WHY INNER SPEECH?
MICHAEL JOHNSON
HONG KONG UNIVERSITY
1. WHAT IS INNER SPEECH?
INNER SPEECH
As I’ll use the term, “inner speech” is a label for the phenomenon we naturally
describe as “thinking in English/ Cantonese/ Catalan/ Kalaallisut/ etc.”
But what is the nature of this phenomenon and how is it related to thought and
“outer” speech?
THOUGHT ≠ INNER SPEECH
Pre-linguistic infants have to be able
to think to learn– for example, to
learn a language.
They obviously think in something other
than a language they haven’t learned.
THOUGHT ≠ INNER SPEECH
Deaf adults who haven’t learned a
spoken or a signed language also
obviously think, but not in language.
THOUGHT ≠ INNER SPEECH
Finally, non-human animals think, but
none of them possess anything like a
human spoken or signed language.
THOUGHT ≠ INNER SPEECH
Greater indeterminacy of English compared with thought:
• Lexical ambiguity: “Fred went to the bank.”
• Structural ambiguity: “Flying planes can be dangerous.”
• Scopal ambiguity: “Every boy loves some girl.”
PROCESSES IMPLICATED IN SPEECH
•
Lexical selection: selecting lexical items
•
Syntactic encoding: arranging the lexemes according to the syntactic rules
•
Phonological code retrieval [encoding]: retrieving [producing] phonological
information
•
Phonetic encoding: Putting the information into an articulatory code
•
Articulation
LEXICAL SELECTION
be
cat
mat
NPST
on
the
the
LEFT MIDDLE TEMPORAL GYRUS, MID SECTION
SYNTACTIC ENCODING
be
cat
mat
NPST
on
the
the
SYNTACTIC ENCODING
the
cat
be
NPST
on
the
mat
LEFT INFERIOR FRONTAL GYRUS/ BROCA’S AREA
MIDDLE FRONTAL GYRI
SUPERIOR PARIETAL LOBULE
PHONOLOGICAL ENCODING
the
cat
/ðə/ /kæt/
be
NPST
/ɪz/
on
/ɒn/
the
mat
/ðə/ /mæt/
RIGHT SUPPLEMENTARY MOTOR AREA
LEFT ANTERIOR INSULA
WERNICKE’S AREA
PHONETIC ENCODING
/ðə kæt ɪz ɒn ðə mæt/
PHONETIC ENCODING
/ðə kæt ɪz ɒn ðə mæt/
BROCA’S AREA
LEFT MID-SUPERIOR TEMPORAL GYRUS
THE BRAIN AND INNER SPEECH
Importantly, in both inner speech and auditory visual imagery (imagining
someone else saying something), all these brain areas are active.
Many researchers (e.g. Bookheimer 2002) think the brain activity in inner
speech is the same as in overt speech– just a little less strong, and minus
phonetic encoding and articulation.
REDDIT THREAD: HOW DOES ONE “THINK” IN
FRENCH?
“Hi! As others have said, it comes with time and practice.
One thing I do that helps greatly is talk to myself in a foreign language (I don't
give a shit about looking insane to others, so I often speak to myself mezza voce
in the street). It helps getting confident with small sentences, how to introduce
yourself, how to talk about your day or something you're (un)happy with.”
THE PHENOMENAL CHARACTER OF I.S.
Inner speech is an auditory phenomenon.
The phrase “hear myself think” gets 1.4m google hits compared with 640,000
for “feel myself think.”
SUMMARY
• Inner speech is distinct from thought.
• Inner speech involves all of the brain areas used in encoding thought into
language except the areas involved in phonetic encoding and articulation.
• Inner speech is an auditory phenomenon
GENERAL MODEL
Thought
↓
Linguistic encoding (LE) of thought
↓
LE sent to speech production apparatus = outer speech
GENERAL MODEL
Thought
↓
Linguistic encoding (LE) of thought
↓
LE sent to auditory mechanism = inner speech
2. WHY INNER SPEECH?
“What good could talking to yourself do,
if you already knew what you intended
to say?” Dennett (1991 p. 301)
THE BASIC PUZZLE
Suppose I have a thought. If I don’t plan on communicating it to anyone in the
foreseeable future, why would I:
• Find the words that express the components of the thought;
• Arrange them according to the rules of grammar;
• Figure out how they would sound;
• And then “listen” to them?
POSSIBLE SOLUTION #1
There’s no reason why we engage in
inner speech. Only a befuddled
hyper-adaptationist would think there
had to be a reason.
NO FUNCTION?
The burden of proof is always on the side that wants to claim that a cognitive
feature is adaptive and does have a function.
That being said, there’s plenty of evidence that deficits in inner speech (either
temporary or permanent) result in severe cognitive impairment.
BENEFITS OF INNER SPEECH
Here are just some of the areas impaired by a deficit in inner speech:
•
self-awareness
•
intelligence
•
mathematical ability
•
memory
POSSIBLE SOLUTION #2
The reason has nothing to do with inner speech: inner speech is a side-effect.
SIDE-EFFECT STORY
For fully verbalized outer speech, it is necessary to encode our thoughts in
language, and to do so very rapidly.
