If a person places his ear against the hard surface of a door in an attempt to overhear what people may be talking about behind the door, the eavesdropper may well leave an impression of his ear on the door's surface--an impression that can be "developed" much like a latent fingerprint at a crime scene can be made visible. 

There are persons in crime laboratories who assume that the human external ear characteristics are unique to each individual and unchanging during the lifetime of an adult. Some have gone as far as to suggest that such individuality can also be used to identify persons with the same degree of confidence with which latent fingerprint examiners make a "positive fingerprint identification." A few go even further and suggest that the "suspect" who left a latent ear impression can be identified by comparing the latent print to ear prints of known individuals. 

There is, however, no empirical data to date that proves the underlying premise: that the ears of a human being are in fact so different and distinguishable that their detail is never duplicated. The only (non-scientific) argument in support of ear individuality that has been forthcoming is always a reference to the familiar saying that "nature never duplicates itself" or that "all snowflakes are different."

If we postulate that a case for human individuality could conceivably be made, [and such a case has already been made in thecase of identification by fingerprints and by DNA--excepting identical twins who have the same DNA] that does not answer the question whether the purported individuality can also be established reliably solely by an examination of the outside shape and characteristics of the human ear. But even if we were to find that human ears, when studied in all their detail, are different from person to person, it will still require a significant further leap to also conclude that such individuality can be established reliably by looking at an incomplete and partially blurred reproduction of an ear such as might be visible in a "latent" ear impression.

Yet, the premise is sufficiently intriguing that it deserves a serious inquiry. For that purpose, on the following pages is contained a draft of a preliminary proposal for "ear uniqueness" research that might provide us the answers which we are seeking to find. We would appreciate interested persons to examine this proposed draft and send us comments for improvement as well as guidance on how the proposal could be implemented.

Introduction

Over the years, suggestions have been made in the occasional literature that the shapes and characteristics of the human ear are widely different and may be in fact sufficiently variant that it is possible to differentiate between the ears of all individuals. Unfortunately, this "individuality" has apparently been taken for granted (the "snowflake" phenomenon) but has never been empirically established. There is not a single published scientific study that establishes that ears are in fact different and distinct and that such individuality can be verified through comparison. Perhaps a major reason for such deficiency is that most persons advocating ear individuality, while well intentioned and full of enthusiasm and energy, lacked a serious understanding of what is needed to conduct empirical investigations. Most advocates of uniqueness and individuality have not been trained in the scientific method and gained their own experience in other identification techniques through "on-the-job" experience and instruction by persons with a similar background. 

The purpose of the study described herein is to inquire in the characteristics of human ears for the purpose of exploring whether they can be used for human identification.

Overview of the Study

The descriptive title of this preliminary proposal contemplates a multi-disciplinary approach to conduct research into the individuality of human ears in accordance with accepted standards for scientific research. The initial steps that the research project envisions are subject to revision at any time after an investigatory team has been formed and preliminary findings become available. The following four initial steps are contemplated by the Project:

STEP # 1: To assemble a Research and Investigative Team. It is contemplated that the Research Team will consist of: two forensic physical anthropologists; two anatomists; two to four law enforcement criminalistics specialists; and one coordinator and project leader. This Research and Investigative Team will hereinafter be referred to as the Research Team.
 

STEP # 2: To convene the Research Team for the purposes of (1) familiarizing the participants with the occasional literature and accumulated experiences on "ear identification" that have been placed on the public record to date; (2) refining the parameters of the research project as outlined in this document; (3) establishing a common and accepted nomenclature for the study of ears; (4) devising a uniform method for the assembling, storing, and studying of a photographic collection of human ears; (5) soliciting the cooperation of all individuals currently in and out of law enforcement who have worked with "ear identification" cases; (6) adding such additional goals, procedures, and protocols to this document as the Research Team in its collective wisdom decides are essential and/or desirable.

STEP #3: Selecting a Field Support Team for Investigation and the Collection of Data. This team, which will hereinafter be referred to as the Investigative Group, will consist of approximately twenty law enforcement officers and a similar number of law students, geographically situated throughout the United States, who will, jointly or individually, be charged with the duty of collecting ear photographs from among the general population according to the protocol devised in Step #2. It is anticipated that the Investigative Group will collect ear photographs of approximately 10,000 adult (age 20 or older) individuals nationally, of which it is expected that approximately 4,000 will be of a predominantly Caucasian racial origin, 4,000 of a predominantly Negroid racial extraction, and 2,000 of Mongoloid or mixed racial characteristics. After study of the data collected, the Research Team will evaluate whether a collection of 10,000 human beings’ ear photographs is a sufficient sampling of the population to arrive at a valid preliminary statistical analysis of the characteristics and variability of the human ear. At the conclusion of Step #4, the sufficiency of this data base will be re-examined.

