Inner Speech

Michael JohnsonVAP HKU

Outline

1. Two Puzzles2. Separatism3. Why Inner Speech?4. The Computational Explanation5. Conclusion

1. TWO PUZZLES

Puzzle #1

Suppose we can think about propositions, probability distributions, and utility functions, and can compute expected utilities from them (or whatever). What does making any of these states conscious gain us?What is the purpose of conscious thought? If thinking is computational, how could something as obviously non-formal as consciousness make any difference?

Thinking in French

In About.com’s “French Language” article, author Laura K. Lawless speaks about the virtues of daily French practice: “Thinking about French every day will help you learn how to think in French, which is a key element of fluency.” Lawless assumes a quite natural view, namely that one can think in this or that natural human language.

Thinking in English

It seems to me, a monolingual English speaker, that whenever I’m conscious of thinking, I’m thinking in English. Sometimes I can’t find the words to express what I want to say, and there’s a ‘gap’ in the interior monologue. I suppose it’s filled with thinking—thinking of what to say—but I don’t experience that thinking. All the thinking I experience is English-thinking.

Thinking in Language

“[A]fter much practice, we no longer really need to call forth a symbol, we do not need to speak out loud in order to think. The fact remains that we think in words or, when not in words, then in mathematical or other symbols. Without symbols we would further hardly raise ourselves to the level of conceptual thought.” Frege,

Puzzle #2

Let’s call thinking in English or French or Cantonese ‘inner speech.’ What the last observation suggests is that inner speech is the phenomenal character of thought. This itself is puzzling because we know that the language of thought is not English (or French or Cantonese). Why is thought (≠ English) experienced as English?

Arguments that LOT ≠ English

Extensional inequivalence:

• Pre-linguistic infants think (else they can’t learn languages).

• Deaf adult humans who don’t know sign-language (or a spoken language) think.

• Non-human animals think.

Arguments that LOT ≠ English

Computational inadequacy:

• LOT articulates elements unarticulated by English (PRO, pro, etc.)

• LOT is scopally unambiguous where English is not– every thought of “Every boy loves some girl” is determinate as to the order of the quantifiers.

Puzzle #2 is Deeper

It wouldn’t really matter if LOT were English. It would still be weird for it to have a phenomenal character similar to perceived spoken English.

One way to see this is to suppose representationalism (e.g. Dretske 1997) is true. The p.c. of a conscious state = the property that state represents.

The Puzzle, Assuming Rep’ntationalism

Then since the p.c. of perceived spoken English is roughly the same as the p.c. of inner speech, they should represent roughly the same thing.

But my auditory perceptions of English represent sounds, and the vast majority of my thoughts (those not about sounds) don’t represent sounds.

Puzzle #2

I don’t want to assume that representationalism is true. But the assumption foregrounds a genuine oddity, no matter your theory of consciousness: thought and perception of spoken English (Cantonese/ whatever) are radically different. Why should they be phenomenally similar?

2. SEPARATISM

Puzzle #1 Redux

Many of our perceptual states are conscious, in that they have phenomenal characters. Suppose as a result of retinal stimulation, our visual perception module can segment scenes into edges, edges into boundaries, boundaries into objects, objects into parts, etc. What does making any of these states conscious gain us?

Consciousness as a Free-Rider

Nothing, and that’s the standard view. That these states are conscious is necessitated by their causal and representational properties (or whatever). We can’t make a state without the relevant causal/ representational properties conscious, and we can’t make a state with them non-conscious.

Consciousness as a Free-Rider

Maybe thoughts are like perceptions. They have phenomenal characters that supervene on their causal and representational properties. Consciousness adds nothing, because consciousness cannot be added to anything.

An example of such a view might be Dennett [cite]. In Dennett’s view, for a state to be conscious is just for it to occupy a certain sort of influential role with respect to memory and action. Something that doesn’t occupy that role can’t be “made conscious” unless that means “made to occupy that role.” [Dennett thinks that there isn’t any phenomenal consciousness though, just access consciousness.]

Problem

But only some very small number of thoughts are conscious. So we face a dilemma: either we reject the claim that the causal or representational properties of thoughts necessitate their having p.c.’s or we find some causal or representational difference between the conscious ones and the others. What could such a difference be? (Cf. Dennett)

Reason to Reject Thoughts with P.C.

The conscious properties of perceptions are not affected by our past experiences. I don’t learn how to see redness when I look at red things. But until I learn, say, French, none of my thoughts are accompanied by inner French. I can’t see “in French” but I can think “in French”.

Second Reason

Everyone with normal, functioning sensory faculties sees/ tastes/ feels/ etc. things in much the same way. But what it’s like for me and a cognitively normal monolingual French speaker to think that it’s mom’s birthday on Tuesday is different.

Puzzle #2 Redux

Even if we manage this dilemma, we’re still stuck with Puzzle #2. Why is the phenomenal character of thought so much like the auditory perception of English (Cantonese) utterances?

