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

Examples  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

Blindsight and the Dorsal Stream  Lesions (usually due to stroke) in primary visual cortex cause a region of blindness called a scotoma  Identified using perimetry X

Blindsight and the Dorsal Stream  Patients with lesions to primary visual cortex occasionally retain some visual abilities:  better than chance performance on forced-choice 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 forced-choice 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 “WHAT” “WHERE”

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

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

Object Substitution Masking

 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 M TIME

XXXXX Masked Priming S P A M TIME

S P _ _ XXXXX Masked Priming S P A M 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

The Hard Problem Returns  MYSTERY: what is special about neural activity that leads to awareness ? NOBODY KNOWS !