An evaluation of US systems for facial composite production

Witness and victims of serious crime are normally requested to construct a facial composite of a suspect’s face. While modern systems for constructing composites have been evaluated extensively in the UK, this is not the case in the US. In the current work, two popular computerized systems in the US, FACES and Identikit 2000, were evaluated against a ‘reference’ system, PRO-fit, where performance is established. In Experiment 1, witnesses constructed a composite with both PRO-fit and FACES using a realistic procedure. The resulting composites were very poorly named, but the PRO-fit emerged best in ‘cued’ naming and two supplementary measures: composite sorting and likeness ratings. In Experiment 2, PRO-fit was compared with Identikit 2000, a sketch-like feature system. Spontaneous naming was again very poor, but both cued naming and sorting suggested that the systems were similar. The results support previous findings that modern systems do not produce identifiable composites

Witness Interviews: Does recall of relational information improve identifiability of a facial composite?

Facial composites are used by Police to generate lines of enquiry; unfortunately composites made by traditional ‘feature’ systems are not often accurately named. One reason could be that these systems tend to rely on descriptions of the criminal’s facial features, when it has been shown that relationships and distances between facial features—the relational information—is of importance for face recognition. Here, we present two experiments to investigate the usefulness of probing for relational information within witness interviews. Participant-witnesses underwent a typical cognitive interview (CI), an interview in which featural information was probed for before relational information (FR), or an interview in which probing for relational information preceded probing for featural detail (RF). Composites constructed of familiar targets with no delay were recognised better in the former two interviews than the latter, suggesting that relational information interferes with subsequent recall of featural information. However, after a 24 hour delay composites constructed of unfamiliar targets did not differ significantly for naming rates by interview type. This indicates no naming benefit for recalling relational information. However, RF composites were rated as significantly better likenesses to target images after a 24-hour delay, and so future work could explore this further to assess what aspect of the image is improved by recall of relational information

The benefit of context for facial composite construction.

Purpose - The aim of this study was to investigate whether the presence of a whole-face context during facial composite production facilitates construction of facial composite images.Design/Methodology - In Experiment 1, constructors viewed a celebrity face and then developed a facial composite using PRO-fit in one of two conditions: either the full-face was visible while facial features were selected, or only the feature currently being selected was visible. The composites were named by different participants. We then replicated the study using a more forensically-valid procedure: In Experiment 2 non-football fans viewed an image of a premiership footballer and 24 hours later constructed a composite of the face with a trained software operator. The resulting composites were named by football fans.Findings - In both studies we found that presence of the facial context promoted more identifiable facial composite images.Research limitations/implications – Though this study uses current software in an unconventional way, this was necessary to avoid error arising from between-system differences.Practical implications - Results confirm that composite software should have the whole-face context visible to witnesses throughout construction. Though some software systems do this, there remain others that present features in isolation and these findings show that these systems are unlikely to be optimal. Originality/value - This is the first study to demonstrate the importance of a full-face context for the construction of facial composite images. Results are valuable to police forces and developers of composite software

Face-space: A unifying concept in face recognition research

The concept of a multidimensional psychological space, in which faces can be represented according to their perceived properties, is fundamental to the modern theorist in face processing. Yet the idea was not clearly expressed until 1991. The background that led to the development of face-space is explained, and its continuing influence on theories of face processing is discussed. Research that has explored the properties of the face-space and sought to understand caricature, including facial adaptation paradigms, is reviewed. Face-space as a theoretical framework for understanding the effect of ethnicity and the development of face recognition is evaluated. Finally, two applications of face-space in the forensic setting are discussed. From initially being presented as a model to explain distinctiveness, inversion, and the effect of ethnicity, face-space has become a central pillar in many aspects of face processing. It is currently being developed to help us understand adaptation effects with faces. While being in principle a simple concept, face-space has shaped, and continues to shape, our understanding of face perception

Do intoxicated witnesses produce poor facial composite images?

The effect of alcohol intoxication on witness memory and performance has been the subject of research for some time, however, whether intoxication affects facial composite construction has not been investigated. Intoxication was predicted to adversely affect facial composite construction. Thirty-two participants were allocated to one of four beverage conditions consisting of factorial combinations of alcohol or placebo at face encoding, and later construction. Participants viewed a video of a target person and constructed a composite of this target the following day. The resulting images were presented as a full face composite, or a part face consisting of either internal or external facial features to a second sample of participants who provided likeness ratings as a measure of facial composite quality. Intoxication at face encoding had a detrimental impact on the quality of facial composites produced the following day, suggesting that alcohol impaired the encoding of the target faces. The common finding that external compared to internal features are more accurately represented was demonstrated, even following alcohol at encoding. This finding was moderated by alcohol and target face gender such that alcohol at face encoding resulted in reduced likeness of external features for male composite faces only. Moderate alcohol intoxication impairs the quality of facial composites, adding to existing literature demonstrating little effect of alcohol on line-up studies. The impact of intoxication on face perception mechanisms, and the apparent narrowing of processing to external face areas such as hair, is discussed in the context of alcohol myopia theory

Familiarity effects in the construction of facial composite images using modern software systems.

