New American research shows that pregnancy and child rearing enhance
mental capabilities
Robin McKie, guardian.co.uk, January 15, 2006:
It is a time of sleep deprivation, constant tiredness and a regular
inability to carry out even the simplest task. But now scientists have
discovered - after experimenting on the California deer mouse, laboratory
rats, and humans - that pregnancy also confers startling benefits: it
actually boosts brainpower.
During pregnancy, learning and memory skills improve dramatically, say
researchers, reversing the popular myth that it is a time of dumbing down.
Key brain areas also alter in size; changes that can persist for decades.
Far from transforming mothers into weakened emotional wrecks who lose car
keys and drop in IQ, it turns out having children makes them cleverer. It's
just hard to spot thanks to all that lost sleep.
'Many benefits seem to emerge from motherhood, as the maternal brain
rises to the reproductive challenge,' says Professor Craig Kinsley, of
Richmond University, and Professor Kelly Lambert, of Randolph-Macon College,
both in Virginia, writing in the latest Scientific American. 'In other
words, when the going gets tough, the brain gets going.'
Their paper reveals that the brain-boosting potential of parenthood
includes enhanced sensory abilities just after childbirth, allowing women to
recognise their infants by faint smells and sounds. It also reports that
women who have children in their forties are four times more likely to
survive to 100 than women who gave birth earlier. Pregnancy enhances women's
brains just when the memory decline of middle age normally kicks in, say
researchers, leading to better mental health and longevity.
Underlying these changes are two key processes. The first involves the
hormonal fluctuations of pregnancy, birth and lactation, which remodel the
brain, increasing the size of neurons in some regions. Women become vigilant
and alert - and the benefits appear to be long-lasting, say Kinsley and
Lambert.
Secondly, rearing a child is so challenging it stimulates brain activity.
Having a baby is 'a revolution for the brain', says Dr Michael Merzenich of
the University of California in San Francisco. The brain creates cells that
thrive the more they are used and the emotional, novel experiences of
childraising provide the most stimulating use of all.
Further support for this idea is provided by Katherine Ellison in her
book, The Mommy Brain, published last year in the United States and
scheduled for release in the UK in April. As Ellison points out: 'There's no
other time in a woman's life when she needs to be quite as smart as when she
is looking after young children.'
In other words, getting a cerebral lift in pregnancy makes evolutionary
sense and evidence can be seen throughout the animal kingdom, Lambert told
The Observer. 'We just didn't look for the evidence before,' she said.
In one experiment, scientists compared the behaviour of virgin female
rats with those with litters. The rats were placed in enclosures containing
a cricket - a tasty rat snack - hidden under wood chips. 'The virgins took
nearly 270 seconds to find the cricket and eat it, compared with slightly
more than 50 seconds for mother rats,' Lambert said.
Kinsley and Lambert say the phenomenon could have been a key driver in
the evolution of all mammals. Instead of laying eggs and walking off like
reptiles, mammals defend their young. Creatures that were most vigilant at
this time would have fared better and lived longer.
The idea may seem startling because a dimming of brain power is still
viewed as a side effect of motherhood. 'It does seem counter-intuitive,'
added Lambert. 'We just haven't noticed it because these boosts are masked
by sleep deprivation. It wasn't until I had a baby that I realised what is
involved in having a child and how organised a female has to be. It makes
sense for her body to boost her mental capacities.'
But if mothers get a boost from parenthood, is the same true for fathers?
Lambert says yes, but to a more limited extent. 'A man won't get a hormone
boost, but if he is an involved father he will gain through sharing the
challenging experience of childraising.'
This idea is backed by Lambert's studies of the California deer mouse,
the male of which shares equally in childrearing tasks. Experienced fathers
were found to do better than inexperienced males in experiments that tested
their ability to navigate mazes and find food.
I'm more alert mentally now'
Aine Ropke was born on 26 September to Polly Thompson and Stuart Ropke.
'In the months leading up to Aine's birth, I had been doing some serious
multi-tasking,' said Polly. I was juggling the major renovation of our house
while getting everything ready for the baby's arrival - which is a big deal
when it's your first. At the same time I started a new, stressful and
demanding job.
When I gave birth, however, I thought my brain had turned to mush. I was
enormously happy, but at the same time I was exhausted and distracted. As
the tiredness and stress dropped away, the mists in my head began to clear.
Suddenly everything became sharper again and instead of being unable to
remember anything, I was plotting, planning and organising just as
efficiently as I did before. I think I'm even more mentally alert now than
before Aine arrived, because I have to be.'