TweetFollow Us on Twitter





[IMAGE p70-71_Dave's_Column_htm1.GIF]

I just learned about a technique for graphically representing points in n-dimensional space, first presented in 1973 (I guess I'm a little behind) by a Harvard statistician, H. Chernoff. Representing points in two or three dimensions is pretty straightforward, but what about data points in, say, ten dimensions? Chernoff's approach was to use cartoon faces, with each dimensional parameter determining a facial feature. One parameter determines eye size, for instance; another regulates eyebrow slant, another determines the position of the mouth, and so on. I was struck dumb by the power of the idea. Humans have a built-in feature integration and recognition ability that lets us intuitively track and correlate changing facial features with no conscious effort, and Chernoff's technique elegantly capitalizes on this ability.

The possible uses for these "Chernoff faces" are many and varied. In his book Computers, Pattern, Chaos, and Beauty , Clifford Pickover talks about a number of possible applications: the elucidation of high-level statistical concepts, uses in air traffic control and aircraft piloting, educational applications, and many more. In one particularly illuminating example he uses the faces to characterize sound. He runs the sound data through an auto-correlation function (for the gory details, see his book) and then uses the first ten points of the resulting data set to control the faces. As examples heshows the faces generated by the sounds s , sh , z , and v , sounds which are very similar. The resulting faces, though, are easily and immediately distinguishable. As Pickover points out, this correlation between sounds and appearance of the faces immediately suggests the possibility of using the faces as feedback devices for helping severely hearing-impaired people to modify their vocalizations. To learn a particular sound, they would try to produce the same Chernoff face as that produced by a hearing person vocalizing the sound.

There are a few things worth noting about these faces. First of all, children respond just as well as adults to the faces. Since facial recognition capabilities develop in infancy, that's really not surprising, but it does mean that the faces have very broad application possibilities. I'd also bet that they're freer of cultural bias than many interface elements, which broadens their possible uses even more. Second, the faces probably aren't appropriate for quantitative analysis; if you need to get the exact value of a parameter, use a gauge. But they're great for high-level cognitive discrimination, especially for tracking qualitative changes in multiple variables through time. Third, because they're human faces, they could contain emotional connotations that have nothing whatever to do with the data they represent. Imagine a face used to track water levels and pump pressures in a nuclear power plant getting happier and happier as the plant approaches meltdown. Time for some facial calibration, I'd say.

Included on the Developer Essentials CD is my version of Pickover's face routine. It takes as arguments a pointer to a rect and a pointer to an array of 10 bytes, and it draws the resulting face in the current port, scaled to the rect. See the code for more details. One really cool thing is that if ten dimensions aren't enough, you can simply add more detail to the picture: hair maybe, or ears. The hardest part is coming up with meaningful 10-D data.

What's really interesting is how this technique and others like it capitalize on the kind of processing that we already do automatically: you don't have to learn to discriminate faces; you already know how, and you do it without even trying. So even while some part of your brain is busily integrating facial features, your conscious mind is still free to deal with other, higher-level tasks. All the best interfaces do this to some degree, by simulating some part of what we call reality. (For instance, everyone's favorite desktop model simulates a flat, bounded environment with overlapping two- dimensional areas, something we're very familiar with in the real world through our interactions with tabletops and paper.) A convincing simulation, or even one that captures essential parts of the reality (like the Macintosh desktop), is an incredibly powerful thing.

Human interfaces (so far humans are the predominant, market-driving users of computers) can take advantage of many things: our ability to maintain internal mental maps, our built-in image processing, our kinesthetic awareness of space, and so on. All these things have been finely tuned by a zillion years of evolution, so why not use them? Effective human interfaces are overwhelmingly visual and tactile, precisely because vision and touch are the primary senses we use to interact with the world we know so well. (For a dog I suppose a good interface would have to be heavily auditory and olfactory:

sniff a file to get info; when something you search for is found, it whines so you can locate it; system errors smell like flea shampoo.)