We investigate the effect of target familiarity on the construction of facial composites, as used by law-enforcement to locate criminal suspects. Two popular software construction methods were investigated. Participants were shown a target face that was either familiar or unfamiliar to them and constructed a composite of it from memory using a typical ‘feature’ system, involving selection of individual facial-features, or one of the newer ‘holistic’ types, involving repeated selection and breeding from arrays of whole faces. The study found that composites constructed of a familiar face were named more successfully than composites of an unfamiliar face; also, naming of composites of internal and external features were equivalent for unfamiliar targets, but internal features were better named than external features for familiar targets. These findings applied to both systems, although benefit emerged for the holistic type due to more accurate construction of internal features and evidence for a whole-face advantage

Constructing identifiable composite faces: The importance of cognitive alignment of interview and construction procedure.

We investigated the impact of congruency between the witness interview and method used to construct a composite face. Experiment 1, using a typical feature-by-feature composite method, revealed that aligning cognitive processes during interview and face construction enhanced the effectiveness of composites compared with composites produced following unaligned (incongruent) procedures. Experiment 2 revealed that incorporating character judgements in the witness interview substantially enhanced identification of feature-based composites when constructing the central (internal) features first, suggesting that such judgements focus attention on this region of the face. Experiment 3 explored alignment of processes using an approach based on an evolutionary algorithm, a method requiring witnesses to create a composite by selecting from arrays based on the eye-region. A combination of character judgements, first for the whole face and then for the eye region, led to best-identified composites. Overall, results indicate that more effective composites are produced when both interview and construction procedures are aligned cognitively. Results are discussed with relevance to the theory of transfer-appropriate processing (Morris, Bransford, & Franks, 1977)

The impact of external facial features on the construction of facial composites

Witnesses may construct a composite face of a perpetrator using a computerised interface. Police practitioners guide witnesses through this unusual process, the goal being to produce an identifiable image. However, any changes a perpetrator makes to their external facial-features may interfere with this process. In Experiment 1, participants constructed a composite using a holistic interface one day after target encoding. Target faces were unaltered, or had altered external-features: (i) changed hair, (ii) external-features removed or (iii) naturally-concealed external-features (hair, ears, face-shape occluded by a hooded top). These manipulations produced composites with more error-prone internal-features: participants’ familiar with a target’s unaltered appearance less often provided a correct name. Experiment 2 applied external-feature alterations to composites of unaltered targets; although whole-face composites contained less error-prone internal-features, identification was impaired. Experiment 3 replicated negative effects of changing target hair on construction and tested a practical solution: selectively concealing hair and eyes improved identification

Recovering faces from memory: the distracting influence of external facial features.

Recognition memory for unfamiliar faces is facilitated when contextual cues (e.g. head pose, background environment, hair and clothing) are consistent between study and test. By contrast, inconsistencies in external features, especially hair, promote errors in unfamiliar face-matching tasks. For the construction of facial composites, as carried out by witnesses and victims of crime, the role of external features (hair, ears and neck) is less clear, although research does suggest their involvement. Here, over three experiments, we investigate the impact of external features for recovering facial memories using a modern, recognition-based composite system, EvoFIT. Participant-constructors inspected an unfamiliar target face and, one day later, repeatedly selected items from arrays of whole faces, with ‘breeding’, to ‘evolve’ a composite with EvoFIT; further participants (evaluators) named the resulting composites. In Experiment 1, the important internal-features (eyes, brows, nose and mouth) were constructed more identifiably when the visual presence of external features was decreased by Gaussian blur during construction: higher blur yielded more identifiable internal-features. In Experiment 2, increasing the visible extent of external features (to match the target’s) in the presented face-arrays also improved internal-features quality, although less so than when external features were masked throughout construction. Experiment 3 demonstrated that masking external-features promoted substantially more identifiable images than using the previous method of blurring external-features. Overall, the research indicates that external features are a distractive rather than a beneficial cue for face construction; the results also provide a much better method to construct composites, one that should dramatically increase identification of offenders

The impact of weapons and unusual objects on the construction of facial composites

The presence of a weapon in the perpetration of a crime can impede an observer’s ability to describe and/or recognise the person responsible. In the current experiment, we explore whether weapons when present at encoding of a target identity interfere with the construction of a facial composite. Participants encoded an unfamiliar target face seen either on its own or paired with a knife. Encoding duration (10 or 30 s) was also manipulated. The following day, participants recalled the face and constructed a composite of it using a holistic system (EvoFIT). Correct naming of the participants’ composites was found to reduce reliably when target faces were paired with the weapon at 10 s but not at 30 s. These data suggest that the presence of a weapon reduces the effectiveness of facial composites following a short encoding duration. Implications for theory and police practice are discussed