February 9 & 11th

The seat of the soul and

the control of voluntary movement - in fact, of nervous functions in general, - are to be

sought in the heart. The brain is an organ of minor importance.

Aristotle (from De motu animalium, 4th century B.C.)

This is weird, but interesting!

• fi yuo cna raed tihs, yuo hvae a sgtrane mnid too

Cna yuo raed tihs? Olny 55 plepoe out of 100 can.

i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt ! if you can raed tihs forwrad it

NBC Ch 3: Plastic brains, hybrid minds

• “Your own body is a phantom, one that your brain has temporarily constructed purely for convenience.”

• V.S. Ramachandran & S. Blakeslee

Visual mind games

• http://www.pbs.org/wgbh/nova/mind/games.html#

• http://www.bbc.co.uk/radio4/reith2003/lecture1.shtml

• http://psy.ucsd.edu/chip/ramaillusions.html

The Negotiable Body

• Experiment 1: The Extended Nose– “Your certain knowledge … constructed over a

lifetime [can be] negated by just a few seconds of the right kind of sensory stimulation.”

• Experiment 2: A pain in the … desktop?• Experiment 3: Sensation in a dummy hand.

The Extended Nose

• Two chairs in a line, one behind the other

• Person #1 sit in chair #1, blindfolded

• Person #2, site in front

• Person #3 stand beside #1

• Take right hand of #1 & index finger to #2’s nose. Move hand in a rhythmic manner so that index finger repeatedly strokes or taps #2’s nose in a random sequence like Morse code.

• At the same time, use your left hand to stroke #1’s nose with the same rhythm & timing.

• The stroking & tapping of #1 & #2’s noses should be in perfect synchrony.

#1#1

#2#2

#3#3

#3#3 Instructions for #3

A pain in the desktopDummy Hand

• Body-image supported by biological brain is quite plastic & highly & rapidly responsive to coordinated signals from environment.

• Image of physical body is a mental construct – open to continual renewal & reconfiguration.

• Bodies do change during our lifetimes.

Ramachandran’s Mirror Box – work with patients missing a

hand• Fool brain into thinking

missing limb was there.– Relieve pain from being

“clenched”• Despite probable presence

of some present genetic components in our body-images, there is also – and simultaneously – large scope for continual revision.

• Our brains depend on perceived correlations and a sense of our bodily bounds & locations - Ramachandran principle.

Ramachandran & Blakeslee

• “For your entire life, you’ve been walking around assuming that your “self” is anchored to a single body that remains stable and permanent at least until death … Yet these [results] suggest the exact opposite – that your body image, despite all its appearance of durability, is an entirely transitory internal construct that can be profoundly altered with just a few simple tricks.”

• Our brains seem to support highly negotiable body-images– Can readily project feeling & sensation beyond the

biological shell– New body image created that includes nonbiological

components

Phantom Limbs (Ramachandran )

Experience & Plasticity Occur in Biological Brains

• At birth brain has great structure & ability to build its own rules thru experience.– Most dramatic development of human brain

occurs during first 2 years from birth.

• Plasticity permits developing nervous system to adapt to its surrounding environment.– Capacity of brain to modify organization of its

neuron networks according to particular experiences of body.

Facts About Neuroplasticity

• FACT 1: Neuroplasticity includes several different processes that take place throughout a lifetime.– Neuroplasticity does not consist of a single type of

morphological change, but rather includes several different processes that occur throughout individual’s lifetime.

– Many types of brain cells are involved in neuroplasticity, including neurons, glia, & vascular cells.

• FACT 2: Neuroplasticity has a clear age-dependent determinant.– Although plasticity occurs over individual’s lifetime,

different types of plasticity dominate during certain periods of one’s life & are less prevalent during other periods.

Facts continued• FACT 3: Neuroplasticity occurs in brain under 2 primary conditions:

– During normal brain development when immature brain first begins to process sensory information through adulthood (developmental plasticity & plasticity of learning & memory).

– As adaptive mechanism to compensate for lost function and/or to maximize remaining functions in event of brain injury.

• FACT 4: The environment plays a key role in influencing plasticity.

– In addition to genetic factors, brain is shaped by characteristics of a person's environment & by actions of that same person.

• Consequence of neuroplasticity is that brain activity associated with a given function can move to a different location as a consequence of normal experience or brain damage/recovery. (Wikipedia)

Neural Opportunism• E.g., look at your room - What

info does biological brain actually bother to extract & process?

• Less than we might guess.• Human visual systems supports

only small are of high-resolution processing – fraction of visual field that falls into central focus (fovea).

• When inspect scene, brains move fovea around scene (in sequence of visual saccades; rate of 3/sec)– Humans presented with identical

pictures, but told to solve different kinds of problems show very different patterns of visual saccade.

Neural Opportunism

• Each saccade may be used to slowly build up detailed internal representation of salient aspects of scene….

• http://www.members.tripod.com/andybauch/magic.html

• Rely on our tendency to overestimate what we actually see in a single glance & on manipulation of our attention so as to actively inhibit extraction of crucial info at certain critical moments.

• Dennett’s card trick – at what point can you identify color of card.– Color sensitivity is available only in small,

central part of visual field.– My conscious experience – things look colored

all way out.

Card Tricks

Change Blindness

• Phenomenon where a person viewing a visual scene apparently fails to detect large changes in scene.

• For change blindness to occur, change in scene typically has to coincide with some visual, disruption such as a saccade (eye movement) or a brief obscuration of observed scene or image.

