抄録
The Concealed Information Test (CIT) assesses whether an examinee knows a crime-related item on the basis of response differences between crime-relevant and crime-irrelevant items. One of the effective measures in the CIT is respiratory speed. The respiratory speed has been defined as an average of moving distances of respiration curve in a specified time interval after the item onset. This moving distance differs between parts of a respiratory cycle. Therefore, the calculated respiratory speed is disproportionately affected by how the parts of the respiratory cycles are included in the time interval. To resolve this problem, Matsuda and Ogawa (2011) proposed a weighted average method. This method calculates the respiratory speed per cycle and weighs it with the proportion that the cycle occupies in the time interval. In the present study, we applied the weighted average method to the calculation of the inspiratory and expiratory speed. Using the weighted average method, the discrimination performance of the inspiratory/expiratory speed descriptively increased as compared with using the original method. However, as for the expiratory speed, statistical tests did not find significant differences between the original and weighted average method. These results raise the next issue: The detection method of respiratory cycles should be more sophisticated.
