The 10 dB, or was it 20 dB, claim could be a case of "belief preservation" as described in section 3.5 of the paper *Teaching Critical Thinking: Lessons for Cognitive Science*, by Tim van Gelder
http://frank.itlab.us/forgetting/teaching_critical_thinking.pdf Dave WX7G _______________________________________________ Topband reflector - topband@contesting.com