STEP #4: Convening the Research Team to engage in the following tasks: (1) adding to the Team two academically trained Statisticians (Ph.D. level); (2) devising a protocol for study and classification of the assembled data base; (3) classifying and examining the data base for the purpose of determining the differences between shapes of various parts of the ear, (4) determining the frequency with which categories of shapes occur in the general population and also in subgroups of the population according to racial characteristics and geographic distribution; (5) determining the degree of variance between right ear and left ear characteristics of the same individual; (6) determining whether the population data base of 10,000 individuals yields sufficient data to support statistically meaningful conclusions; (7) examining the results obtained for the purpose of determining what conclusions, if any, can be drawn from a study of the data base on the degree of difference between human ears, whether they are sufficiently individual when studied in their entirely, or, if they are not "individual" and different from all others, whether there are nevertheless meaningful conclusions that can be drawn from the concurrence of a certain number of matching characteristics. 
 

What's Next

If the outcome of STEP # 4, Task (7), results in a conclusion that human ears are not sufficiently variant in their shapes and sizes to draw meaningful conclusions as to identity, then the research project is over, except for the publication of the data in the peer-reviewed literature, and presentation of the conclusions at scientific meetings so that other scientists and researchers can comment on the study's results. 

If, on the other hand, the outcome of STEP # 4, Task (7) results in a conclusion that (a) all human ears are different when studied in their entirety, or (b) even if not "unique", human ears contain a statistically significant degree of variety which may be useful in projecting the possible matching of information extracted from unknown ears and comparing them with ears of known origin, the Research Team is then to devise protocols for follow-up studies. 
 

Follow-Up Studies

Assuming the findings of the Research Team warrant further follow-up, the following further questions can thereafter be assigned to the same or a different Research Team:

Follow Up Study # 1: Is it possible to translate findings of uniqueness of full-ear photographs, or of statistically significant differences among human ears, to latent ear impressions discovered at crime scenes? 

Follow Up Study # 2: What is the proper methodology for determining whether partial or incomplete ear impressions are suitable for identification purposes? 

Follow Up Study # 3: What is the proper method for obtaining standards of known individuals’ ears for comparison with crime scene impressions? 

Follow Up Study # 4: What methodology is to be followed in making comparisons between crime scene impressions and known ear standards for the purpose of arriving at a conclusion that can be deemed to be based on reliable technical practice? 

Follow Up Study # 5: By what method are examiners to be trained in collecting both crime scene and known ear samples? How is expertise of examiners to be established, tested, and verified? 

Follow Up Study # 6: Assuming that meaningful conclusions can be drawn from the research, what is the degree of certainty with which conclusions can be expressed by examiners who compare known and unknown ear evidence? 

Length of Time of Study - Estimates to Serve As Basis for Funding Request

It is estimated that Steps 1 (Assembling the Research Team) and 2 (Convening the Research Team for a Preliminary Decision on Methodology) would take approximately five months after the initiation of a formal research project and may require three Team meetings, with individual work being done by each Research Team member between meetings.

For Step 3 (Selecting the Investigative Group and Assembling the Date of 10,000 individuals), it is estimated that at least one year will be required.

For Step 4 (Evaluation by Research Team, setting standings, doing classification, calculating statistics, and drawing conclusions), it is also estimated that an additional year will be required, with possibly four full-day or week-end meetings of the entire team and much individual effort during the intervals between meetings.

The length of time Follow-Up Studies will require is impossible to determine at this time, because these studies will of necessity depend upon the type of data assembled and interpreted in the First Research Project in the field. Assuming the research of the Project warrants further exploratory research, some of the steps in Follow-Up Studies may be able to be conducted simultaneously.

The above time sequences are purely approximate time estimates drawn from past experiences in conducting scientific inquiries from persons who have engaged in research and whose opinions were solicited. 

Send comments, suggestions, and recommendations on this proposed preliminary draft to:

Andre A. Moenssens / Andre_Moenssens@Forensic-Evidence.com
Douglas Stripp Professor of Law 
UMKC School of Law
5100 Rockhill Road
Kansas City, Missouri 64110-2499 

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