Ideally, we would perform this encoding only when necessary, but nature is
rarely ideal.
Instead we perform the encoding even in those large number of instances where
we have no plans to engage in verbal behavior.
PROBLEMS FOR SIDE-EFFECT STORY
1.
The story doesn’t explain how inner speech conveys the benefits to
intelligence, memory, etc.
2.
There’s an extra step in inner speech that’s not needed in “outer” speech:
routing the phonological representations to the auditory cortex.
POSSIBLE SOLUTION #3
Inner speech is conscious whereas our
“unspoken” thoughts aren’t: inner
speech allows us to “globally
broadcast” information.
“GLOBAL BROADCAST” STORY
Carruthers suggests that inner speech exists as a medium for the different
modules to “talk to” one another.
This seems implausible. How could something linguistically encoded in principle
be globally accessible? Just how many mental faculties can process language?
HERE’S THE STORY I LIKE
A salient difference between thought and audition is that the former is
essentially non-perceptual and the latter is essentially perceptual. As we’ll see,
that makes quite a difference.
INNER SPEECH AND ATTENTION
BENEFITS OF INNER SPEECH
In the rest of the talk, I want to try to outline how it is that inner speech is involved in
what research says it’s involved in:
• Memory
• Mathematical Ability
• Self-Awareness
• Intelligence
ATTENTION
Attention involves selecting an aspect
of our perceptions (or our sensations)
and allocating additional cognitive
resources to that aspect.
ATTENTION
Attention can thus only be provided to
and withheld from perceptions and
sensations.
SHORT-TERM MEMORY
Knudsen (2007) sees attention as the means by which information enters shortterm memory.
Thus for information to enter short-term memory, it must come to us through
sensation or perception.
INNER SPEECH AND MEMORY
Inner speech, as I’ve argued, is an auditory phenomenon. Thus it, unlike ordinary
thought, is precisely the sort of thing we can attend to.
Unsurprisingly, research has shown that inner speech aids in memory (Baddely
1986).
BENEFITS OF INNER SPEECH
Memory
• Mathematical Ability
• Self-Awareness
• Intelligence
MEMORY AND MATHEMATICS
Performing all but the simplest
arithmetical calculations requires
storing the values of intermediate
calculations in short term memory.
MEMORY AND MATHEMATICS
If attention is essentially perceptual,
and is also the gateway to short-term
memory, then a perceptual
presentation of arithmetical problems
is necessary for solving them.
INNER SPEECH AND ARITHMETIC
This presentation can be visual (on a chalkboard, for example), but it can also
be auditory.
Research reveals that private speech increases arithmetical ability in children
(Ostad & Sorensen 2007) and that one of the cognitive deficits that faces deaf
individuals who have learned no language is poor arithmetical ability.
Memory
Mathematical Ability
• Self-Awareness
• Intelligence
SELF-AWARENESS
Self-awareness is “the capacity to become the object of one’s own attention
(Duval and Wicklund, 1972), where the individual actively identifies, processes,
and stores information about the self… Self-awareness involves attention paid
to one’s own mental states (such as perceptions, sensations, attitudes, intentions,
emotions, etc.) and public self-characteristics.” [Morin 2005, emphasis mine]
SELF-AWARENESS AND INNER SPEECH
“[T]hrough a process of labeling, categorizing, and engaging in languagebased modes of representation, a person not only represents internal states and
experiences (sentience) but acquires the capacity to reflect on them. [Burns &
Engdahl 1998: 179]
“Without language [internal monitoring remains] relatively primitive, vague,
unelaborated.” [171]
SELF-AWARENESS AND INNER SPEECH
Here’s the basic picture:
Awareness of our own thoughts is difficult to come by.
The best way to get it is to translate the thought into language, then “speak” it
to ourselves.
This allows us to attend to the thought and discover what we are thinking.
BENEFITS OF INNER SPEECH
Memory
Mathematical Ability
Self-Awareness
• Intelligence
WHY WE ARE SO CLEVER
“[A] creature that knows what would
make its thoughts true and what would
cause it to have them, would be in a
highly advantageous epistemic
position:…”
WHY WE ARE SO CLEVER
“It would be able, with premeditation, to cause itself to have true thoughts. In
particular, to construct, with malice aforethought, situations in which it will be
caused to have the thought that P if and only if the thought that P is true.”
WHY WE ARE SO CLEVER
“I think it's likely that we are the only
creatures that can think about the
contents of our thoughts.”
BENEFITS OF INNER SPEECH
Memory
Mathematical Ability
Self-Awareness
Intelligence
CONCLUSION
SUMMARY OF THE TALK
Part 1: Inner speech is speech that is not articulated. It is not thought itself, but
thought encoded linguistically.
Part 2: A puzzle arises as to how encoding our thoughts in a linguistic medium
conveys any benefit to us.
SUMMARY OF THE TALK
Part 3: The puzzle is resolved when we notice that attention is fundamentally
sensory/ perceptual.
We can attend to LEs in a way that we can’t attend to thoughts. This allows us to
store intermediate calculations so encoded in short term memory, and also
allows us to become self-aware of our thoughts.
This self-awareness is the fountainhead of human intelligence.
THANK YOU!