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

NEURAL CORRELATES Lexical selection: left middle temporal gyrus, mid section Syntactic encoding: Left inferior frontal gyrus (Broca’s area), middle frontal gyri, superior parietal lobule Phonological code retrieval [encoding]: right supplementary motor area, left anterior insula, Wernicke’s area Phonetic encoding: 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.

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?

SALIENT DIFFERENCE A salient difference between thought and audition is that the former is essentially non-perceptual and the latter is essentially perceptual.

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 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. 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!