Zombie Fud

The plant genies

The plant genies donÕt manufacture imagination, nor do they market wonder and beautyÑbut they force us out of context so dramatically and so meditatively that we gawk in amazement at the ubiquitous everyday
wonders that we are culturally disposed to overlook, and they teach us
invaluable lessons about fluidity, relativity, flexibility and paradox. Such
an increase in awareness, if skillfully applied, can lift a disciplined,
adventurous artist permanently out of reach of the faded jaws of mediocrity.
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Robbins Rants

Tom Robbins is the author of numerous books, including Fierce Invalids Home from Hot Climates, Still Life with Woodpecker, Skinny Legs and All, Even Cowgirls Get the Blues and Another Roadside Attraction.
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6.6.1.3 Part 3

You should find that your friend’s spoken estimate of the second line is less than her estimate of the first, even though both lines were the same length. That’s the visual illusion. (If you used different length lines, this difference will be in relative terms.) And yet her walked-out estimates should be pretty much the same (i.e., not tricked by the illusion), or at least you should find she underestimates the second line’s length far less when walking. That is, her conscious judgment should be tricked more by this illusion (a version of a famous illusion called the Muller-Lyer illusion), than her walked-out estimate, controlled by her dorsal stream.

6.6.2. How It Works
How it works depends upon whom you ask. Advocates of the dual-stream theory of visual processing argue that these demonstrations, of the immunity of our actions to visual illusions, are evidence for the separateness of the dorsal (action) and ventral (perception) streams. The ventral stream is susceptible, they argue, because it processes objects relative to their surroundings, assessing the current context in order that we might recognize things. The dorsal stream, by contrast, is invulnerable to such illusions because it processes objects of interest in egocentric coordinates, relative to the observer, so that we might accurately interact with them.

Doubters of the dual-stream theory take a different view. One reason we are sometimes duped by illusions, and sometimes not, they argue, is all to do with the type of task, far less to do with there being separate processing pathways in our brain. For instance, when we view the Ebbinghaus illusion (Figure 6-6), we are typically asked to compare the two central disks. Yet, when we reach for one of the disks, we are focused on only one disk at a time. Perceptual tasks tend to involve taking context and nearby objects into account, whereas motor tasks tend to involve focusing on one object at a time and, by necessity, using egocentric coordinates to interact accurately. When changing the task conditions reverses these tendencies, the visuomotor system can be found to be susceptible to illusion or the perceptual system invulnerable.

Which argument is right? Well, there’s evidence both ways and the debate will probably roll on for some time yet.2,3 What is clear, is that this phenomenon provides yet another example [Hack #62] of how our illusory sense of a unified self keeps all these conflicting processes conveniently out of mind.

Does the world really appear as you’re seeing it? Who cares? Just sit back and enjoy the view, accurate or not, while your neurons fight things out.

6.6.3. End Notes
Aglioti, S. et al. (1995). Size contrast illusions deceive the eye but not the hand. Current Biology, 5, 679-685.

Franz, V. H. (2001). Action does not resist visual illusions. Trends in Cognitive Sciences, 5, 457-459.

Milner, D., & Dyde, R. (2003). Why do some perceptual illusions affect visually guided action, when others don’t? Trends in Cognitive Sciences, 7, 10-11.

Christian Jarrett

Taken from : Mind Hacks

6.6.1. In Action

In the mid-’90s, Salvatore Aglioti1 and colleagues showed that when people are presented with the Ebbinghaus illusion (see Figure 6-6) they find the disk surrounded by smaller circles seems larger than an identically sized disk surrounded by larger circles, and yet, when they reach for the central disks, they use the same, appropriate, finger-thumb grip shape for both disks. The brain’s conscious perceptual system (the ventral pathway) appears to have been tricked by the visual illusion, whereas the brain’s visuomotor (hand-eye) system (the dorsal pathway) appears immune.

There are many examples of situations in which our perception seems to be tricked while our brain’s visuomotor system remains immune. Here’s one you can try. You’ll need a friend and a tape measure. Find a sandy beach so you can draw in the sand or a tarmac area where you can draw on the ground with chalk. Tell your friend to look away while you prepare things.

6.6.1.1 Part 1
Draw a line in the sand, between 2 and 3 meters long. Now draw a disk at the end, about 70 cm in diameter, as in Figure 6-7A. Ask your friend to stand so her toes are at the start of the line, with the disk at far end, and get her to estimate how long the line is, using whichever units she’s happy with. Then blindfold her, turn her 90°, and get her to pace out how long she thinks the line is. Measure her “walked” estimate with your tape measure.

6.6.1.2 Part 2
Tell your friend to look away again, get rid of the first line, and draw another one of identical length. (You could use another length if you think your friend might suspect what’s going onit just makes comparing estimates easier if you use the same length twice.) This time, draw the disk at the end so that it overlays the line, as in Figure 6-7B. Now do exactly as before: get your friend to stand with her toes at the line start and guess the length verbally from where she is, blindfold her, and ask her to walk the same length as she thinks the line is.

Taken from : Mind Hacks

Sri Ramana Maharshi

Sri Ramana Maharshi, according to Ken Wilber,3 Òis arguably the greatest Guru who ever lived.Ó He has stated that the only reason we are not enlightened is that we do not know that we are already enlightened. While this is no doubt true, I have in my own some forty years of psychedelic exploration, enhanced by Tibetan Buddhist meditation practice, uncovered a vast variety of conditions that seemed to form barriers to this realization. Some of these are listed in the second paragraph above.
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6.5.2.2 How it works

This predictive process may also be at the root of why physical fights tend to escalate. Notice how tit-for-tat tussles between children (or indeed brawls between adults) intensify, with each person claiming that the other hit him harder. In a recent study,3 a motor was used to apply a brief force to the tip of each participant’s left index finger. Participants were then asked to match the force they felt using their right index finger to push down on their left index finger through a force transducer.

