The face pool constructed from Australian newspaper images of young males, as used to test the accuracy of the facial approximation constructed by the first author (CNS). Faces are illustrated in orders corresponding with Figs. 5 and 6—top row, from left to right, indicates face numbers 1 through to 5; bottom row, from left to right indicates face numbers 6–10. 

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... approximations may not represent target individuals well enough for the target to be discriminated from a set of similar looking faces (con- trolling for type II bias), especially in sequential face arrays since the facial approximation may not look much like the target individual to begin with. Thus the inclusion of faces physically similar to the target individual may hamper identification tests. If this is the case, criteria for face selection with regard to type II bias may need to be adjusted from that used in other eyewitness identification tests (see [6]). However, this would clearly demonstrate weakness of facial approximation methods since recognition tests would be made less stringent. This aspect should be subject to further research in the future. The aims of this paper are, firstly, to provide readers with a case example of facial approximation non-success, and secondly, to specifically assess the accuracy of the facial approximation, constructed by the first author, on the Lower Light skeletal remains. The second aim is achieved by contrasting the three methods of facial approximation assessment (resemblance rating; simultaneous face array; and sequential face array), and by examining type I bias (biases not due to physical appearance of individuals) in the face array set used for testing. The face was constructed by the first author (CNS) using traditional clay three-dimensional combination methods as reported in the literature at the time of manufacture (early 1999; for review see [1]). The face was built in line with the anthropological report prepared by the second author (MH), which stated that the individual was a male between the ages of 17 and 24 years and who was about 1720 mm in height. The skull was complete except for a portion of the posterior braincase that was broken probably as a result of a blow to the head. Muscle insertions and general robustness of the skull indicated fairly well developed musculature. The skull was cast in dental plaster using a split mould technique similar to that reported by Taylor and Angel [19]. Soft tissue depths according to Helmer [20] were positioned on the skull cast and the combination approach was undertaken in the construction of the face. Prosthetic eyes were positioned centrally in the orbits, the cornea projecting to a tangent in line with the mid-supraorbital and mid-infraorbital rims (this guideline has now been demonstrated to be inaccurate [21,22]). Nose width was determined by dividing the max- imum width of the nasal aperture by 0.6 [23]. ‘‘American’’ guidelines were followed to establish nose projection using the ‘‘three times the nasal spine rule’’ ([24–27]—although updated methods are now available [28]). Mouth width was determined following the canine width rule [17,24,25], but with liberal subjective adjustment (this guideline is also now known to be inaccurate [29]). Once the muscles had been built, a sheet of clay ( $ 5 mm thick) was placed over the muscles following examples given by Prag and Neave [17]. The clay sheets were then contoured to give the final face. Ear height was a little larger than nose height, in accordance with findings by Farkas et al. [30]. Although never sighted by the practitioner, it was reported that hair found at the crime scene was fairly short and had a wavy or slightly curly appearance; hence a totally subjective estimation of hair and style was added to the facial approximation (Fig. 2). Since hair cannot be determined from the skull and because the hair reportedly collected was never presented to the first author, it is not surprising that both the hair texture and style are inaccurate on the facial approximation in comparison to the target individual. First the resemblance of the facial approximation to the target individual was established, for this is the approach traditionally taken by other practitioners in the past [14–17]. Since we wanted to make recognition as easy as possible in our other tests, we tested two photographs of the completed facial approximation, one with hair and eyebrows, and one without, to determine which appeared more similar to the target individual. Fifteen adult assessors (six males, nine females: mean age 31 years, standard deviation 10 years) judged the resemblance of both facial approximations to the target individual, giving a score from 0 to 10, and then we selected the face with the highest resemblance for use in our recognition studies. For the recognition tests a face array was constructed from newspaper images since we had access to the antemortem image of the target individual from a newspaper (Sunday Mail, 6 June 1999). Nine other distractor faces of the same sex, approximate age and approximate pose as the target individual were selected from