23857122-0457-180273-0387

CN Seb we ar VAD Engineering Division Memorandum Report Noe MCREXD=69)-18D 26 April 1919 APPENDIX A PSYCHOLOGICAL ANALYSIS OF REPORTS OF UNIDENTIFIED AERIAL OBJECTS The Inaccuracy of Human Observation Psychologists have long know that human perception is fallible. In fact, part of the science of psychology is concerned with the measurement of errors of observation, amd with the discovery of the conditions and laws that govern such phenomena. Errors of observation may be classified as variable or constant. Variable errors are those in which a mmber of separate observations are found to differ from one another, The distribution of such errors often follows the normal probability curve. Constant errors are those in which observations are consistently biased in one or another direction, For exemple, individuals often are rpuilty of a eonstant orror, in the direction of underestimation, in reporting thelr arose Errors of observation may be olassified further as precision errors and identification errors, Inacouracy in estimating the speed of an aircraft is an example of the former, Mistaking an aireraft for a "flying saucer" is an exemple of the latter. it is the purpose of the present report to analyze 212 reports of observations of unidentified flying objects in order to see to what extent these reports oan be explained in terms of known psychological facts and principles. Scientific Method and a Posteriori Data A word of caution mest be injected at the outset of this report, Certain conditions are necessary for drawing valid scientific eaclusions. GO Ms 2-0 8 8S TAL Declassification Authority: NND 57565