Explicit knowledge, higher order thoughts, and hypnosis

Zoltan Dienes

University of Sussex

1. A hierarchy of ways in which knowledge can be explicit

2. Highest level of explicitness <-> conscious awareness

3. Explicitness and control

4. Three possible accounts of hypnosis

5. Relation to existing theories of hypnosis

What is implicit or explicit knowledge?

 

Dienes & Perner, 1999:

 

One can explicitly represent just parts of, or all of, what it is to know a fact.

Consider the knowledge:

I see that it is a fact that the word in front of me has the meaning butter

There is a hierarchy of making this knowledge explicit.

One might just explicitly represent:

 i) the property

"butter”

 ii) the predication of the property to an individual

"The word in front of me has the meaning butter“

iii) the proposition's factuality

"it is a fact that p“

 

Active representations that are not fact explicit are simply taken to be true.

Considering different possible models of the world, past and present states of the same object, explicit memory, counterfactual reasoning all require representing factuality explicitly.

iv) the mental attitude of knowing, seeing, etc

“I see that it is a fact that p“

 Step (iv) is fully explicit knowledge; in previous steps the knowledge is to some degree implicit.

Relation between explicit knowledge and conscious knowledge?

Higher order thought theory of Rosenthal:

a mental state is conscious if we are conscious of being in that mental state;

we are conscious of being in a mental state when we have a thought that we are in that mental state;

in sum, a mental state is a conscious mental state in virtue of the person having a higher order thought that they are in that mental state.

 

Fully explicit knowledge <-> conscious knowledge

A second order thought (e.g. “I see that the cat is black”) makes one aware of the first order thought (“the cat is black”) and hence makes the first order thought a conscious thought.

The second order thought itself is not a conscious thought until one becomes conscious of it – by a third order thought (e.g. “I know that I am seeing that the cat is black”).

It is the third order thought that makes one consciously aware that it is *me seeing*.

Declarative representations

Declare what is the case.

i.e. must represent the full proposition explicitly AND represent that it is a fact – fact explicit.

Imperative representations

“If Y, then do X”

“Do X”

X and Y cannot be taken to be true

i.e. must also be fact explicit

Norman & Shallice (1986):

Supervisory Attentional System (SAS) (attention demanding, conscious control)

contention scheduling: selects according to level of activation, which is determined by trigger conditions of the schema and lateral inhibition/excitation between schemata.

SAS can bias activation values and is needed for

1) planning or decision making

2) Troubleshooting

3) learning new actions

4) technically difficult actions

5) overcoming strong pre-existing response

Perner, 1998

Two types of control (SAS and contention scheduling) relate to the implicit-explicit distinction.

All the executive tasks

e.g. following verbal instructions to implement new actions, planning

involve declarative representation of schema content "If S1 do A1" OR “Do A1” as a goal (often: as something desired).

(Conditionals and imperatives must be fact explicit.)

Technically difficult actions (4) also presumably refers to strengthening difficult actions by declarative representations.

Trouble shooting (2) and overcoming response (5) require one forms a declarative representation of what is to inhibited as well as what is to be achieved.

       Executive function tasks require fact-explicit representations of goals.

(Contention scheduling can use fact-implicit representations of conditions, actions, and goals.)

Perner (2002)

Vehicle control:

Action schema comes to control behaviour because of its vehicle properties i.e. degree of activation.

(predication implicit knowledge)

 

Content control:

Fact-explicit representation ("if condition C then do action A" or "do A") determines which schema comes to control behaviour (the schema with the conditions and action described by this representation).

Contention scheduling requires only vehicle control

Executive tasks require content control.

 

Content control-based system (the higher system) sets off action schemata, that then run according to vehicle control; the higher system may or may not monitor the results of the action schemata.

 

The higher system (a) can trigger the lower system; (b) and monitor its successful performance

Either or both of the above can lead to the representation "I am intending this action".

Sense of agency and intention comes from the higher order thought “I am intending this action”;

The function of this HOT is to

(i) track initial content control and

(ii) track consistency of vehicle control with any previous content control that may have set the vehicle control up

Hierarchy of voluntary action:

- Non-intentional: vehicle control produces an action not set by the higher system.

