Idea Journals Due on Thursday You may hand in: Printed pages if they are stapled or otherwise bound together Hand written pages so long as the writing

Idea Journals

• Due on Thursday

• You may hand in:• Printed pages if they are stapled or otherwise

bound together• Hand written pages so long as the writing is

legible

• Not possible to hand these in late!

Subconscious Cognition?!

What you don’t know, might help you…or it might not!

Perception and Cognition

• We have elaborate perceptual mechanisms to provide information to our brains to guide current or future behavior

Perception and Cognition

• We have elaborate perceptual mechanisms to provide information to our brains to guide current or future behavior

• Notice there’s no mention of consciousness

Blindsight and the Dorsal Stream

• The Dorsal Stream is thought to mediate much spatial processing and interaction with the environment

“WHAT”

“WHERE”

Object Substitution Masking

• Masking occurs when one stimulus impairs perception of a nearby stimulus

• In special cases the stimuli don’t have to overlap in space or time!?

• Object substitution masking occurs when attention cannot select a target object before it vanishes …AND…

• A mask is visible at the target location after the target has vanished



• Surprisingly, some visual information survives masking

• Subjects are accurate at reaching to grasp a masked shape even though they can’t consciously see it

Masked Priming

• Surprisingly even the meaning of visual information can survive some kinds of masking

Masked Priming

S P A MTIME

XXXXX

Masked Priming

S P A MTIME

S P _ _

XXXXX

Masked Priming

S P A MTIME

Masked Priming

• Subject must complete the stem to make any word other than the word that was masked

Masked Priming

• Subject must complete the stem to make any word other than the word that was masked

• Subjects are more likely to use masked word…indicates subconscious influence on behavior

The Hard Problem Returns

• MYSTERY: what is special about neural activity that leads to awareness ?

NOBODY KNOWS !

Vokey & ReadS T U D Y

l a n i m i l b u Ss e g a s s e M

Two Themes

• What were the two themes of this article?

Two Themes

• What were the two themes of this article?

1. Do so-called subliminal messages work?

2. Is it possible that not all “messages” were put there by evil rock stars (or Satan)?

Subliminal Messages

• What two kinds of subliminal messages do the authors investigate?

Subliminal Messages

• What two kinds of subliminal messages do the authors investigate?– “backmasking” - backwards messages in

songs

Subliminal Messages

• What two kinds of subliminal messages do the authors investigate?– “backmasking” - backwards messages in

songs

– words embedded in the background of images

Backmasking

• “Backmasking” is not backward masking (if you’re going to argue that some perceptual phenomenon is the work of Satan, at least get the name right)

Backmasking

• “Backmasking” is not backward masking (if you’re going to argue that some perceptual phenomenon is the work of Satan, at least get the name right)

• controversy in the 80’s - subliminal “backmasked” messages in rock music

Backmasking

• Examples of Gary Greenwald’s demonstrations (warning: you are about to hear a backmasked “message”)

Forward Backward

Does Backmasking Work?

• What can subjects tell about backwards messages?


• What can subjects tell about backwards messages?– Sex of the speaker– Language (barely)– Different speaker (barely)


• What don’t backwards messages convey?


• What don’t backwards messages convey?

–Meaning


• Some Examples of the experiments that Vokey & Read did:

• Subjects were presented with various phrases played backward. Subjects were unable to:– Accurately discriminate between questions

and declarations– Sort sentences into the category of

message (i.e. satanic, Christian, nursery rhymes, etc.)


• The meaning of backmasked messages is not consciously perceived (sufficiently to enable performance on these tasks).

• Might such messages still influence behavior?


• Priming by backmasked message?


• Priming by backmasked message?• Subjects presented with passages that use

the less common of two homophones tend to use that word when asked to spell it– e.g. climbing Mt. Everest is an incredible feat


• Priming by backmasked message?• Subjects presented with passages that use

the less common of two homophones tend to use that word when asked to spell it– e.g. climbing Mt. Everest is an incredible feat

• Subjects heard backwards sentences containing uncommon words

If backwards messages have subliminal influence, what would you predict?


• Priming by backmasked message?• Result: there was no biasing of the less

frequent homophone by exposure to it in a backward message


• Priming by backmasked message?• Result: there was no biasing of the less

frequent homophone by exposure to it in a backward message

• Interpretation: backmasked messages are not effective at influencing behavior


• Priming by backmasked message?• What are some counterarguments one

might make?



might make?– Perhaps repeated exposure is necessary



might make?– Perhaps repeated exposure is necessary– Null findings do not prove the absence of

an effect



might make?– Perhaps repeated exposure is necessary– Null findings do not prove the absence of

an effect• one needs to know the statistical power

Are All Subliminal Messages Intentionally Inserted?

• These messages tend not to be clear and obvious



• Could it be that our brains mistakenly see or hear messages that aren’t really there?




• Do brains make stuff up!?




• Do brains make stuff up!?

Absolutely! All the time.


• Is there really a dog or are the spots enough like a dog for your brain to fill in the rest?


• Some other examples brains making guesses with your perception

• Missing fundamental, color constancy, Kaniza triangle,the blindspot, illusory conjunctions, misinformation effect, false memories

Subliminal “Messages” Where you Least Expect Them

• How did Vokey and Read test the idea that subliminal messages might just be a case of mistaken perception?


• They examined passages from various sources (Jabberwokey and the 23rd Psalm) played backwards to identify candidate messages

The “subliminal” message is:


• They examined passages from various sources (Jabberwokey and the 23rd Psalm) played backwards to identify candidate messages

The “subliminal” message is: “saw a girl with a weasel in her mouth”


• Listeners were given each passage (backwards) and asked to listen for 12 possible messages

• Listeners detected “messages” in the appropriate passage


• Interpretation: Your brain is remarkably good at “active construction” of patterns amid a background of noise.


• Interpretation: Your brain is remarkably good at “active construction” of patterns amid a background of noise.

• Creative listening by (well-meaning?) public censors can go very wrong


• Consider the trial of Judas Priest– Band sued for inserting the message “do it”

which allegedly lead to the suicide of two teens

Listen for “Do It” The “do its”


• Consider the trial of Judas Priest– Band sued for inserting the message “do it”

which allegedly lead to the suicide of two teens

• Band acquitted on the basis of expert testimony

Expert Testimony !


• With enough creativity and patience one can see “subliminal messages” just about anywhere:


• Our perceptual mechanisms are great at extracting meaningful images from noisy stimuli. For example - the famous face on Mars:

Viking, 1976


• Given a clearer picture it looks a lot less like a face:

Mars Global Surveyor, 2001

Summary

Sensory Signals

Sensory Memory

Short-Term Memory

Long-Term Memory

ATTENTION

REHEARSAL

RETRIEVAL

Documents

Idea Journals Due on Thursday You may hand in: Printed pages if they are stapled or otherwise bound together Hand written pages so long as the writing