• When looking at still images, change blindness can be achieved by changing a part of image in 13 seconds or longer

• See movies

Change blindness for central objects can occur in real world

• Simons & Levin, 1998. • One experimenter approached pedestrian (subject) to ask for

directions. • During conversation, 2 other people rudely interrupted them

by carrying a door between experimenter & pedestrian. • During time that subject's view was obstructed, 1st

experimenter was replaced by a different experimenter. • Only 50 % of observers noticed change even though 2

experimenters wore different clothing, were different heights & builds, had different haircuts, & had noticeably different voices.

• Unless observers attend to & encode specific features that change, they will not detect difference. Simply attending to an object does not guarantee a complete representation of its features.

Stroop Effect

• //faculty.washington.edu/chudler/java/ready.html

• Words themselves have a strong influence over your ability to say the color.

• Interference between different information (what words say & color of the words) your brain receives causes a problem.

• Two theories that may explain Stroop effect:• Speed of Processing Theory: interference occurs because

words are read faster than colors are named. • Selective Attention Theory: interference occurs because

naming colors requires more attention than reading words

Kind of knowledge that counts

• May not be detailed knowledge of what’s out there • May be broad idea of what’s out there which informs on-the-

spot processes of info retrieval & use.• Visual brain may have hit upon a very potent problem-solving

strategy – preferring meta-knowledge over baseline knowledge.

• Meta-knowledge – knowledge about how to acquire & exploit information.

• Baseline knowledge – basic knowledge about the world.• Effect is often same – having super-rich, stable inner model of

scene allows you to answer certain questions rapidly & fluently, but so could knowing how to rapidly retrieve same info as soon as question is posed.

• E.g., say we know time just because we’re wearing a watch!

Doug Lenat & Cyc http://www.cyc.com/

• Cyc is an artificial intelligence project that attempts to assemble a comprehensive ontology and database of everyday common sense knowledge, with the goal of enabling AI applications to perform human-like reasoning.

• //video.google.com/videoplay?docid=-7704388615049492068

Visual Brain is opportunistic

• Always ready to make do & to get most from what world already presents rather than building whole inner cognitive routines from neural cloth.

• “Letting world serve as its own best model” (Rodney Brooks, roboticist). – http://people.csail.mit.edu/brooks/– http://www.ai.mit.edu/projects/humanoid-

robotics-group/cog/video.html– A good robot should use sensing frugally to

select & monitor just a few critical aspects of situation; rely on persistent physical surroundings to act as kind of enduring, external data-store.

World Brains• It just doesn’t matter

whether the data are stored somewhere inside the biological organism or stored in the external world.

• What matters is how info is poised for retrieval & for immediate use as & when required.

• Retrieval is some time hard.• Biological brain may not be

aware of what info is stored outside

What happens when opportunistic infant brains encounter world of

language?• Pan troglodyte chimpanzees• Thompson, Oden & Boysen • Trained chimps to associate plastic

token (e.g., red triangle) with any pair of identical objects (e.g., 2 shoes) & differently shaped toke with any pair of different objects (e.g., cup & shoe).

• Token trained chimps could solve more complex abstract problem – categorize pairs-of-pairs of objects in terms of higher-order sameness or difference.

• Shoe/shoe – banana/shoe different because relations within each pair are different.

• Chimps not trained could not learn how to solve problem.• How does token-training help chimps who had plastic

tokens & token-use training?• Researchers suggest that chimps’ brains come to associate

sameness judgments with inner image or trace of external token itself.– Now when see 2 items that are same activate inner

image of red plastic triangle.– Reduce tricky higher order problems to lower-order ones

defined not over world but over inner images of plastic tokens.

– www.indiana.edu/~cogdev/labwork/clark.doc • To generate effect, just need to associate lower-order

concepts (sameness & difference) with stable, perceptible items.

• Labeling is a cognitive shortcut!

It’s more than labeling• Cultural tool of public

language gives us labels and whole, structure, recursive systems for encoding, objectification, & communication of thoughts & ideas.

• Human brain is subjected to potent & empowering does of self-administered transformational medicine

• E.g., Joseph – deaf 11 year old who was never taught sign language & had no structured linguistic experiences in his childhood.

• “Joseph saw, distinguished, categorized, used; he had not

problems with perceptual categorization or

generalization, but he could not, it seemed, to much

beyond this, hold abstract ideas in mind, reflect, play, plan … he seemed, like an animal or an infant, to be stuck in the present, to be

confined to literal and immediate perception.”

• Oliver Sacks in Seeing Voices (1989)

Scaffolded Thinking

• How to profit from biological brain’s pattern-associating strengths while minimizing their weaknesses?

• One strategy – combine biological pattern-associating systems with various environmental props, aids & scaffoldings.– Pictures, spoken words, written words & diagrams &

digital media tools to get the most from our brains.

• We critique, rearrange, streamline & link with help of properties of external media which allow sequence of simple, pattern-associative reactions to become organized & to grow

• Brain acts as mediating factor.

Human thought is constrained in mental imagery

• In some very specific ways in which it is NOT constrained during online perception.

• Our mental images seem to be more interpretatively fixed & less able to reveal novel forms & components.

• Much harder to discover for first time the 2nd interpretation of ambiguous figures (duck/rabbit) in recall & imagination than when confronted with real drawing.

• People who couldn’t recall 2nd interpretation could draw what had seen 1st from memory & by perceptually inspecting their own memory-based drawing, find the 2nd interpretation.

Mind Tools

• Transform complex problems into ones that biological brain is better equipped to solve.– E.g., Martian artists vs. humans with external

props & media• Good, potentially transparent cognitive tools

“permit [users] to do tasks that need to be done while doing the kinds of things people are good at: recognizing patterns, modeling simple dynamics of the world, and manipulating objects in the environment.”