The Australian didgeridoo or yidaki is a simple wind instrument, yet a good player can coax from it a variety of timbres greater than that of many an orchestral instrument. It can produce a huge variety of different timbres, despite it usually playing only a single note. A study of the vocal tract and lip contortions necessary for this feat tells us a lot about how music is made.

To understand this phenomenon, researchers led by Joe Wolfe of the University of New South Wales in Sydney simultaneously measured the sound produced by the didgeridoo and the acoustic impedance of the player’s vocal tract. What they found was that a skilled player alters the acoustics inside their mouth to set up strong resonances at certain frequencies. Players enhances certain frequencies while inhibiting others, much as different vowel sounds are produced by adopting different positions for the tongue and vocal cords. In other words, experienced players are using their glottis to accentuate the instrument’s tonal variation.

Skilled didgeridoo players do this subconsciously, Wolfe says: “None of the players to whom we’ve spoken is aware of it.” But the creation of these characteristic frequency bands, called formants, is what gives their playing expression and variety. “It’s easy to make a basic sound,” Wolfe says. “Then you have to learn circular breathing. Learning to make strong formants takes a while. Other techniques involve vocalizing and playing at the same time: one gets interactions between the vibrations from the lips and from the vocal cords.”

via news@nature.com, PhysOrg, Acoustics: The vocal tract and the sound of a didgeridoo (Abstract)

Why I blog this? Over the past few months I have been learning about as much as I can take in about acoustics, synthesizers, and music in general, so this article instantly grabbed my attention. Also, a good friend of mine has been playing didg for a number of months now, and I have been able to watch the dramatic improvement in her playing skills during that time. Thus, this story about the acoustics of the didgeridoo was quite interesting to me.

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 Tags: didgeridoo, acoustics

Reactive Colours is an innovative project that is developing software to promote enjoyment and social interaction in severely autistic children.

It is using an non-commercial open source development model, and is aiming to include the autistic and Asperger’s community as developers and contributors to the project.

Sounds great. I’ve highlighted some of Mind Hacks interview with project leader Wendy Keay-Bright.

Wendy undertook a feasibility study which strongly indicated that this therapeutic way of working with computers could have particular resonance for children on the autistic spectrum.

The design of the software prioritises the computer as a medium. The computer becomes an environment where exploration and play, which are vital in the learning process, can occur spontaneously. This contrasts with the generally accepted notion that the mouse, keyboard, screen and even programming code, are purely functional components in a system.

Many computer programmes for autistic children focus on task or making progress, and this in some cases, can lead to the feeling of failure or children can become ‘locked in’ to a task and resist communication with others.

A highly significant goal in autism education is the achievement of joint attention tunnels. With this in mind it has been encouraging to witness children share their Reactive Colours activity session (which we are calling ‘Reactivities’) with their peers in monitored classroom environments.

This has been most dramatic in a multi-sensory environment using the interactive whiteboard where children use their hands and bodies to choreograph stunning visual effects.

Multi sensory stimuli can be alarming for some children, however the Reactivities reward touch and sound with simple forms - colour, shape and words and deliberately avoids sensory overload.

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High levels of anxiety are very commonly found in children on the autistic spectrum. The experience of playing with Reactivities on the computer is entirely intuitive; the reactive graphics focus on spontaneous mark-making and cause and effect.

Expressive mark-making can relieve tension and outwardly represent inner experiences. Rhythm, sound, space, velocity, colour, shape and movement are created and controlled by the individual as they experiment with the mouse, keyboard and microphone input devices. This expression of creativity is personal, unique and ultimately satisfying.

Children are content to choose and explore, take turns and co-operate with others, all of which are significant for individuals on the autistic spectrum. The capacity to have fun is an almost universal human coping mechanism for dealing with stress, however for many autistic children this vital tool for releasing energy is not realised.

From our early experience of developing Reactive Colours with young autistic children we have seen opportunities for structured and parallel play that may help to create a calm environment for participatory learning.

And a note:

Although the Reactive Colours website has not yet been officially launched, (we are aiming to do this Spring 2006 when the Reactivities have been completely iterated with users) we would encourage anyone interested in the project to post their details on the forum and visit the site regularly for updates.

Teachers, parents and advisors who would like to participate in evaluating the prototype software can email Wendy for more information.

But Reactive Colours does have a blog.

Why I blog this? I met a women on Friday night who works with two autistic children. I asked her a number of questions about how these children experience the world. I was trying to figure out how technology could help these children, or help her help these children even more than she already is. So when I stumbled across the Reactive Colours project today, I knew it made sense to make a post and pass this information on to her and all of my other readers.

Olivier Toubia, a Ph.D. candidate at the Marketing Group (MIT) has an article (PDF) on Idea Generation, Creativity, and Incentives.

