0:02

Question of the Week

0:04

from the Naked Scientists

0:12

Hello and welcome to Question of

0:14

the Week. This week we're answering

0:16

this question sent in by listener

0:18

Walter, who asks, What language do

0:20

the profoundly deaf think in? Good

0:23

question Walter. Profound deafness

0:25

is when an individual can hear

0:27

nothing, save for occasionally extremely loud

0:29

sounds. So if you do

0:31

not hear sounds including those of people and

0:34

yourself talking, what form do your thoughts take?

0:37

Well that depends on when the individual became

0:39

profoundly deaf. As deafness cognition

0:41

expert at UCL, Bensie Wall

0:43

explains. Somebody who's

0:45

become deaf late in life

0:48

and who grew up only speaking English,

0:50

their dreams are going to be in

0:53

English. A person who

0:55

was born deaf, the languages they

0:57

might think in are

1:00

going to be related to

1:02

the languages they know. You

1:04

can see young deaf children

1:06

signing to themselves, just

1:08

the way young hearing children speak

1:11

to themselves. So if your

1:13

deafness came on in later life, it's highly

1:15

likely you will retain the language you heard

1:17

growing up as the one you think in.

1:19

But those born deaf will see or even

1:21

feel themselves signing in their head. The

1:24

most interesting research is on

1:26

deaf people with schizophrenia. People

1:29

who had some hearing in

1:31

their lives but became deaf

1:34

later, they're perfectly able to

1:36

imagine just a voice talking

1:38

to them. People who were

1:40

born deaf do report voices,

1:42

hearing voices, being in

1:45

conversation, but there's always

1:47

an image of

1:49

a face or a person to go with it

1:52

because that's their experience of

1:54

spoken language, that you only

1:56

communicate when you can see

1:59

a person. Fascinating stuff.

2:01

But with this being a language, same

2:03

as any other, does it develop in

2:05

the same way as spoken language among

2:07

those profoundly deaf at birth? Here to

2:09

explain that is Burbeck University of London's

2:12

Victoria Mowgli. We know from research

2:14

with hearing children that younger kids more so

2:16

than older kids are likely to use and

2:18

to benefit from overt self-talk

2:21

during certain tasks, so talking their way

2:23

through certain things. It seems like after

2:25

about five years of age, kids do

2:27

this less and it's also less useful

2:29

for them. So this could be

2:32

around the time where we start to see

2:34

the development of covert self-talk or inner voices

2:36

in young children. We also

2:38

know that profoundly deaf kids who

2:40

experience full native language access early

2:42

in life achieve very similar cognitive

2:44

and linguistic milestones to hearing children.

2:47

So I would expect that deaf and hearing

2:49

kids would develop inner voices at pretty similar

2:51

ages and that both deaf

2:53

and hearing kids inner voices likely reflect

2:56

their language and communicative experiences up until

2:58

that point, but we would need

3:00

more research to test these hypotheses. So

3:03

there you have it. Thank you to Walter

3:05

for the question and to Bensie Wall and

3:07

Victoria Mowgli for the answer. Next time we're

3:09

answering this question sent in by listener David

3:11

who asks, can an action

3:13

ever truly be replicated? Excellent

3:16

question and we shall hope to have an answer

3:18

for you next time. In the

3:20

meantime if you think you know the

3:22

answer or have a question of your

3:24

own, send it in as a voice

3:26

note to chris at the nakedscientists.com or

3:28

check us out at the forum nakedscientists.com/forum.

3:31

Question of the Week is part

3:33

of the Naked Scientists podcast and

3:36

supported by the Welcome Trust and

3:38

UK FAST. Look us up online

3:41

at nakedscientists.com