Developmental improvement and age-related decline in unfamiliar face matching

Age-related changes have been documented widely in studies of face recognition and eyewitness identification. However, it is not clear whether these changes arise from general developmental differences in memory or occur specifically during the perceptual processing of faces. We report two experiments to track such perceptual changes using a 1-in-10 (Experiment 1) and 1-in-1 (Experiment 2) matching task for unfamiliar faces. Both experiments showed improvements in face matching during childhood and adult-like accuracy levels by adolescence. In addition, face-matching performance declined in adults of the age of 65. These findings indicate that developmental improvements and aging-related differences in face processing arise from changes in the perceptual encoding of faces. A clear face inversion effect was also present in all age groups. This indicates that those age-related changes in face matching reflect a quantitative effect, whereby typical face processes are engaged but do not operate at the best-possible level. These data suggest that part of the problem of eyewitness identification in children and elderly persons might reflect impairments in the perceptual processing of unfamiliar faces

Perceived ability and actual recognition accuracy for unfamiliar and famous faces

In forensic person recognition tasks, mistakes in the identification of unfamiliar faces occur frequently. This study explored whether these errors might arise because observers are poor at judging their ability to recognize unfamiliar faces, and also whether they might conflate the recognition of familiar and unfamiliar faces. Across two experiments, we found that observers could predict their ability to recognize famous but not unfamiliar faces. Moreover, observers seemed to partially conflate these abilities by adjusting ability judgements for famous faces after a test of unfamiliar face recognition (Experiment 1) and vice versa (Experiment 2). These findings suggest that observers have limited insight into their ability to identify unfamiliar faces. These experiments also show that judgements of recognition abilities are malleable and can generalize across different face categories

The effect of image pixelation on unfamiliar face matching

Low-resolution, pixelated images from CCTV can be used to compare the perpetrators of crime with high-resolution photographs of potential suspects. The current study investigated the accuracy of person identification under these conditions, by comparing high-resolution and pixelated photographs of unfamiliar faces in a series of matching tasks. Performance decreased gradually with different levels of pixelation and was close to chance with a horizontal image resolution of only 8 pixel bands per face (Experiment 1). Matching accuracy could be improved by reducing the size of pixelated faces (Experiment 2) or by varying the size of the to-be-compared-with high-resolution face image (Experiment 3). In addition, pixelation produced effects that appear to be separable from other factors that might affect matching performance, such as changes in face view (Experiment 4). These findings reaffirm that criminal identifications from CCTV must be treated with caution and provide some basic estimates for identification accuracy with different pixelation levels. This study also highlights potential methods for improving performance in this task

The role of attention in face processing

Selective attention is widely regarded as a crucial component of human perception. In the visual domain, attentional mechanisms have been implicated in stimulus encoding, implicit recognition, conscious perception and goal-directed behaviour. To date, however, the role of attention in face processing has been largely overlooked. This is remarkable given the social and biological importance of faces, and the wealth of psychological research that has focused on faces as stimuli. Moreover, if we are to better understand how the human brain processes faces, then this would also require an insight into the interaction between attention and face processing. The experiments in this thesis addressed the relation of attention and face processing directly by assessing the consequences of various attentional manipulations in response-competition and repetition priming tasks. The first line of enquiry examined observers’ ability to attend selectively to facial expression and identity, and whether attention is required for the integration of these types of information into a multi-dimensional face percept. Subsequent experiments examined capacity limits in face processing and attention biases to faces and nonface comparisons. The main findings indicated that face processing is capacity limited, such that only a single face can be processed at a time, and that faces are particularly efficient at retaining and engaging visual attention in comparison to nonface objects. However, while face processing limits appear to proceed independent of a general capacity, attention biases to faces may reflect processing stages that are shared with other stimuli. These findings are discussed in relation to existing research on faces and attention

Feature instructions improve face-matching accuracy

Identity comparisons of photographs of unfamiliar faces are prone to error but important for applied settings, such as person identification at passport control. Finding techniques to improve face-matching accuracy is therefore an important contemporary research topic. This study investigated whether matching accuracy can be improved by instruction to attend to specific facial features. Experiment 1 showed that instruction to attend to the eyebrows enhanced matching accuracy for optimized same-day same-race face pairs but not for other-race faces. By contrast, accuracy was unaffected by instruction to attend to the eyes, and declined with instruction to attend to ears. Experiment 2 replicated the eyebrow-instruction improvement with a different set of same-race faces, comprising both optimized sameday and more challenging different-day face pairs. These findings suggest that instruction to attend to specific features can enhance face-matching accuracy, but feature selection is crucial and generalization across face sets may be limited. - 2018 Megreya, Bindemann. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Scopu

The shape of the face template: Geometric distortions of faces and their detection in natural scenes

Human face detection might be driven by skin-coloured face-shaped templates. To explore this idea, this study compared the detection of faces for which the natural height-to-width ratios were preserved with distorted faces that were stretched vertically or horizontally. The impact of stretching on detection performance was not obvious when faces were equated to their unstretched counterparts in terms of their height or width dimension (Experiment 1). However, stretching impaired detection when the original and distorted faces were matched for their surface area (Experiment 2), and this was found with both vertically and horizontally stretched faces (Experiment 3). This effect was evident in accuracy, response times, and also observers’ eye movements to faces. These findings demonstrate that height-to-width ratios are an important component of the cognitive template for face detection. The results also highlight important differences between face detection and face recognition

Understanding face identification through within-person variability in appearance: Introduction to a virtual special issue

In the effort to determine the cognitive processes underlying the identification of faces, the dissimilarities between images of different people have long been studied. In contrast, the inherent variability between different images of the same face has either been treated as a nuisance variable that should be eliminated from psychological experiments or it has not been considered at all. Over the past decade, research efforts have increased substantially to demonstrate that this within-person variation is meaningful and can give insight into various processes of face identification, such as identity matching, face learning, and familiar face recognition. In this virtual special issue of the Quarterly Journal of Experimental Psychology, we explain the importance of within-person variability for face identification and bring together recent relevant articles published in the journal

Human-computer interaction in face matching

Automatic facial recognition is becoming increasingly ubiquitous in security contexts such as passport control. Currently, Automated Border Crossing (ABC) systems in the United Kingdom (UK) and the European Union (EU) require supervision from a human operator who validates correct identity judgements and overrules incorrect decisions. As the accuracy of this human-computer interaction is unknown, this research investigated how human validation is impacted by a priori face-matching decisions such as those made by automated face recognition software. Observers matched pairs of faces that were already labelled onscreen as depicting the same identity or two different identities. The majority of these labels provided information that was consistent with the stimuli presented, but some were also inconsistent or provided ‘unresolved’ information. Across three experiments, accuracy consistently deteriorated on trials that were inconsistently labelled, indicating that observers’ face-matching decisions are biased by external information such as that provided by ABCs