New interfaces are trying to capitalize even further on what we already know how to do. Xerox PARC's latest experimental interface, the Information Visualizer, uses 3-D real-time animation and represents information as directly manipulable 3-D objects. You can "pick up" a data structure and look at it from all angles, using your built-in spatial skills to help make sense of large bodies of information. PenPoint, Go Corporation's recently announced pen-based operating system, takes advantage of, among other things, our familiarity with pencils and notebooks. (I guess it's not recent anymore, is it? It's still February in here.)

The goal of an interface is to make using the computer easier and more intuitive. What more direct way than to simulate on the computer things that people already know how to work with? A really interesting question is whether simulation is a necessary part of a good interface, but it's a question without an answer yet, at least as far as I know. In the meantime, while you're programming your next whiz-bang interface, remember to occasionally look beyond the next crash or whether you remembered to unlock that handle. There are many, many things that all people are already good at: take advantage of them.


  • Computers, Pattern, Chaos, and Beauty by Clifford A. Pickover (St. Martin's Press, 1990).
  • A Monster Is Bigger Than 9 by Claire and Mary Ericksen (The Green Tiger Press, 1988).
  • Byte , February 1991.
  • Anything by Bruce Tognazzini.

DAVE JOHNSON, our technical buckstopper, has been with Apple for three years. Before becoming an official stopper-of- the-buck, he worked on PostScript printers in Apple's software testing group. His interest in computers dates back to his college days at Humboldt State University, where he majored in energy systems engineering, and minored in everything else he could think of (it was a seven-year stay). He's also our resident juggler, who will juggle anything or anybody--and has. Actually, Dave has always been a show-biz kind of guy; as a kid, he was into monster makeup, which led him to monster-making and puppeteering at Lucasfilm's Industrial Light and Magic. (You've seen his work in such flicks as Spaceballs , The Witches of Eastwick , and Inner Space ; he was also an On-Set Duck Mechanic for Howard the Duck .) When not buckstopping and juggling, he programs the Macintosh (screen savers, gratuitous fractal programs, artificial life simulations: nothing useful), hangs out with his wife and dogs, reads as much as possible, and pushes all available limits, both real and imagined.*


Community Search:
MacTech Search:

Software Updates via MacUpdate

Typinator 6.7 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
Adobe Lightroom 6.2 - Import, develop, a...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
ForeverSave 2.1.4 - Universal auto-save...
ForeverSave auto-saves all documents you're working on while simultaneously doing backup versioning in the background. Lost data can be quickly restored at any time. Losing data, caused by... Read more
VueScan 9.5.27 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
AirPort Utility 6.3.6 - Set up and manag...
Note: Most recent release available only within OS X 10.11 El Capitan update. Use AirPort Utility to set up and manage your Wi-Fi network and AirPort base stations, including AirPort Express, AirPort... Read more
Quicksilver 1.3.1 - Application launcher...
Quicksilver is a light, fast and free Mac application that gives you the power to control your Mac with keystrokes alone. Quicksilver allows you to find what you need quickly and easily, then act... Read more
Tidy Up (Five Users) 4.1.5 - Find duplic...
Tidy Up is a complete duplicate finder and disk-tidiness utility. With Tidy Up you can search for duplicate files and packages by the owner application, content, type, creator, extension, time... Read more
Mellel 3.4.3 - The word processor of cho...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
Skype - Voice-over-internet p...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
Bookends 12.6.0 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Access the power of Bookends directly from Mellel, Nisus Writer Pro, or MS Word (... Read more

