
Robin Stewart Samuel KramerUniversity of Lincoln · School of Psychology
Robin Stewart Samuel Kramer
PhD
About
122
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Introduction
I am currently interested in face perception and recognition. I use experimental methods, as well as computational modelling techniques, in order to better understand how we perceive, learn, recognise, and represent faces.
Skills and Expertise
Publications
Publications (122)
For unfamiliar faces, deciding whether two photographs depict the same person or not can be difficult. One way to substantially improve accuracy is to defer to the ‘wisdom of crowds’ by aggregating responses across multiple individuals. However, there are several methods available for doing this. Here, we investigated performance in three tests of...
Objectives
Parents infrequently recognize childhood overweight/obesity and healthcare professionals (HCPs) also struggle to visually identify it, potentially limiting the offer and uptake of weight management support. This study examined perceptual and attitudinal/cognitive determinants of child weight judgements amongst parents and HCPs to identif...
ChatGPT's large language model, GPT-4V, has been trained on vast numbers of image-text pairs and is therefore capable of processing visual input. This model operates very differently from current state-of-the-art neural networks designed specifically for face perception and so I chose to investigate whether ChatGPT could also be applied to this dom...
Background/Objectives: It is vital to identify children whose weight status means that they may benefit from medical or behavioural support, but adult visual judgements of child weight status are inaccurate, and children are seldom routinely weighed and measured. Consequently, there is a need for validated visual tools for use in training, communic...
First impressions based on facial appearance affect our behaviour towards others. Since the same face will appear different across images, over time, and so on, our impressions may not be equally weighted across exposures but are instead disproportionately influenced by earlier or later instances. Here, we followed up on previous work which identif...
Artificial intelligence can now synthesise face images which people cannot distinguish from real faces. Here, we investigated the wisdom of the (outer) crowd (averaging individuals' responses to the same trial) and inner crowd (averaging the same individual's responses to the same trial after completing the test twice) as routes to increased perfor...
There has been an assumption in the literature that the three concepts of ideal body shape (personal ideal,
cultural ideal, and the most attractive body shape) are effectively the same percept. To test this presumption, 554
participants completed either a between- or within-subjects condition using a matrix of 32 bodies varying in two
dimensions: m...
Perceiving facial attractiveness is an important behaviour across psychological science due to these judgments having real-world consequences. However, there is little consensus on the measurement of this behaviour, and practices differ widely. Research typically asks participants to provide ratings of attractiveness across a multitude of different...
Deciding whether two face photographs depict the same person or not can be a challenging task, and there are substantial individual differences in face matching ability. Far less is known about differences in metacognitive ability; that is, how well people can estimate the quality of their own face matching judgements. The purpose of this Registere...
Within the domain of face processing, researchers have been interested in quantifying the relationship between objective (i.e., performance on laboratory tests of recognition and matching) and subjective measures of ability (typically, self-report questionnaires). Put simply, do people show high levels of metacognitive insight into their own abilit...
Facial first impressions influence jurors in both laboratory experiments and real courtrooms. Often, more attractive defendants are perceived as less guilty and receive more lenient sentences. However, the type of crime under consideration, as well as the ecological validity of the stimuli presented, may determine the nature of this bias. Here, ext...
Identification often involves determining whether two face photographs or voice samples originated from the same person. Here, we investigated the wisdom of the (outer) crowd (averaging two individuals' responses to the same trial) and inner crowd (averaging the same individual's responses to the same trial after completing the test twice) as route...
It is becoming increasingly common for face morphs (weighted combinations of two people’s photographs) to be submitted for inclusion in an official document, such as a passport. These images may sufficiently resemble both individuals that they can be used by either person in a ‘fraudulently obtained genuine’ document. Problematically, people are po...
Introduction
To determine men's body ideals and the factors that influence these choices, this study used a matrix of computer generated (CG) male bodies (based on an analysis of 3D scanned real bodies) which independently varied in fat and muscle content.
Methods
Two hundred and fifty-eight male participants completed a range of psychometric meas...
Background
Although researchers have begun to consider metacognitive insight during face matching, little is known about the underlying mechanism. Here, I investigated whether objective ability, as well as self-assessed ability, were able to predict metacognitive performance, that is, the ability to differentiate correct and incorrect responses in...
It is unclear whether witness mental illness and special measures used with witnesses in court impacts juror decision-making. Participants (N = 204) from the general public and student population completed a measure assessing attitudes towards mental illness before reading a mock trial vignette where witness mental illness (depression, schizophreni...
We used attractiveness judgements as a proxy to visualize the ideal female and male body for male and female participants and investigated how individual differences in the internalization of cultural ideals influence these representations. In the first of two studies, male and female participants judged the attractiveness of 242 male and female co...