-Intentional: higher system sets up the lower system; when appropriate conditions are met, the schema executes the appropriate action. 

- absent-minded intentional action: lower system runs unmonitored, producing actions appropriate to plan.

- fully content-controlled intentional action: Higher system triggers and continuously monitors execution of action schema, over-riding when necessary.

fully content-controlled intentional action-without HOT: unconscious performance of executive function tasks??

 

-fully voluntary action, i.e. performed with HOT ("I intend to perform this action")

(and typically with 3rd order thought, making you aware of your intention "I know I am intending to perform this action").

Hypnosis. Three possible mechanisms:

1 Content control without a HOT.

2 HOTs without first order states.

3 Different "I" representations.

Content control without a HOT?

a) Suggestion to forget the number "four": "1,2,3,5,6,.." - must be content control, but person claims ignorance of doing anything strange => no second order thought.

b) Spanos, Radtke, and Dubreuil (1982): highs suggested to forget certain words in any type of task given to them produced those words at a below baseline level in a word association test. Content control, because the existing associations that would be produced by vehicle control must be suppressed.

In general, virtually any arbitrary behaviour can be hypnotically suggested despite the fact that such behaviour might be novel to the person, and many hypnotic suggestions require the person ignore some salient aspect of the situation (e.g. amnesia or analgesia suggestion) => many hypnotic responses are under content control.

Highs are especially good at dissociating HOTS from fact explicit representations?

Bowers and Woody (1996): (after hypnosis) highs could NOT think of their favourite car for 2 minutes more effectively than lows

How is the normal ascent from fact-explicitness to attitude explicitness prevented?

 

According to HOT theory, HOTS are just thoughts and so their occurrence will be sensitive to the same influences as other thoughts (Rosenthal, 2001). That is, consistent with the socio-cognitive approach, a HOT about intention might not occur because of

Beliefs and expectations: the expectation that the act will occur involuntarily prevents HOTS of intending from occurring.

Highs are especially able to control HOTs with expectations?

If tell highs to expect a state of affairs they should be more likely to consciously perceive it than lows.

Naish (1983): In a signal detection task (detect 300ms tones amongst 360ms tones), when subjects were told the signal would be more likely, the change in bias was higher for highs than lows

(based on verbal report: perceptual experience changed not just response tendency).

(cf Karlin, 1977; Dolby & Sheehan, 1977)

Assume: Third order HOTs (TOTs “I know I am intending to do X”) are easier to suppress than second order HOTs (SOTs “I am intending to do X”).

Maybe very highly hypnotizable subjects can suppress SOTs – so can do “forget 4” task.

Mediums can only suppress TOTs. The second order thought is still there making them aware of content of content control (“do not say 4”), making them aware of 4. So couldn’t do forget 4 task – or analgesia, amnesia, etc. But could do other tasks e.g. arm levitation (would not be aware of intending the arm to rise, so would appear involuntary.)

=> Order of difficulty of hypnotic tasks (cognitive harder than motor) explained?

2 HOTs without first order states.

Rosenthal (2000, 2001) : One can have a second order thought that one is in a certain first order state, without actually being in that state. It will seem to one that one is e.g. experiencing pain even though in fact one is not!

 

=> mistaken HOTs could produce many of the experiences brought about by hypnotic suggestion?

 

Such mistaken second order thoughts should be most likely to occur if one strongly expects the first order state to occur.

If expectations operate directly on HOTs, hypnotic hallucinations would not facilitate implicit perceptual tasks.

If expectations operate via suppressing intentions to imagine (i.e. the first mechanism: content control without HOTs), hypnotic hallucinations would involve brain pathways involved in perception.

Kosslyn et al (2000): PET scan indicated highs having visual hallucination had active visual pathways.

=> In this case, content control without HOT is a better explanation than HOT without first order content.

Speculation: dissociation between HOTs and first order states is brought about by expectations.

Consistently:

Kirsch (1985, 1991): Hypnotic experiences are the outcome of expectations .

