Feeds

Does thumb-sucking run in families?

Genetic tie up

Security for virtualized datacentres

Also in this week's column:

Does thumb-sucking run in families?

Asked by Michael Woodhams of Palmerston North, New Zealand

Thumb-sucking is a "childhood body-focused behaviour". Others are nail-biting, scratching, hair-pulling, nose-picking, and a few others.

Babies are born with a sucking reflex. In fact, if this reflex is not present from birth, the infant cannot feed and quickly perishes. Babies have a natural urge to suck. They will suck on just about anything that touches their lips. The urge starts to decrease after the age of six months.

About 80 per cent of babies suck their thumbs. Most stop by themselves between the age of three and six years.

There has been no "thumb-sucking gene" found so far. However, recent Japanese research involving 1,131 pairs of twins found that there was a strong genetic influence in finger-sucking behaviour in 66 per cent of male twins and 50 per cent of female twins and in nail-biting behaviour in 50 per cent of both male and female twins.

The study is by Dr S Ooki of the Department of Health Science of Ishikwa Prefectural Nursing University in Kahoku and published in Twins Research and Human Genetics in August 2005.

The observation has long been made that thumb-sucking behaviour seems to run in families. Recently, there has been some research to back this notion. In an Austrian study examining families of children with eating disorders, it was found that children from certain types of families were statistically significantly more likely to exhibit thumb-sucking behaviour.

These families are what the researchers, Dr B.Mangweth and seven colleagues, call "body denying" families. They are families where parents are emotionally cold, disapproving, and show a lack of intimacy towards their children.

Dr Mangweth and colleagues are from the Department of Psychiatry at the Innsbruck University Hospitals. heir study appeared in Psychotherapy and psychosomatics in 2005.

Family factors and the experiences of children have a bearing on thumb-sucking, nail-biting, and a host of other forms of "oral habits". Indeed, a study of abnormal oral habits (for example, biting other people) in the children of war veterans in Iran showed that when children have brutalising experiences, they behave brutally with their bodies - including their mouths.

Dr Y Tassaei and two colleagues from the Shahid Sadoughi University of Medical Sciences and Health Services in Yazd, Iran write in the Journal of Clinical Pediatric Dentistry in 2005 that: "The prevalence rate [of abnormal oral behaviours] was highest in children, whose family members had been both crippled and freed prisoners of war, while the rate was lowest in children whose parents had been only prisoners of war without any lasting physical injury."

Interesting fact

Handedness is determined before you are born. The hand that is preferred when thumb-sucking as a fetus is almost certainly to be the preferred hand after birth. For example, all of 60 right-thumb sucking fetuses turned out to be right-handed in childhood. This was found in a study by Dr P G Hepper and two colleagues from the School of Psychology at Queen's University in Belfast, Northern Ireland, and published in Neuropsychologia in 2005.

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to s.juan@edfac.usyd.edu.au

Security for virtualized datacentres

More from The Register

next story
Boffins say they've got Lithium batteries the wrong way around
Surprises at the nano-scale mean our ideas about how they charge could be all wrong
Thought that last dinosaur was BIG? This one's bloody ENORMOUS
Weighed several adult elephants, contend boffins
Europe prepares to INVADE comet: Rosetta landing site chosen
No word yet on whether backup site is labelled 'K'
City hidden beneath England's Stonehenge had HUMAN ABATTOIR. And a pub
Boozed-up ancients drank beer before tearing corpses apart
'Duck face' selfie in SPAAAACE: Rosetta's snap with bird comet
Probe prepares to make first landing on fast-moving rock
Archaeologists and robots on hunt for more Antikythera pieces
How much of the world's oldest computer can they find?
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.