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

LEFT MIDDLE TEMPORAL GYRUS, MID SECTION

SYNTACTIC ENCODING be cat mat NPST on 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 be NPST on the mat /mæt/ /ð ə / /kæt/ / ɪ z// ɒ n/ /ð ə /

RIGHT SUPPLEMENTARY MOTOR AREA

LEFT ANTERIOR INSULA

WERNICKE’S AREA

PHONETIC ENCODING /ð ə kæt ɪ z ɒ n ð ə mæt/

PHONETIC ENCODING /ð ə kæt ɪ z ɒ n ð ə 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 short- term 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 language- based 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!