Teaching Through Testing

Last weekend, President Obama declared that students take too many standardized tests and noted that "our kids should only take tests that are worth taking, tests that are high quality, aimed at good instruction and make sure everybody's on track."

While many educational experts have decried the practice of "teaching to the test" as counter productive and creatively stifling, I feel that there isn't enough discussion of the positive value of teaching through testing.

Our brains are designed to learn the things we encounter frequently.  Each time our neurons fire to retrieve a piece of information, that neural pathway is strengthened making it easier to remember the next time that data is needed. Learning happens most effectively when we are triggered to retrieve the information at regular intervals.

Tests provide a valuable service by determining the areas where our knowledge has gaps and identifying where to focus our study efforts.  They also provide an even more valuable role in providing opportunities to retrieve information frequently enough to enhance the learning process.

Test for enhancing learning should occur often and have low stakes. A variety of different types of tests should be used to nurture multiple learning methods. According to the educational author and blogger Annie Murphy Paul, "testing should inculcate a growth mindset in students by demonstrating that ability grows through exerting effort and making mistakes."

Paul has labeled the type of testing that she encourages as Affirmative Testing and has developed a course to teach educators how to do it well. I encourage you to read her Affirmative Testing Manifesto. 

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Learning by Observation

Long before any of us understand language, learn to read, or attend school, we have learned a great deal about the world by drawing conclusions from our direct observations. No matter how much knowledge we absorb, we continue to draw new conclusions from our direct experience.

In 1686, Sir Issac Newton published four rules of scientific reasoning in his Principia Mathematica. These rules are essentially how we interpret and generalize from experience whether or not we are conscious of the process. Rather than use Newton's terminology, I am going to interpret these in my own words.

Find the Simplest Explanation

We don't like complexity.  As soon as we find an explanation that appears true and a reasonable explanation, we are content with that answer and stop looking for another explanation.

The Causes are Always the Same

Once we decide that a result is caused by an event, we assume that every time we see that result, it was caused by the same event.

If it is True in our Experience, it is a Universal Truth

Each situation we encounter is new, but we need to decide how to approach it based on our previous experience. If we have seen an event trigger a result in the past, we expect it to trigger the same result this time and every subsequent time.

We are Right Until Proven Otherwise

Once we believe we understand how something works, we are confident that understanding is correct until we see an incident that directly contradicts our conclusions.

These four rules of reasoning are an essential part of our human nature and the reason we are able to learn so much, so quickly. They are also the fundamental underpinning of science. But they also explain why we are so prone to jumping to incorrect conclusions and why it can be so difficult to change our minds once we make a conclusion.

As a child, our understanding of the world is simple and naive. As we have greater experience, our understanding gains nuance as we try to understand the increasing complex interactions we have with others. Our ability to learn from conversation with others, reading, and watching video allows us to expand our understanding beyond our own personal experiences.

At each step, we need to fit the new knowledge into our existing model of how the world works. And at every stage of life, we think we understand things better than we actually do.

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Cameras of the Future

Historically, there has been a direct relationship between the size of a camera and the quality of the images that it can capture. Sharper, brighter images were the result of larger lenses to collect light and larger sensors to convert that light to a digital image. Computational imaging ends that relationship.

The L16 is a new camera from Light that packs 16 individual 13 megapixel sensors with three different focal lengths into a size slightly larger than a smartphone. Five of the sensors have a 35mm lens, five have a 70mm lens and six have a 150mm lens. By capturing ten images, simultaneously, at the different focal lengths and different locations on the camera, the device collects data that can be computed into a 52 megapixel image.

While the L16 provides the resolution of a high quality DLSR in a much smaller package, at $1699 the price seems a bit steep to cause many people to rush out and replace their existing DLSR.  However, as the technology progresses and comes down in price, I believe this will be the way most new cameras will be designed.

Light is also working with phone manufacturers to bring the technology into smartphones by late next year.

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The Revelation of Sonmi 451

This weekend I saw the movie Cloud Atlas for the first time. And the second time.

As I watched the complex interplay of six stories linked across time, I was entranced by the strength of the cast, the power of the story and the beautiful cinematography. When it was over, I felt enchanted, but more confused than enlightened. I certainly wanted to see it again soon.

Watching the movie a second time the following evening, the relationships between the stories were easier to see and I realized how much the cuts between the stories clarified the overall message. The directors, Andy and Lana Wachowski and Tom Tykwer have created a film that will become a science fiction classic even though it did not do well at the box office.

Perhaps the best summary of the interplay between the stories is voiced by one of the main characters in the Revelation of Sonmi 451:

"To be is to be perceived, and so to know thyself is only possible through the eyes of the other. The nature of our immortal lives is in the consequences of our words and deeds, that go on and are pushing themselves throughout all time. Our lives are not our own. From womb to tomb, we are bound to others, past and present, and by each crime and every kindness, we birth our future."

If you are a science fiction fan and haven't seen Cloud Atlas yet, you should watch it soon. At least once.

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Facebook is Preparing us for Virtual Reality

Last week's announcement by Facebook that they are adding support for 360 degree video and the release of the 360 degree Star Wars video are certainly intended to help prepare us for the upcoming release of the Oculus Rift virtual reality headset.

I watched the video on my desktop computer which is a different experience than a fully immersive headset. You can look in any direction and see what is happening by dragging the screen with the mouse, but I am sure it would feel more natural if the direction of view happened automatically when I turned my head.

However, I question whether video can ever be a fully immersive experience. While it is interesting to be able to look in different directions, in the real world you could also change the speed and direction of travel. Changing the direction of view only leaves me with the feeling of being an observer rather than a participant.

What are your feelings about the 360 degree video capability?

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