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Alex Palazzo is a postdoctoral fellow working in the Department of Cell Biology at Harvard Medical School.


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« Are they really intronless? | Main | The latest on the Tonegawa incident »

N=3

Category: Science & Society
Posted on: November 20, 2006 10:15 AM, by Alex Palazzo

For biologists, this is the magical sentence. N=3. What does it mean?

Well lets say you perform an experiment. You want to see whether protein A binds to protein B. So you run to the lab, pipette away until the wee hours of the morning, prepare a sample, separate your proteins on a gel, probe for the proteins in question ... and you demonstrate that when you isolate protein A, protein B comes along for the ride. As a control, you perform the same experiment without protein A ... and sure enough there is no protein B in the isolated product. Great! But is it true? Perhaps you spit in your control sample destroying protein B. Perhaps a piece of lint fell in your test-tube? Maybe you mixed up the samples? How to tell? Repeat it. (I can just hear my thesis advisor now, "did you redo it?")

Many, many, many experiments have been only successfully done once never to be reproduced. These were probably what one would call artifacts. Others would say that the result wasn't robust or that the experiment gave variable results. This is also a reason NOT to tell your boss about a successful experiment BEFORE you've repeated it ... invariably those are the experiments that can never be reproduced. The Gold Standard for most experimentalists is "N=3" where "N" is the number of times that the experiment has been done successfully.

With that in mind I present to you the latest data captured by Youtube: Blender Induced Dog Rotation.

As you can see, blender activity seemed to activate rotation in this specimen of Canis familiaris. This observation was confirmed by three subsequent experiments (for a total of N=4). Thus it is clear that the blender does make the dog go round. Now the interpretation (i.e. that the dog is imitating the blender) has not yet been demonstrated.

Comments

1

If your time resolution is about 2 seconds, then it is not clear whether the dog is imitating the blender, or whether the blender is imitating the dog.

Posted by: Elia Diodati | November 20, 2006 2:59 PM

2

Or, perhaps the dog has been conditioned to spin when someone excited repeats "do it again, do it again!".

On a more "serious" side, does the dog do this because he's trying to figure out where the sound is coming from and spins to try to get a stereo lock?

Posted by: Phil | November 21, 2006 8:51 PM

3

My guess is that this is a bit like dogs who supposedly 'sing' when someone plays a harmonica. In actual fact they are howling because the high pitched noise is unpleasant to their ears. Similarly this dog reacts in his own agitated way to the high pitched blender sound.

Posted by: Jonathan | November 21, 2006 10:01 PM

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