Swords & Crossbones: An Epic Pirate...
Swords & Crossbones: An Epic Pirate Story 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »
Camel Up (Games)
Camel Up 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Martian: Bring Him Home (Games)
The Martian: Bring Him Home 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Based on the best selling novel and critically acclaimed film, THE MARTIAN tells the story of Astronaut Mark... | Read more »
This Week at 148Apps: September 21-30, 2...
Leap Into Fall With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above... | Read more »
Tweetbot 4 for Twitter (Social Networki...
Tweetbot 4 for Twitter 4.0 Device: iOS Universal Category: Social Networking Price: $4.99, Version: 4.0 (iTunes) Description: *** 50% off for a limited time. *** | Read more »
Mori (Games)
Mori 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Stop, rewind and unwind with Mori. Time is always running, take a moment to take control. Mori is an action puzzle game about infinitely... | Read more »
100 Years' War (Games)
100 Years' War 1.0 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Tower in the Sky (Games)
Tower in the Sky 0.0.60 Device: iOS Universal Category: Games Price: $1.99, Version: 0.0.60 (iTunes) Description: | Read more »
hocus. (Games)
hocus. 1.0.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0.0 (iTunes) Description: New, polished, mind-bending, minimal puzzle game with dozens of levels and extra-ordinary design Features:- Beautifully crafted... | Read more »
Mos Speedrun 2 (Games)
Mos Speedrun 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Mos is back, in her biggest and most exciting adventure ever! Wall-jump to victory through 30 mysterious, action packed levels... | Read more »

Price Scanner via

13-inch 2.5GHz MacBook Pro (refurbished) avai...
Apple has Certified Refurbished 13″ 2.5GHz MacBook Pros available for $829, or $270 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook Pros... Read more
27-inch 3.2GHz iMac on sale for $1689, save $...
Adorama has the 27″ 3.2GHz iMac on sale for $1689 including free shipping plus NY & NJ sales tax only. Their price is $110 off MSRP. Read more
12-inch Retina MacBooks on sale for up to $12...
B&H Photo has 12″ Retina MacBooks in stock today and on sale for up to $120 off MSRP. B&H will include free shipping, and there is NY sales tax only: - 12″ 1.1GHz Gray Retina MacBook: $1224 $... Read more
Tablets Shaping Up for Growth in 2016 – Strat...
Observing that Apple, Samsung, and Microsoft have refocused what tablet computers can do, market analysis firm Strategy Analytics believes there is immense opportunity for new and replacement sales... Read more
Apple Interbrand’s Number One Most Valuable G...
Apple and Google hold aced #1 and #2 spots respectively in Interbrand’s 2015 Best Global Brands Report, leading all tech brands that now comprise more than a third of the entire rankings value.... Read more
Apple offering refurbished 2015 13-inch Retin...
Apple is offering Certified Refurbished 2015 13″ Retina MacBook Pros for up to $270 (15%) off the cost of new models. An Apple one-year warranty is included with each model, and shipping is free: -... Read more
Apple refurbished 2015 MacBook Airs available...
Apple has Certified Refurbished 2015 11″ and 13″ MacBook Airs (the latest models), available for up to $180 off the cost of new models. An Apple one-year warranty is included with each MacBook, and... Read more
Adobe Photoshop Elements 14 Gets Haze Removal...
The latest iteration of Adobe’s powerful consumer image editing appliction Photoshop Elements 14 analyzes your photo and removes background haze, so your shot looks sharp all the way to the horizon... Read more
Apple refurbished 15-inch Retina MacBook Pros...
Apple has Certified Refurbished 2015 15″ Retina MacBook Pros available for up to $380 off the cost of new models. An Apple one-year warranty is included with each model, and shipping is free: - 15″ 2... Read more
21-inch iMacs on sale for up to $120 off MSRP
B&H Photo has 21″ iMacs on sale for up to $100 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1029.99 $70 off - 21″ 2.7GHz iMac: $1229 $70 off - 21″ 2.9GHz iMac: $... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're Read more
Senior Payments Architect - *Apple* Pay - A...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments architect to join the Apple Pay Engineering team. You will Read more
SW QA Engineer - *Apple* TV - Apple (United...
**Job Summary** The Apple TV team is looking for experienced Quality Assurance Engineers with a passion for delivering first in class home entertainment solutions. **Key Read more
Finance Manager, *Apple* Online Store - App...
…successful global retailer. Innovate and think creatively as a finance partner for the Apple Online Store team. Look ahead and anticipate the needs of your business. Read more
*Apple* Retail for Business Support Supervis...
…is looking for a motivated, outgoing, and creative individual who wants to offer Apple Business Customers an unparalleled customer experience. The Apple Retail for Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.