Australian newspapers and included in the face array. All images were resampled 1 down (pixels removed), scaled and cropped in Adobe 1 Photoshop 6.0 to give images as closely comparable as possible to each other (Fig. 3). No effort was made to select individuals of similar physical appearance (in this case facial appearance) to the target as recommended in usual eyewitness tests. Thus, this face array consisted of a fairly random sample and is expected to provide a scenario favourable for correct recognitions of the facial approximation (the face array may be biased and hence some distractor faces may not be seen to be plausible alternatives to the target individual and/or the facial approximation). To determine if any type I bias was present in the face array, sequential and simultaneous presentation trials were conducted without the facial approximation. Fifteen adult assessors (11 females, 4 males: mean age 23 years, standard deviation 12 years) who did not recognize, either personally or as having been seen in the media, any of the faces in the face array were asked to determine, without the facial approximation, who the murder victim (target individual) was in the face array. Assessors had no information apart from the photographs themselves to base this decision on. Assessors first participated in the sequential face array presentation and then the simultaneous line-up. In the sequential face array assessors where shown one face image at a time in a random order. Assessors were forced to decide for each face ‘‘yes’’ or ‘‘no’’ if the face was that of the murder victim. Assessors were aware that if they made an identification of ‘‘yes’’ the trial was completed (they would not see the other faces in the sequence during this test) and if they answered ‘‘no’’ that they would not be able to change their mind to this face at a later point in the trial. The investigator (CNS) held more cards than those included in the face array test so that assessors could not anticipate the end of the sequence. In the sequential trial cards were held about 1 m in front of the assessor and at arm’s length from the investigator at 90% to his line of sight so investigator cues, if there were any, were not obvious to assessors (who were hopefully concentrating on the cards and hence not attending to any cues, particularly facial ones, if expressed by the investigator). After assessors had made an identification, or if they proceeded through all the faces in the sequence without making an identification, all the faces in the array were presented simultaneously, but in a random order, to the assessor for him/her to change their identification decision from the sequential trial if they so wished. Twenty new assessors (14 females, 6 males: mean age 20 years, standard deviation 4 years) who did not recognize, either personally or as having been seen in the media, any of the faces in the face array, were recruited for the main project: to attempt to correctly identify who the target individual was from the facial approximation. Identical procedures were followed as indicated above for face pool testing without the facial approximation, except of course that this time the assessors had access to a facial approximation. Although assessors had the option of not choosing any face in the simultaneous line-up, a chance rate of 10% was used as it was found that almost all assessors selected a face (see Section 3), and hence appeared biased in this respect (according to chance one would expect a 50% response of ‘‘not there’’, instead it seemed all assessors were choosing a face and hence each face in the array had a 10% chance of being selected). Responses were recorded categorically as correct (target face identification) or incorrect (distractor identification or ‘‘no identification’’ response) for statistical analysis. Observed data were compared to expected frequen- 1 cies by Fisher’s Exact tests in the JMP 4.0 statistical package. As we were only interested in responses larger than chance (and because chance rates were so small that lesser differences would be difficult to detect) confidence intervals for one tailed tests were used. Assessor’s resemblance ratings of both facial approximations were in accordance with previous indications from other individuals, including other forensic facial approximation experts, that resemblance was high. It is worth noting that Betty Pat Gatliff, a high profile forensic artist and facial approximation practitioner, indicated to the first author in 2000 that the face appeared similar enough that she would have expected a positive result had it been advertised. Both facial approximations received high, but similar, resemblance rating results (around 7 out of 10), although the facial approximation without hair tended to be rated higher than the facial approximation with hair (Fig. 4). Data distributions for the no hair facial approximation displayed slightly more left skew than those for the facial approximation with hair (Fig. 4). Hence in recognition tests reported here we used the facial approximation without hair as this is expected to favour positive recognition responses according to traditional ...