Mr. Herndon. As I review the first polygraph chart I notice that I made a notation at 1 p.m., that Ruby’s attorneys agreed to let Mr. Ruby take the test. I actually started my adjustments of the instruments on Mr. Ruby at 3 p.m. In this regard, I believe it proper to state that I was using a Stoelting deceptograph model 22500 which utilizes three components, the pneumograph, the galvanic skin response, and the cardiograph. Also utilized during the examination was a Stoelting polygraph subject chair.
Mr. Specter. Will you describe the chair used during the course of this examination, please?
Mr. Herndon. The polygraph subject chair is so designed to adjust the level of the arms and to give complete and full support to the arms. This is necessary to provide a minimum of restriction or pressure on both of the arms of the examinee. This is desirable in order to obtain the best possible tracing with regard to a person’s relative blood pressure changes and relative changes in the heart rate. It is also desirable to obtain the best possible tracing of the electrodermal responses or the galvanic skin responses. The chair is also constructed so that the person will generally refrain from slouching or crossing his legs during the examination, both of which are undesirable.
Mr. Specter. Would you now then proceed to testify about the recordings on the chart?
Mr. Herndon. I also notice with regard to the room that the lighting in the room was incandescent and not fluorescent, this possibly being a factor in the tracings with regard to the galvanic skin response. The incandescent lighting is much preferable, and, therefore, I feel that there was no outside electrical disturbance with regard to the tracing of the GSR, galvanic skin response.
Mr. Specter. Could you elaborate just a little more on why you think the lighting would have an effect on the galvanic skin response testing device?
Mr. Herndon. I made a notation of this fact in my notes, in view of the fact that it has been evident in the past that fluorescent lighting at times has interfered with proper tracings with regard to the galvanic skin response.
Mr. Specter. And fluorescent lighting was present here?
Mr. Herndon. No, fluorescent lighting was not present here, and the desirable or preferable incandescent lighting was present.
Mr. Specter. So that that would have a beneficial effect on eliminating a potential source of interference?