Supra- and subliminal priming Piotr Jaśkowski Department of Cognitive Psychology University of Finance and Management, Warszawa

Supra- and subliminal priming

Piotr JaśkowskiDepartment of Cognitive PsychologyUniversity of Finance and Management, Warszawa

incongr

RT

Task: Respond with the hand the arrow points to

congr

Source: Jaśkowski, Consc.Cogn., 2006

Prime is fully visible

What is supraliminal priming?

prime

target

What is subliminal priming?

Semantic priming

Source: Dehaene et al., Nature 1998



prime target

V-V six three

A-V 6 three

V-A six 3

V-V 6 3

Semantic priming



Priming effect

PE = RT(incomp.) – RT(comp.)

Positive compatibility effect (PCE):

Negative compatibility effect (NCE):

PE > 0

PE < 0



Semantic priming

PCE for all conditions

50 ms

comp. incomp.

RT

target

Respond to the target’s side

Source: Neumann & Klotz, Att Perform.1994

Motor priming


What is this talk about?

• Is it possible to control subliminal processing?

• How neutral is a neutral mask?• Is a double dissociation a proof for

subliminal processing?

Questions to answer

Is it possible to control subliminal processing?

Source: Merikle & Joordans, Consc.Cogn., 1997

Stroop-like task

######$&%$

267 ms

#####

33 ms

redSubliminal situation

300 ms

redSupraliminal situation

Task: call the target’s color



Stroop-like task

#####red

compatible condition: 25% trials

#####red

incompatible condition: 75% trials comp.

RT

incomp.

comp.

RT

incomp.

supraliminal

subliminal


• The reversed effect was found under the supraliminal condition, because under this condition participants had the possibility to ‘‘capitalize on the predictive information provided by the primes’’.

• Strategical control can be exercised only under supraliminal condition.

Stroop-like task


• If there is no control over subliminal stimuli:– It should be possible to trigger one’s response

against one’s will. – It should be possible to trigger one’s response by

means of several subsequently presented subliminal primes.


Problem


Source: Jaśkowski et al., J.Cogn.Neurosci., 2003

Multiple priming

Task: respond with left/right key depending on target position.

Target


35 ms35 ms

35 ms35 ms

35 ms35 ms

35 ms35 ms

prime duration = 11.6 ms

target duration = 100 ms




Condition 80/20- 20% compatible

prim

ing se

quen

ce

- 80% incompatible

Condition 20/80- 80% compatible- 20% incompatible

250

300

350

400

450

20-80 80-20

Rea

ctio

n tim

e (m

s)

comp

incomp


0.70

0.75

0.80

0.85

0.90

0.95

1.00

20-80 80-20

Pe

rce

nt

corr

ect

comp

incomp

Rea

ctio

n tim

e (m

s)



Conclusions:

• Even when stimuli are subliminal participants can control their influence on their behavior:– Plausibly, they can augment or damp the

subliminal influence off-line. – A need for such a regulation partcipants can

infer from observation of their own performance.



Source: Wolbers et al. Cerebral Cortex, 2005

Correction of performance is mediated by frontal cortex

Strategical control can be exercised only under supraliminal condition.


Source: P. Collins, www.philcollins.co.uk

• A mask reduces the participants’ conscious accessibility to the prime information, but it does not affect response to the target provided that the mask is neutral.

• A mask is neutral if it induces no response to the target.

How neutral is a neutral mask?

Negative compatibility effect

incongr

RT

Task: Respond with the hand the arrow points to

congr

Source: Eimer & Schlaghecken, JEP:HPP, 1998




Source: Verleger et al., JEP:General, 2004

negative

comp.

RT

incomp.

comp.

RT

incomp.

positive



A mask does not affect response to the target provided that it is neutral.


comp.

RT

incomp.

negative (NCE)

comp.

RT

incomp.

positive (PCE)

NCE vs. PCE

Source: eg. Klapp & Hinkley, JEP:Gen, 2002

Is a double dissociation an evidence for subliminal processing?

• NCE for masked and PCE for unmasked stimuli is a stronger evidence than for nonconscious influences. This dissociation shows that there are different mechanisms underlying conscious and nonconscious processing.

• If there is a qualitative difference in performance under the masking and nonmasking condition, it is a strong evidence for subliminal processing.

Source: Klapp & Hinkley., JEP:HPP, 2005


possible mask temporal positions


NCE: efficient maskingNCE: efficient masking

NCE: no maskingNCE: no masking


Source: Jaśkowski, JEP:HPP, in press

Source: Jaśkowski, JEP:HPP, in press

Negative compatibility effectNo masking at allNo masking at all


If there is a qualitative difference in performance under the masking and nonmasking condition, it is a strong evidence for subliminal processing.

before you conculude like this.

Oh, think twice...



Advice 3

• Have different types of priming (semantic, perceptual, motor etc.) common features (dynamics, persistence etc.)?

Arrowness

How far can you go with generalization?



mask

Source: Jaśkowski & Ślósarek, Consc.Cogn., in press

before you try to generalize your finding


Advice 4

Oh, think twice...


Conclusions

• We control if our performance is or not consistent with our goals even if the stimuli are subconsciously processed.

• A mask is not a neutral stimulus. It is actively processed and our behavior is corrected according to the information the mask brings.

• Not every double dissociation is an evidence for subliminality.

• Be careful with generalizations!

Documents

Supra- and subliminal priming Piotr Jaśkowski Department of Cognitive Psychology University of Finance and Management, Warszawa