Idea generation is critical … However, there has been relatively little formal research on the underlying incentives with which to encourage participants to focus their energies on relevant and novel ideas.

This paper examines whether carefully tailored idea generation incentives can improve creative output.

Toubia used three types of incentives to trigger idea generation:

• A Flat condition where participants got $10 for showing up,
• An Own condition where participants got $3 for every idea they submitted, and
• An Impact condition where each participant got $2 for each time an idea they submitted built on one of their previous ideas.

See the sift everything experiment for a graph of the results.

Why I blog this? Because, as Jeremy says, “There is a lesson here for entrepreneurs regarding individual effort. If you can’t spend this kind of time [>20 hours], how can you hope to come up with deep, novel, thought-provoking ideas?”

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 Technorati Tags: Creativity, Ideas, Idea Generation, Incentives, Management Science

The human brain has access to a massive amount of visual sensory data. Researchers have conducted some interesting studies to figure out how our brain decides what small window of that data we direct our attention to. The researchers determined that when we notice an object appearing, we pay attention to it for an extended period of time (1/3 of a second). But, when we notice an object disappearing we immediately direct our attention elsewhere.

[The appearing object effect] was first observed by Michael Posner — if an object appears in one part of our field of view, it temporarily delays our ability to detect another object appearing near it. The effect begins about a third of a second after the first object appears and lasts about a second. If the second object appears sooner than that, we actually notice it quicker. Subsequent research revealed that the effect became progressively smaller at greater and greater distances from the spot where the first object appeared — surprisingly, we’re quicker to spot other objects appearing farther away from the original object.

See Cognitive Daily for the full article, including the research on disappearing objects.

Recent research at the California Institute of Technology has confirmed that an area of the human brain, the ventrolateral prefrontal cortex (vPF), is involved in the planning stages of movement. The planning stages of movement happen during the instantaneous flicker of time when we contemplate moving a limb. This has implications for the development of brain-machine interfaces for the paralyzed as well as for able-bodied people who may seek to augment themselves with such technology. According the press release, the work currently appears in the online version of Nature Neuroscience. I do not subscribe to Nature so unfortunatly I can not access this paper.

“We were looking for the brain regions that may be contributing to planned movements. And what I was able to show is that a part of the brain called the ventrolateral prefrontal cortex is indeed involved in planning these movements.” Just by analyzing the brain activity from the implanted electrodes using software algorithms that he wrote, Rizzuto was able to tell with very high accuracy where the target was located while it was on the screen, and also what direction the patient was going to reach to when the target wasn’t even there.

Why I blog this? Practical consumer/amateur level brain-computer interfaces, with at least rudimentary functionality, are within reach. Obviously implanted electrodes are not practical for most people, but research is advancing in all directions. So, if we do get external BCI’s, even if they act simply as a new form of mouse, they will still be very hot technology to play with. I try to keep somewhat up to date on developments in this field.

via Caltech Press Release - Scientists Discover What You Are Thinking, March 16, 2005
via KurzweilAI.net

How much can we understand about human motion using only simple cues? Take a look for yourself using BioMotionLab1.6, a flash-based visual demonstration developed by an international team of researchers headed by Prof. Dr. Nikolaus Troje. Adjust four different sliders (male/female, heavy/light, nervous/relaxed, and happy/sad) to change the motion of the dots. It is amazing how much the human mind can ‘read’ from the motion, even though only minimal data is presented. I played around with it for a few minutes and found their simulation to be a fairly elegant examination of human movement using such a small number of points.

Dr. Troje holds a Canadian Research Chair in Vision and Behavioural Sciences. The Biomotion lab operates out of two locations: Queen’s University in Kingston, Ontario and Ruhr-University in Bochum, Germany.

From the Biomotion lab site:

We are working on several aspects of visual perception and cognition. Our major interest is focused on questions concerning the biology and psychology of social recognition. That is: conspecific recognition, gender recognition, individual recognition, recognition of an agent’s actions, intentions, and emotions and personality traits.

In the past, we had mainly worked on the psychophysics and modelling of human face recognition. More recently, our focus shifted towards perception of biological motion as a major source of social information.

The goal of our current work is to provide a solid basis for the description, analysis and synthesis of animate motion patterns. We want to achieve a comprehensive understanding of the information transmitted through biological motion, its perception and underlying neuronal mechanisms. In addition to human psychophysics, we are using the pigeon as a model for ethological and neurophysiological investigations in the context of courtship behaviour, social learning, and social fascilitation.

The procedure they used to create the display will be described in detail in a forthcoming paper submitted to the Journal of Vision. Troje, N. F. (submitted) Decomposing biological motion: A framework for the analysis and synthesis of human gait patterns.

Why I blog this? I referenced it in my Cybernetics and Society (STV205) class, but was unable to actually demonstrate the visualization because I did not have a computer available at the time. To anyone from class who was interested - Enjoy :)