
Dr Nina Minkley’s career as a researcher took off with termite experiments. After attaining her university
qualifications as a biology and pedagogy teacher, she investigated those animals’ behaviour in her first state
examination and her PhD thesis. “I still had the option to become a teacher,” she explains, “and a position opened at
my dream school.” She took the chance and worked as a teacher for five years. During all this time, she stayed in
touch with her doctoral supervisor, Prof Wolfgang Kirchner, and Nina Minkley gave courses for students pursuing a
teaching degree at RUB. In 2010, the university advertised for a professional with school experience for didactic
research. Minkley met the requirements perfectly, and she was interested in the position because of her personal
experience as a biology teacher.
“Among pupils, biology has the reputation of being the easiest natural science discipline, but there are still many
who say ‘I’ve never been any good in biology’, and who thus stand in their own way,” as Minkley relates her school
experience. “You develop an intuition for such situations, but they also roused the researcher in me. I wished to
research into the causes systematically.” After the first projects, she now wants to focus on specific questions.
Currently, she is investigating in what way conducting experiments in groups or individually in biology courses affects
stress hormones and stress perception. Moreover, she wishes to assess if dealing with chemical structural formulae
or with molecular graphics puts the pupils particularly strongly under pressure, and to develop a tool to counteract
this process.
Julia Weiler