 

Or is there some other mechanism by which or state in which HOTs are suppressed?? Are there individual differences in the mechanism/extent to which expectations can determine HOTs independently of first order content?

 

Evidence:

1) General responsiveness of hypnotic subjects to demand characteristics

2) For suggestions given with no induction, correlation between expectation of response and response = 0.53 (Braffman & Kirsch, 1999)

3) Post-induction, expectation of number of suggestions that will be experienced correlates highly with number of hypnotic suggestions experienced, r = .64 (Council et al, 1986).

4) Subjects pass more suggestions after an induction rather than without an induction only to the extent that they expect to (Braffman & Kirsch, 1999).

3. Different "I" representations

Kihlstrom (1997): subject creates an additional "Hypnotic I". Because the hypnotic I's intentions (causes of hypnotic responding) are not linked to the normal "I" the person does not experience himself as intending the actions to occur.

 

Possible mechanism, but complex.

Cannot be the basis of most hypnotic responding - it predicts a hidden observer, and a fully fledged hidden observer only occurs for about 5% of the population.

Content control is presumably easier with relevant HOTs to support it, they can add to and support the controlling activation.

Therefore, to engage in content control without HOTs, one must be good at content control.

Prediction: Highs should be better than lows at content control. Is this true?

YES – on a range of different type of cognitive tasks

Relatedly, with brain imaging techniques Crawford has argued highs respond to hypnotic suggestions with increase in blood flow in anterior frontal cortex (location of SAS).

1) Graham & Evans (1977): Highs better than lows at random number generation (failure to replicate: Crawford et al 1993)

2) Naish (1983): Highs can bias perceptual schemata more strongly than lows.

3) Dienes (1987): When hearing simultaneous lists of words, highs can select on the basis of representational content (semantic category) to a greater degree than lows, but they cannot filter according to purely sensory features any better than lows.

(cf Karlin, 1977; Dolby & Sheehan, 1977)

4) Dixon & Laurence (1992): Highs have greater strategic control over reversing the Stroop effect than lows.

5) Some evidence highs can maintain attentional focus better than lows (Das, 1964; Gur, 1974; Smyth & Lowry, 1983; Wallace & Patterson, 1984).

6) Some evidence that highs can co-ordinate the processing of multiple simultaneous information sources better than lows (Sigman, Phillips, & Clifford, 1985).

7) Some evidence that highs have faster reaction times to complex decision-making tasks than lows (Crawford, Horton, & Lamas, 1998).

Comparison with existing theories of hypnosis:

- Like socio-cognitive perspective (e.g. Spanos), our view emphasizes strategic nature of hypnotic responding

BUT we regard the lack of voluntariness as real;

- like neo-dissociation theory (Hilgard), the "executive ego" (SAS) is involved in responding

BUT there is not two streams of consciousness

- Bowers and Woody(1994): hypnosis involves a weakening of frontal lobe function and thus contention scheduling controls behaviour (hence the feeling of involuntariness):

 frontal lobe function must be less efficient without the HOTs to support it

BUT hypnotic responding cannot be based simply upon contention scheduling. Bowers and Woody’s theory fails to get to grips with the highly strategic and, when necessary, content-controlled nature of hypnotic responding.

like Bowers and Woody, control is split off from consciousness, BUT the SAS is still involved.

Kirsch & Lynn (1997): hypnotic responding is based on contention scheduling, and the generalized intention to perform action x whenever it is suggested; this "implementation intention" produces an automatic response (action x) whenever its satisfaction conditions (i.e. the suggestion) are obtained.

 

However, one cannot automatically perform tasks requiring content control, not even with generalized implementation intentions: One must specifically form the right fact-explicit representation and this goes beyond contention scheduling.

Conclusions

1. Executive function (content control) requires less explicit representation than conscious awareness (fact explicit vs attitude explicit)

2. Hypnotic responding often requires content control, but subjects do not have relevant higher order thoughts (attitude explicit representations) to make the content control conscious

3. The theories of Hilgard and Spanos - that hypnotic subjects respond strategically and with executive function – seem right. The analysis in (1) shows there is no need to try to force hypnotic responses into being based on contention scheduling to account for the lack of conscious intentions.