Separatism

Separatism holds that thoughts are never conscious. What happens in the case of inner speech is that a thought causes a perceptual state, and the perceptual state is conscious (as outlined in the solution to Puzzle #1). So thinking about my mother has no p.c. but it might cause states that do, like a mental image of my mother or an auditory “image” of the word ‘mom.’

Evidence for Separatism

The strongest evidence for separatism (with respect to thought vs. inner speech, at least) is the more-or-less complete overlap (modulo motor activation) between brain activation in speech production and brain activation in inner speech production.

Brain Areas Implicated in Speech

• Lexical selection: left middle of temporal gyrus• Syntactic encoding: Rolandic operculum, left

inferior frontal gyrus• Phonological code retrieval: right SMA, left

anterior insula, middle temporal gyrus (Wernicke’s area)

• Phonological encoding: the left posterior inferior frontal gyrus (Broca’s area) and the left mid superior temporal gyrus (STG)

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 the motor activation. (There’s equivocal evidence that some areas are differentially sensitive.)

Broca’s Area

Finally, patients with damage to Broca’s area can suffer expressive aphasia– an inability to speak or write words.Transcranial magnetic stimulation of Broca’s area has been shown to inhibit inner speech (interferes with a covert syllable-counting task).Some evidence suggests Broca’s area is more active in inner speech than overt speech.

Why Inner Speech?

But here’s where the current consensus ends, and problems remain unresolved. How does inner speech help? If you’re thinking in a logically perspicuous language (LOT), why go to the lengths of translating that into a less perspicuous language (English), which you then proceed to not think in? Why inner speech?

The Problem

Let’s be clear where we are. We had a puzzle as to why thoughts are conscious in the first place, and a puzzle as to why the phenomenal character of thoughts was English (or French or whatever). Separatism has a solution to both puzzles: it denies that thoughts are conscious and maintains that the phenomenal character of inner speech is expected, given that inner speech is more-or-less auditory imagery.

The Problem

But the analog of both puzzles reappears. Now it’s not “why is thought conscious?” but “why is unconscious thought accompanied by inner speech?” Furthermore, why is it inner speech, given that we know that English is less logically perspicuous than LOT?

3. WHY INNER SPEECH?

Three Explanations

Here are three potential explanations:1. There’s no benefit to inner speech, it’s a side-

effect of something else.2. There’s a benefit to inner speech, namely

that it’s conscious whereas thought is not and cannot be (the separatist consensus).

3. There’s a benefit to inner speech, but one that has nothing to do w/ its consciousness.

Side-Effect Explanation

Here’s the sort of story one might tell: for conversation, we need to translate LOT into English quickly. Maybe the mechanism that does that translates all the thoughts in the relevant buffer, without regard to whether you want to give voice to them. So when you’re sitting by yourself, that’s what you’re hearing– even though it does you no good at all.

Something Like This?

This particular explanation won’t work (why in the world would it route them through hearing? What you need for rapid conversation is quick translation from thought to speaking.)

But could something like it work?

Not a Side-Effect

I don’t think so. There’s a fair bit of literature on the benefits gained by inner speech. They include higher self-awareness, greater intelligence, improved mathematical ability, and better memory.

Inner speech is doing something. The question is how it is doing it.

Consciousness Explanation

A second possible explanation goes something like this: “Wow, if the separatist is right, then thoughts aren’t conscious. But consciousness has all these benefits right? Like, it’s a “global workspace” that makes information available, um, globally. So we translate our thoughts into inner speech to gain the consciousness benefits inner speech has by right of its perceptual nature.”

Wrong Order of Explanation

But this line of reasoning has the order of explanation backwards. It’s fine to say that the computational role (e.g. global accessibility) of something necessitates its having a phenomenal character. But things don’t go the other way: p.c.’s don’t necessitate things having certain computational roles. And even if they did, that wouldn’t explain why you couldn’t give thought the relevant c.r. and skip the inner speech.

Linguistic Encoding

There’s also the question as to how something linguistically encoded (like inner speech) could in principle be globally accessible. Just how many mental faculties can process language?

Computational Explanation

I’m going to argue for the third possibility. Inner speech does have a purpose (contra possibility #1), but that purpose doesn’t lie in the fact that it’s conscious (contra #2). Instead, inner speech has computational properties that make it of use; its consciousness is a side-effect of its status as a perception, not what’s worthwhile about it. The consciousness of inner speech is a red herring.

4. THE COMPUTATIONAL EXPLANATION

Adding Numbers

Suppose I ask you, out loud, to add “five million, four hundred and three thousand, nine hundred and ninety four and four hundred and forty six thousand, eight hundred and thirteen.”Probably, you can’t do it. Maybe you can, if you were quick enough to write down the numbers as I was saying them. And then when you solved the problem you’d use paper and pencil as well.

Why Not Native?

But why don’t you use your native number representations and your native addition algorithm to solve the problem? Why not take your concept of 5,403,994 (which was activated when you understood me saying “five million, four hundred and three thousand…”) and your concept of 446,813, and then add them together using LOT’s addition algorithm?

Possibilities

• Maybe LOT can’t add. You can think 5, and you can think 2, and you can think 5 + 2, but there’s no program in LOT that will take you from there to 7.

