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	<title>Maurits thinks aloud &#187; skepticism</title>
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		<title>Maurits thinks aloud &#187; skepticism</title>
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		<title>More Heartmath analysis</title>
		<link>http://maurits.wordpress.com/2006/02/22/more-heartmath-analysis/</link>
		<comments>http://maurits.wordpress.com/2006/02/22/more-heartmath-analysis/#comments</comments>
		<pubDate>Wed, 22 Feb 2006 13:21:41 +0000</pubDate>
		<dc:creator>maurits</dc:creator>
				<category><![CDATA[skepticism]]></category>

		<guid isPermaLink="false">http://maurits.wordpress.com/2006/02/22/more-heartmath-analysis/</guid>
		<description><![CDATA[In my previous analysis on the Heartmath article about predicting the future I already showed that with a very simple model it&#8217;s easy to predict that future, because of their faulty test set-up. I have given this some more thought and instead of running the simulation I derived mathematical formulas for the chance of predicting [...]<img alt="" border="0" src="http://stats.wordpress.com/b.gif?host=maurits.wordpress.com&blog=73044&post=17&subd=maurits&ref=&feed=1" />]]></description>
			<content:encoded><![CDATA[<div class='snap_preview'><br /><p>In my previous analysis on the <a href="http://www.heartmath.com/">Heartmath</a> article about predicting the future I already showed that with a very simple model it&#8217;s easy to predict that future, because of their faulty test set-up. I have given this some more thought and instead of running the simulation I derived mathematical formulas for the chance of predicting the future.<span id="more-17"></span></p>
<p>Remember that this is possible because they don&#8217;t use real random sequences. In an ideal random sequence you would only have 50 % chance of predicting that future, regardless whether it would be a calm or stimulating picture. No need for advanced math in that case.<br />
Ok, the formulas:</p>
<p>To predict the next picture this chance is 2/3*(7n ^2-n-1)/(3n-1)^2, where n is the number of stimulating pictures. In the limiting case (n going to infinity) this becomes 14/27, which is larger than 50%. This is already an important result, but things become even more interesting when we look at the difference between predictions of calm or stimulating pictures.</p>
<p>For calm pictures the chance is 5n^2/(3n-1)^2. For n going to infinity this becomes 5/9. and for the stimulating pictures the chance is (4n^2-2n)/(3n-1)^2. This is 4/9 for n going to infinity.</p>
<p>What we see here is a major difference in the chance of predicting the next picture. No wonder that with such a difference your brain (note carefully that I don&#8217;t say <em>heart</em> here) reacts differently, thus leading to a different heartrate. Would be nice if people would apply simple principles like <a href="http://en.wikipedia.org/wiki/Occam%27s_Razor">Ockam&#8217;s raisor</a> first, before thinking about holistic nonsense.</p>
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		<title>Randomness for dummies</title>
		<link>http://maurits.wordpress.com/2006/02/16/randomness-for-dummies/</link>
		<comments>http://maurits.wordpress.com/2006/02/16/randomness-for-dummies/#comments</comments>
		<pubDate>Thu, 16 Feb 2006 15:53:58 +0000</pubDate>
		<dc:creator>maurits</dc:creator>
				<category><![CDATA[Ramblings]]></category>
		<category><![CDATA[skepticism]]></category>

