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
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
• Lot’s of information gets processed and
used by your brain without you noticing
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
• Lot’s of information gets processed and
used by your brain without you noticing
• Consider some examples
Masked Priming
Masked Priming
S PAM
TIME
Masked Priming
XXXXX
S PAM
TIME
Masked Priming
SP__
XXXXX
S PAM
TIME
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
Blindsight and the Dorsal Stream
• Patients with lesions to primary visual
cortex occasionally retain some visual
abilities:
– better than chance performance on forcedchoice discrimination tasks
– spatial navigation and coordination (i.e. avoid
obstacles, interact with environment)
Blindsight and the Dorsal Stream
• Patients with lesions to primary visual
cortex occasionally retain some visual
abilities:
– better than chance performance on forcedchoice discrimination tasks
– spatial navigation and coordination (i.e. avoid
obstacles, interact with environment)
• Thought to be because of other “backdoor”
pathways that send signals to the Dorsal Stream,
A.K.A the “Where and How Pathway”
Blindsight and the Dorsal Stream
• The Dorsal Stream is thought to mediate much
spatial processing and interaction with the
environment
“WHERE”
“WHAT”
Blindsight and the Dorsal Stream
• The Dorsal Stream is thought to mediate much
spatial processing and interaction with the
environment
• But the neural activity in these structures does not
(is not alone sufficient to) enter into consciousness
The Hard Problem Returns
• MYSTERY: what is special about neural
activity that leads to awareness ?
NOBODY KNOWS !
lanimilbuS
segasseM
STUDY
Vokey & Read
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?
Does Backmasking Work?
• What can subjects tell about backwards
messages?
– Sex of the speaker
– Language (barely)
– Different speaker (barely)
Does Backmasking Work?
• What don’t backwards messages convey?
Does Backmasking Work?
• What don’t backwards messages convey?
–Meaning
Does Backmasking Work?
• 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.)
Does Backmasking Work?
• The meaning of backmasked messages is
not consciously perceived (sufficiently to
enable performance on these tasks).
• Might such messages still influence
behavior?
Does Backmasking Work?
• Priming by backmasked message?
Does Backmasking Work?
• 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
Does Backmasking Work?
• 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?
Does Backmasking Work?
• Priming by backmasked message?
• Result: there was no biasing of the less
frequent homophone by exposure to it in a
backward message
Does Backmasking Work?
• 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
Does Backmasking Work?
• Priming by backmasked message?
• What are some counterarguments one might
make?
Does Backmasking Work?
• Priming by backmasked message?
• What are some counterarguments one might
make?
– Perhaps repeated exposure is necessary
Does Backmasking Work?
• Priming by backmasked message?
• What are some counterarguments one might
make?
– Perhaps repeated exposure is necessary
– Null findings do not prove the absence of an
effect
Does Backmasking Work?
• Priming by backmasked message?
• What are some counterarguments one 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
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?
Are All Subliminal Messages
Intentionally Inserted?
• Is there really a
dog or are the
spots enough like
a dog for your
brain to fill in the
rest?
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?
Subliminal “Messages” Where
you Least Expect Them
• The examined passages from various
sources (Jabberwokey and the 23rd Psalm)
played backwards to identify candidate
messages
The “subliminal” message is:
Subliminal “Messages” Where
you Least Expect Them
• The 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”
Subliminal “Messages” Where
you Least Expect Them
• Listeners were given each passage
(backwards) and asked to listen for 12
possible messages
• Listener’s detected “messages” in the
appropriate passage
Subliminal “Messages” Where
you Least Expect Them
• Interpretation: Your brain is remarkably
good at “active construction” of patterns
amid a background of noise.
Subliminal “Messages” Where
you Least Expect Them
• 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
Subliminal “Messages” Where
you Least Expect Them
• 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”
Subliminal “Messages” Where
you Least Expect Them
• 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 !
Subliminal “Messages” Where
you Least Expect Them
• With enough
creativity and
patience one can
see “subliminal
messages” just
about anywhere:
Subliminal “Messages” Where
you Least Expect Them
• Our perceptual mechanisms are great at
extracting meaningful images from noisy
stimuli. For example - the famous face on
Mars:
Viking, 1976
Subliminal “Messages” Where
you Least Expect Them
• Given a clearer picture it looks a lot less
like a face:
Mars Global
Surveyor, 2001
Summary
RETRIEVAL
ATTENTION
Sensor
y
Signals
Sensory
Memory
Short-Term
Memory
Long-Term
Memory
REHEARSAL