Facial first impressions are known to influence how we behave towards others. As a result of the COVID-19 pandemic, we often view incomplete faces due to the commonplace wearing of face masks. Previous research has shown that perceptions of attractiveness are often increased due to these coverings, with initial evidence suggesting that this may be...
Our Meet the Supervisors section is aimed at connecting postgraduate psychology students with potential supervisors and any corresponding opportunities for PhD, RA or postdoctoral research projects they may have in the future. We want to showcase some of the amazing supervisors and research positions out there. We also aim to humanise the PhD/RA/po...
A wealth of studies have shown that humans are remarkably poor at determining whether two face images show the same person or not (face matching). Given the prevalence of photo-ID, and the fact that people employed to check photo-ID are typically unfamiliar with the person pictured, there is a need to improve unfamiliar face matching accuracy. One...
When you describe yourself and the people you know, the words you use might be different for each person. Maybe your sister is creative, and your brother is friendly. You could even describe your dog as playful and your neighbor’s cat as nervous! The descriptions are different because each of you has a different personality—that is, you differ from...
Kruger and Dunning (1999) described a metacognitive bias in which insight into performance is linked to competence: poorer performers are less aware of their mistakes than better performers. Competence-based insight has been argued to apply generally across task domains, including a recent report investigating social cognition using a variety of fa...
When items are presented sequentially, the evaluation of the current item is biased by both the previous item’s value (perceptual bias) and the previous response given (response bias). While these biases have been identified in judgements of facial attractiveness, it is unclear as to whether they produce assimilation and/or contrast effects. Here,...
Recently in this journal, Bilgin and Wolke (2020) published a paper which showed no association between leaving infants to ‘cry it out’ and infant-mother attachment. In our commentary (Davis & Kramer, 2021), we argued that the study was underpowered and, as such, could not be considered a conclusive demonstration that ‘cry it out’ had no adverse ef...
Automatic facial recognition technology (AFR) is increasingly used in criminal justice systems around the world, yet to date there has not been an international survey of public attitudes toward its use. In Study 1, we ran focus groups in the UK, Australia and China (countries at different stages of adopting AFR) and in Study 2 we collected data fr...
When dating, women seek men slightly older than themselves while men typically prefer younger women. Such patterns reflect differences in parental investment and age-related fertility, which are both concerned with maximizing reproductive outcomes. Using large samples of online daters, we considered whether having or wanting children was associated...
Objective:
The importance of breastfeeding for both maternal and infant health is well established. However, it remains the case that only a small percentage of infants are breastfed after the first six months of life. Maternal negative breastfeeding attitudes are associated with a reduced likelihood of breastfeeding an infant, but they are a mall...
Background
Although face recognition is now well studied, few researchers have considered the nature of forgetting over longer time periods. Here, I investigated how newly learned faces were recognised over the course of one week. In addition, I considered whether self-reported face recognition ability, as well as Big Five personality dimensions, w...
Attachment styles in individuals with autism are not well understood, and research into the topic is limited to date. Authors regularly utilise standardised measures to classify attachment in adulthood, and this is the case for research with neurotypical and autistic populations. Here, we argue that there may be fundamental problems with using such...
Previous research has shown that exposure to within-person variability facilitates face learning. A different body of work has examined potential benefits of providing multiple images in face matching tasks. Viewers are asked to judge whether a target face matches a single face image (as when checking photo-ID) or multiple face images of the same p...
Although typical journal publications take the form of research articles, there are other avenues to publishing that might help with building up your CV or immersing yourself in research. I recently wrote a critical commentary after coming across an article that I had some objections towards. The process was both interesting and educational, and co...
Psychological concerns are frequently indexed by psychometric questionnaires but the mental representations that they seek to quantify are difficult to visualise. We used a set of questionnaires designed to measure men’s concept of their bodies including: the Drive for Muscularity Scale (DMS; McCreary & Sasse, 2000), the Perceived Sociocultural Pre...
Existing models of facial first impressions indicate between two and four factors that underpin all social trait judgements. Here, we submitted several large databases of these first impression ratings to unsupervised learning algorithms with the aim of clustering together faces, rather than traits, to examine the ways in which impressions may be g...
In their recent paper published in JCPP, Bilgin and Wolke (2020a) argue that leaving an infant to ‘cry it out’, rather than responding to the child’s cries, had no adverse effects on mother–infant attachment at 18 months. This finding opposes evidence across a wide range of scientific fields. Here, we outline several concerns with the article and a...
Deciding whether two different face photographs or voice samples are from the same person represent fundamental challenges within applied settings. To date, most research has focussed on average performance in these tests, failing to consider individual differences and within‐person consistency in responses. Here, participants completed the same fa...
Accurate self-assessment of body shape and size plays a key role in the prevention, diagnosis, and treatment of both obesity and eating disorders like anorexia nervosa. These chronic conditions cause significant health problems, reduced quality of life, and represent a major problem for health services worldwide. Variation in body shape depends on...
