Experimental Design 1 Experiment 1 (Pilot)

Participants were asked to establish sex, ancestry, and age at death estimations (the most common attributes to provide a biological profile) on two different occasions on a set of skulls and os coxa, based on visual assessments. This approach was undertaken to firstly establish a baseline control. This was done in order to assess what decisions would be made without any contextual information. Secondly to provide contextual information (prior to participants assessments) to assess whether the interpretation of the skeletal remains made by the participants would be differ and change when given ‘contradicting’ context. The experiment took place over a two-month period with a 3-week interval in-between each phase of the study (see Table 3.1). The timeframe of the experiment was based on the availability of the participants as well as time constrains.

3.2.1.2. Experiment 2 (Follow up study)

Based on the limitations of the pilot study (Experiment 1), Experiment 2 was designed as a follow up and control study. This was done in order to a) address the constraints observed in Experiment 1 (such as the lack of a second control-reliability round) in order to cap any variables that could have affected the results, and b) to replicate the study in order to increase the number of participants. Participants in Experiment 2 were also asked to establish sex, ancestry and age at death estimations on three different occasions on the same a set of skulls and os coxa used in Experimental 1, based on visual assessments. Similar to Experimental 1, this approach sought to firstly set a baseline control (in order to assess with a control condition what decisions would be made without any contextual information,) secondly, to provide contextual information (to assess whether the decisions of participants would be different and change when given contradicting context), and thirdly, to again provide participants with no contextual information (for a second time) as a further control to test for reliability and exclude any ‘noise ‘ that might have affected the results from Experiment 1. In addition, participants in Experiment 2 were also asked to assess their confidence level for each assessment on a numerical scale from 1-100. This was added in the experimental procedure in order to understand the decision-making process and the confidence in the decision-making

for the participants. The experiment took place over a 3-month period with a 3 -week interval in-between each phase of the study (see Table 3.1).

Table 3.1 Time table of the research design

Experiment phase (Experiment 1)

Week Circumstances of the analysis Number of participants

Analysis 1 (baseline –

control) 1

No contextual information

18 Analysis 2 (context) 4 Contradictory contextual information 18

Experiment phase (Experiment 2)

Analysis 1 (baseline –

control) 1

No contextual information 22 Analysis 2 (context) ₄ Contradictory contextual information

22 Analysis 3 (reliability- control 7 No contextual information 22 3.2.2. Materials

Three skulls and two os coxa were selected from the skeletal collection curated by the UCL Institute of Archaeology, with the material originating from archaeological excavations. The selection of the skeletal remains was identical for both Experiment 1 and 2. The selection was made by undertaking a pilot test run to assess the characteristics of each set of remains to determine the degree of ambiguity, thereby identifying remains where the morphological features present on the skulls and the os coxa were of a complex nature, showing mixed traits of female, or male characteristics. Furthermore, no extreme trait distinction regarding ancestry was included as well as ambiguity in age at death, due to the wide age ranges generally assessed in forensic anthropology. This was of specific importance in this study

because cognitive influences have been shown to be more predominant in ambiguous and complex cases (Kassin et al. 2013).

The skulls were intact and in a good condition, making it possible to conduct a visual assessment on sex and ancestry. Equally, the two os coxa were both partly intact with the Ilium, Pubic and Ischium bones presented for visual analysis on sex and age at death estimations (see Fig. 3.1).

Figure 3.1 Showing the three skulls and two os coxa skeletal used for this study 3.2.3. The contextual information

The contextual information was provided separately for each component of the skeletal remains, and was presented next to each skeletal element in the form of a short report. The information included elements of grave context descriptions as well as information taken from the osteological report of the site, as exemplified in the extract below.

“This individual was excavated from St Brides Crypt, known to represent affluent individuals, with the majority of the burials being of Caucasian descent. According to grave context descriptions, a whalebone (commonly used for corset stays) was found in addition to the skeletal remains”

The nature of the contextual information used in this study was based upon archaeological and osteological reports and archives, grave artefacts, and site descriptions. This was done to provide the participants with realistic and credible contexts for each skeletal element. Consequently, information regarding a forensic setting was not included in this study and equally, each context for each skeletal element differed but all indicative of a certain sex, ancestry or age at death (see Appendix B for full list over the contextual information for each skeletal element). The contextual information given to the participants contradicted the majority of the previous estimations of the participants. For example, if a participant estimated the skeletal remains to be male in previous decisions, context was given to indicate a female and vice versa. A similar approach was taken for ancestry and age at death estimations.

3.2.4. Participants