• Maybe LOT can’t add large numbers. Maybe its addition algorithm is a lookup table that doesn’t handle arguments higher than 8.

More Possibilities

• Maybe there is a native algorithm for addition, but it’s inefficient for large inputs.

• Maybe we can add natively, but we can’t convert the sums back into English.

• Maybe we are like chimps and gorillas and don’t even have the concept of 446,813. You can’t compute functions over representations you don’t have.

Benefits of Paper

Benefits of Paper

Even if you have no native concept of numbers, or no means of natively computing sums with such concepts, you can still write down Arabic numerals and compute sums with them (provided you can recognize shapes and you remember what shapes to write down when you see which other shapes, etc. You can be a Chinese… er… Arabic Number Room, even as an innumerate.

Visualization

And when we don’t have paper, we can resort to the next best thing: mental paper. We can imagine the symbols written out– re-create our perceptions of the written symbols– and manipulate them in imagination.

Arabic numerals provide an advantageous representational format for solving arithmetic problems.

The suggestion then is that linguistic expressions provide an advantageous representational format for solving epistemic problems (what should I believe, given my evidence?).

The way I’m imagining this happening is this. Suppose for whatever reason our native machinery can’t work out some instance of, say, disjunctive syllogism. Let’s say that it’s just incapable of inferring the right disjunct from a disjunction and the negation of its left disjunct.

We have the ability to translate these LOT premises (conditional and antecedent) into English. So suppose we do that and get:

“P or Q”“not-P”

Now the problem no longer requires us to execute disjunctive syllogism. If we’ve learned the rule “When you’ve got something of the form ‘P or Q’ and something of the form ‘not-P,’ you may conclude ‘Q’”, then a simple step of modus ponens gets us to “Q,” and translating back into Mentalese gets us our answer.

The Lesson

Learning rules to manipulate symbols in inner speech gets us around the need to have the ability to manipulate the analogues of those symbols in thought.

Let’s spell out the possible advantages again:1. Maybe our native algorithms can’t solve

certain decision problems or can’t solve decision problems with a certain degree of complexity.

Remember that some of the benefits of inner speech (according to psychologists) are higher intelligence and higher mathematical ability.

2. Maybe the native algorithms are, from the point of view of the problems we want to solve, crude heuristics which we can improve upon.

Consider the Wason selection task. To solve it, I have to think about it. Why is that? Because my native heuristic gives me the wrong answer

A final possibility is that inner speech may allow us to get by without certain concepts. Fodor argues that you can’t learn concepts like CARBURETOR. Most people think concepts like CARBURETOR are not innate. Put those views together, and it seems likely that we haven’t got CARBURETOR. But how are we so successful vis a vis carburetors?

Here perhaps we just skip thought altogether. We have a stored set of English sentences involving the word ‘carburetor.’ When we hear a new ‘carburetor’-sentence, or find ourselves in circumstances where we’re trained to say ‘carburetor,’ we take out the store of sentences (or some of them), try to derive consequences from them and the new sentence, and if any of the consequences translate back into Mentalese as “duck!” we behave appropriately.

Final Thought

We’re a lot smarter than everything else on the planet. Why is that? It’s common to think that language has something to do with smarts. This is appealing, because then we only have to posit one difference between us and the non-human animals: either language gives us smarts, or smarts gives us language; so having one gives us both.

Why We are So Clever

Fodor suggests: “[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.I think it's likely that we are the only creatures that can think about the contents of our thoughts.”

Suggestion

So Fodor’s claim is that we’re so smart because we can think about the contents of our thoughts. But why do we have this ability and apes not? Suggestion: we don’t. It’s not that we can think about the contents of our thoughts, but that we can represent the contents of our thoughts in inner speech, and reason with these representations in the way that Fodor suggests.

5. CONCLUSION

Two Puzzles

Puzzle #1: Why are thoughts conscious? What does consciousness add?

Puzzle #2: Why is the phenomenal character of thoughts English? Shouldn’t it… not be?

The Separatist Solution

According to separatism, the solution to the puzzles runs as follows. Thoughts aren’t conscious, they cause other states that are. So puzzle #1 does not arise. These other states are (roughly) auditory imagery. So the phenomenal character of these states is precisely as we’d expect. Hence puzzle #2 does not arise.

The Lingering Puzzles

But this only pushes the problem back.

New puzzle #1: Why have thoughts and these other things? What do they add?

New puzzle #2: And, of all things, what does their linguisticiness add? Isn’t LOT better than natural language (more perspicuous, e.g.)?

The Computationalist Solution

I’ve tried to suggest some ways in which linguistic representations could allow us to overcome computational limitations in the native machinery. They can conceivably augment the representational and computational power of our innate endowment. Perhaps, in allowing us to represent our own thoughts, they distinguish us from our less-smart cousins.

From Here

This is all very sketchy. My future plan of research is to investigate the empirical literature on the precise advantages of inner speech vs. lack thereof, and try to pinpoint what it’s actually doing (besides just outlining the possibilities).