When evaluating items in a sequence, the current judgment is influenced by the previous item and decision. These sequential biases take the form of assimilation (shifting toward the previous item/decision) or contrast (shifting away). Previous research investigating facial attractiveness evaluations provides mixed results while using analytical tec...
Face familiarity produces advantages for both memory and matching. By developing an internal representation through repeated experience, viewers extract identity-specific information that aids subsequent recognition. However, researchers have recently argued that this process may also result in a familiarity disadvantage, whereby specific instances...
Research into the effects of mindfulness meditation on behavioral outcomes has received much interest in recent years, with benefits for both short-term memory and working memory identified. However, little research has considered the potential effects of brief mindfulness meditation interventions or the nature of any benefits for visual short-term...
Hyper-realistic face masks have been used as disguises in at least one border crossing and in numerous criminal cases. Experimental tests using these masks have shown that viewers accept them as real faces under a range of conditions. Here, we tested mask detection in a live identity verification task. Fifty-four visitors at the London Science Muse...
When interacting with other humans, facial expressions provide valuable information for approach or avoid decisions. Here, we consider facial attractiveness as another important dimension upon which approach-avoidance behaviours may be based. In Experiments 1-3, we measured participants' responses to attractive and unattractive women's faces in an...
Eyewitness descriptions provide critical information for the police and other agencies to use during investigations. While researchers have typically considered the impact of memory, little consideration has been given to the utility of facial descriptions themselves, without the additional memory demands. In Experiment 1, participants described fa...
Background:
In recent years, fraudsters have begun to use readily accessible digital manipulation techniques in order to carry out face morphing attacks. By submitting a morph image (a 50/50 average of two people's faces) for inclusion in an official document such as a passport, it might be possible that both people sufficiently resemble the morph...
Investigations of face identification have typically focussed on matching faces to photographic IDs. Few researchers have considered the task of searching for a face in a crowd. In Experiment 1, we created the Chokepoint Search Test to simulate real‐time search for a target. Performance on this test was poor (39% accuracy) and showed moderate assoc...
Our first impressions of others, whether accurate or unfounded, have real-world consequences in terms of how we judge and treat those people. Previous research has suggested that criminal sentencing is influenced by the perceived facial trustworthiness of defendants in murder trials. In real cases, those who appeared less trustworthy were more like...
Recently, there has been a shift towards the use of 3D scanning technology in body size perception research. Based on limitations of previous methodologies there is a need to develop and validate female body stimuli that are high-resolution, photo-realistic and biometrically accurate, and modern technology makes this possible. The aim of this proje...
A paradoxical finding from recent studies of face perception is that observers are error-prone and inconsistent when judging the identity of unfamiliar faces, but nevertheless reasonably consistent when judging traits. Our aim is to understand this difference. Using everyday ambient images of faces, we show that visual image statistics can predict...
Models of social evaluation aim to capture the information people use to form first impressions of unfamiliar others. However, little is currently known about the relationship between perceived traits across gender. In Study 1, we asked viewers to provide ratings of key social dimensions (dominance, trustworthiness etc.) for multiple images of 40 u...
We know from previous research that unfamiliar face matching (determining whether two simultaneously presented images show the same person or not) is very error‐prone. A small number of studies in laboratory settings have shown that the use of multiple images or a face average, rather than a single image, can improve face matching performance. Here...
Matching two different images of an unfamiliar face is difficult, although we rely on this process every day when proving our identity. Although previous work with laboratory photosets has shown that performance is error-prone, few studies have focussed on how accurately people carry out this matching task using photographs taken from official form...
A growing body of research has investigated how we associate colours and social traits. Specifically, studies have
explored the links between red and perceptions of qualities like attractiveness and anger. Although less is known about
other colours, the prevailing framework suggests that the specific context plays a significant role in determining...
Researchers have long been interested in how social evaluations are made based upon first impressions of faces. It is also important to consider the level of agreement we see in such evaluations across raters and what this may tell us. Typically, high levels of inter-rater agreement for facial judgements are reported, but the measures used may be m...
Within-participant reliability and estimates of shared and private taste.
(DOCX)
Participants’ ratings for all traits.
(XLSX)
Different measures that are often reported in the context of scale or rater consistency.
(DOCX)
Low‐quality images are problematic for face identification, for example, when the police identify faces from CCTV images. Here, we test whether face averages, comprising multiple poor‐quality images, can improve both human and computer recognition. We created averages from multiple pixelated or nonpixelated images and compared accuracy using these...
Background Infants and children travel using passports that are typically valid for five years (e.g. Canada, United Kingdom, United States and Australia). These individuals may also need to be identified using images taken from videos and other sources in forensic situations including child exploitation cases. However, few researchers have examined...