		<guid isPermaLink="false">http://maurits.wordpress.com/2006/02/16/randomness-for-dummies/</guid>
		<description><![CDATA[I just found a nice article (in Dutch). It describes an experiment from Ruper Sheldrake that &#8220;proves&#8221; that people know when they are stared at. In this article they debunk that experiment by showing that the test setup described by Sheldrake wasn&#8217;t actually that random at all. He has made the same mistake as the [...]<img alt="" border="0" src="http://stats.wordpress.com/b.gif?host=maurits.wordpress.com&blog=73044&post=15&subd=maurits&ref=&feed=1" />]]></description>
			<content:encoded><![CDATA[<div class='snap_preview'><br /><p>I just found a nice <a href="http://www.skepsis.nl/staren.html">article</a> (in Dutch). It describes an experiment from <a href="http://www.sheldrake.org/">Ruper Sheldrake</a> that &#8220;proves&#8221; that people know when they are stared at. In this article they debunk that experiment by showing that the test setup described by Sheldrake wasn&#8217;t actually that random at all. He has made the same mistake as the people from the <a href="http://www.heartmath.org/">Heartmath institute</a> that claim that your heart can predict the future. Look in one of my previous blogs for more details.</p>
<p>Oh, and if you want to be utterly bored, you can read Sheldrake&#8217;s articles <a href="http://www.sheldrake.org/papers/Staring/JCSpaper1.pdf">here</a> and <a href="http://www.sheldrake.org/papers/Staring/JCSpaper2.pdf">here</a>.</p>
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		<title>Can your heart predict the future?</title>
		<link>http://maurits.wordpress.com/2006/01/23/can-your-hart-predict-the-future/</link>
		<comments>http://maurits.wordpress.com/2006/01/23/can-your-hart-predict-the-future/#comments</comments>
		<pubDate>Mon, 23 Jan 2006 09:22:56 +0000</pubDate>
		<dc:creator>maurits</dc:creator>
				<category><![CDATA[Ramblings]]></category>
		<category><![CDATA[skepticism]]></category>

		<guid isPermaLink="false">http://maurits.wordpress.com/2006/01/23/can-your-hart-predict-the-future/</guid>
		<description><![CDATA[Of course not! But according to this article from the  Instute of HeartMath it can. Your heart rate reacts on events that take place about 4.5 seconds later. Now before you get enthousiastic over this and get visions of making fortune in the casino with a simple heart rate monitor, let me share my [...]<img alt="" border="0" src="http://stats.wordpress.com/b.gif?host=maurits.wordpress.com&blog=73044&post=6&subd=maurits&ref=&feed=1" />]]></description>
			<content:encoded><![CDATA[<div class='snap_preview'><br /><p>Of course not! But according to this <a href="http://www.heartmath.org/research/research-intuition/Intuition_Part1.pdf">article</a> from the  <a href="http://www.heartmath.org/">Instute of HeartMath</a> it can. Your heart rate reacts on events that take place about 4.5 seconds later. Now before you get enthousiastic over this and get visions of making fortune in the casino with a simple heart rate monitor, let me share my opinion on this subject with you. First I will explain their test setup.</p>
<p>Each participant gets to see a series of 45 pictures. In this series there is a change of 2/3 of an calm picture and 1/3 of an emotional (violence, sexual content, etc.) picture. The participant first clicks on a button and then 6 seconds later either a calm or emotional picture appears. And the `suprising&#8217; part is that the heart already knows about 4.5 seconds in advance which of the two types of pictures this is going to be. Amazing!</p>
<p><span id="more-6"></span></p>
<p>However, there are two minor problems. First the heart doesn&#8217;t predict the future always correctly. The correlation between the heart rate and the shown picture is quite small. However, it&#8217;s still somewhat significant and for winning lots of money in the casino it would probably be enough. There is another problem: in their test setup they don&#8217;t show the pictures completely randomly. They always put in exactly 15 stimulating pictures and 30 calm pictures. So you will never have a sequence of 45 calm pictures. This severely limits the amount of possible sequences. And what&#8217;s worse, this makes it possible to predict the future  with a very simple strategy. After a few pictures the human brain will see a pattern and could for example come up with the following simple scenario: after every emotional picture there is quite a large chance of seeing a calm picture. After a single calm picture comes another calm picture. After two calm picture comes an emotional picture. In other words: the brain learns about the distribution of calm and emotional pictures.</p>
<p>If the pictures would be completely random then this strategy wouldn&#8217;t work very well. You would have 50 % chance of guessing the next picture. This won&#8217;t get you rich. However, with their test setup your chances increase! A brute force calculation on all the possible sequences shows that the odds have increased to 54 %. And this is exactly in the same order of magnitude as the correlation that was mentioned in the article. There are two more things left for me to do: first I would like to derive a mathematical formula for the chance of predicting the right picture. And secondly, I want to see if there&#8217;s a difference in predicting emotional pictures versus calm pictures.<br />
My conclusion so far: your heart can&#8217;t predict the future and your brain can&#8217;t be that easily fooled.</p>
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