Results showed that participants consistently applied a stronger force than that which was applied to them. The authors suggest that, just as when we try to tickle ourselves, the brain predicts the sensory consequences of the self-generated force and then reduces the sensation. We can only predict the outcome of our own actions and not of someone else’s, so an externally generated force feels more intense. As a result, if you were to deliver a vengeful punch to match the force of your opponent’s blow, it is likely that you would overestimate the strength of the opponent’s punch and strike back harder.

Why have we evolved the inability to tickle ourselves? The force generation experiment shows that sensations that are externally caused are enhanced. Similarly, our reactions to tickling may have evolved to heighten our sensitivity to external stimuli that pose a threat. Our sensory systems are constantly bombarded with sensory stimulation from the environment. It is therefore important to filter out sensory stimulation that is uninterestingsuch as the results of our own movementsin order to pick out, and attend to, sensory information that carries more evolutionary importance, such as someone touching us. When a bee lands on your shoulder or a spider climbs up your leg, the brain ensures that you attend to these potentially dangerous external stimuli by ignoring feelings from your own movements. The predictive system therefore protects us and tickling may just be an accidental consequence.

6.5.3. End Notes
Blakemore, S-J, Wolpert, D. M., & Frith, C. D. (1998). Central cancellation of self-produced tickle sensation. Nature Neuroscience, 1(7), 635-640.

Blakemore, S-J, Frith, C. D., & Wolpert, D. W. (1999). Spatiotemporal prediction modulates the perception of self-produced stimuli. Journal of Cognitive Neuroscience, 11(5), 551-559.

Shergill, S., Bays, P. M., Frith, C. D., & Wolpert, D. M. (2003). Two eyes for an eye: The neuroscience of force escalation. Science, 301(5630), 187.

6.5.4. See Also
Weiskrantz, L., Elliot, J., & Darlington, C. (1971). Preliminary observations of tickling oneself. Nature, 230(5296), 598-599.

Wolpert, D. M., Miall, C. M., & Kawato, M. (1998). Internal models in the cerebellum. Trends in Cognitive Sciences, 2(9), 338-347.

Suparna Choudhury and Sarah-Jayne Blakemore

Taken from : Mind Hacks

Learning How to Learn

HE MOST IMPORTANT aspect of learning how to learn is to immerse oneself completely and without reservation into the Knower.
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Hack 65. Why Can’t You Tickle Yourself? (3)

One study used two robots to trick the brain into reacting to a self-tickle as if it were an external tickle.2 In the left hand, participants held an object attached to the first robot. This was connected to a second robot, attached to which was a piece of foam that delivered a touch stimulus to the palm of the right hand. Movement of the participant’s left hand therefore caused movement of the foam, as if by remote control. The robotic interface was used to introduce time delays between the movement of the participant’s left hand and the touch sensation on the right palm, and participants were asked to rate the “tickliness” (Figure 6-5).

When there was no time delay, the condition was equivalent to a self-produced tickle because the participant determined the instant delivery of the touch stimulus by movements of the left hand. Greater delay between the causal action and the sensory effect (up to 300 ms) meant participants experienced the touch as more tickly.This suggests that, when there is no time delay, the brain can accurately predict the touch stimulus so that the sensory effect is attenuated. Introducing a time delay increases the likelihood of a discrepancy between the predicted and actual sensory effect. As a result, there is less attenuation of the tickly sensation, which tricks the brain into labeling the stimulus as external. By making the consequences of our own action unpredictable, therefore, the brain treats the self as another.

6.5.2. Force Prediction
You can see how we anticipate a stimulus and compensate for it, by attempting to estimate a force and seeing whether you can get that right.

6.5.2.1 In action
Use your right index finger to press down gently on the back of a friend’s hand. Your friend should then use her right index finger to press down on the same spot on your hand with the same force that she felt from your finger press. Continue taking turns at thisreproducing the same force each timeand you may notice that after about 10 turns, the forces of your finger presses are getting stronger.

Taken from : Mind Hacks

A Bright Future Awaits

The graveyard of memory research has turned into a fertile field budding with roses of all shapes and colors. The rose isn’t a bad analogy; while the final product will be extremely beautiful, you are likely to meet a few thorns along the way. In this book, I have reviewed our current knowledge base and laid out a comprehensive program to help you prevent memory loss due to the aging process, or to identify and treat mild memory loss if it has already set in. But all this is based on current knowledge, which is clearly limited in many ways. Given the various research directions that the field is taking, what does the future hold?
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CREB and Knockout Mice

A memory trace is solidified if there is a small gap in time between the pieces of information that need to be remembered. Using this technique, which is called spaced training, scientists engineered a fruit fly to have a photographic memory. In the same fruit fly species, they triggered a master gene called CREB, which has the ability to goad a number of other genes into action. In this manner, the fruit fly with a fabulous memory was born. Ideally, if we could stimulate CREB in the same way in
the human brain, total recall would become the standard for everyone. But there is no known method to turn a gene on or off in the human brain, so even though we all possess CREB, we don’t yet know how to galvanize it into action in people. The goal of these researchers is to see if manipulating CREB in some fashion will make it possible to unlock the full power of human memory.
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