Raw data for all experiments.
Previous research has shown that displaying the color red can increase attractiveness. As a result, women display red more often when expecting to meet more attractive men in a laboratory context. Here, we carried out a field study by analyzing 546 daters from the “First Dates” television series. Each participant was filmed in a pre-date interview...
Research has systematically examined how laboratory participants and real-world practitioners decide whether two face photographs show the same person or not using frontal images. In contrast, research has not examined face matching using profile images. In Experiment 1, we ask whether matching unfamiliar faces is easier with frontal compared with...
It has been known for many years that identifying familiar faces is much easier than identifying unfamiliar faces, and that this familiar face advantage persists across a range of tasks. However, attempts to understand face familiarity have mostly used a binary contrast between 'familiar' and 'unfamiliar' faces, with no attempt to incorporate the v...
The poster explores the effects of gender and familiarity on first impressions from faces. Main findings include a negative relationship between ratings of trustworthiness and dominance for female, but not male identities as well as more consistent ratings attributed to different images of the same familiar, compared to unfamiliar, identity.
Photographs of people are commonly said to be 'good likenesses' or 'poor likenesses', and this is a concept that we readily understand. Despite this, there has been no systematic investigation of what makes an image a good likeness, or of which cognitive processes are involved in making such a judgement. In three experiments, we investigate likenes...
Researchers have suggested that dogs are able to recognise human faces, but conclusive evidence has yet to be found. Experiment 1 of this study investigated whether dogs can recognise humans using visual information from the face/head region, and whether this also occurs in conditions of suboptimal visibility of the face. Dogs were presented with t...
As faces become familiar, we come to rely more on their internal features for recognition and matching tasks. Here, we assess whether this same pattern is also observed for a card sorting task. Participants sorted photos showing either the full face, only the internal features, or only the external features into multiple piles, one pile per identit...
In our everyday lives, we are required to make decisions based upon our statistical intuitions. Often, these involve the comparison of two groups, such as luxury versus family cars and their suitability. Research has shown that the mean difference affects judgements where two sets of data are compared, but the variability of the data has only a min...
Matching unfamiliar faces is known to be difficult, and this can give an opportunity to those engaged in identity fraud. Here we examine a relatively new form of fraud, the use of photo-ID containing a graphical morph between two faces. Such a document may look sufficiently like two people to serve as ID for both. We present two experiments with hu...
Individual subject scores for each of the three experiments.
(XLSX)
When judging performances in a sequence, the current score is often influenced by the preceding score. Where athletes are perceived to be similar, a judgement is assimilated towards the previous one. However, if judges focus on the differences between the two athletes, this will result in a contrasting influence on their scores. Here, I investigate...
Judges' scores for all synchronised diving events at the 2012 and 2016 Olympic Games
Viewers are highly accurate at recognizing sex and race from faces-though it remains unclear how this is achieved. Recognition of familiar faces is also highly accurate across a very large range of viewing conditions, despite the difficulty of the problem. Here we show that computation of sex and race can emerge incidentally from a system designed...
We describe InterFace, a software package for research in face recognition. The package supports image warping, reshaping, averaging of multiple face images, and morphing between faces. It also supports principal components analysis (PCA) of face images, along with tools for exploring the “face space” produced by PCA. The package uses a simple grap...
We describe InterFace, a software package for research in face recognition. The package supports image warping, reshaping, averaging of multiple face images, and morphing between faces. It also supports principal components analysis (PCA) of face images, along with tools for exploring the “face space” produced by PCA. The package uses a simple grap...
Facial width-to-height ratio (FWHR), defined as the width of the face divided by the upper facial height, is a cue to behaviour. Explanations for this link often involve the idea that FWHR is sexually dimorphic, resulting from intersexual selection pressures. However, few studies have considered sexual dimorphism in skulls since the original paper...
We learn new faces throughout life, for example in everyday settings like watching TV. Recent research has shown that image variability is key to this ability: if we learn a new face over highly variable images, we are better able to recognize that person in novel pictures. Here we asked people to watch TV shows they had not seen before, and then t...
Forms of body decoration exist in all human cultures. However, in Western societies, women are more likely to engage in appearance modification, especially through the use of facial cosmetics. How effective are cosmetics at altering attractiveness? Previous research has hinted that the effect is not large, especially when compared to the variation...
Data from Study 1.
Each participant rated all 33 YouTube models, but each model appeared in a randomly selected cosmetics condition. All conditions are stated in the data. We averaged across participants for each image, building a score for each identity under both cosmetics conditions.
(XLS)
Data from Study 2.
Each participant rated all 45 supermodels, but each model appeared in a randomly selected cosmetics condition. All conditions are stated in the data. We averaged across participants for each image, building a score for each identity under both cosmetics conditions.
(XLS)
Data from the quantity raters in both studies.
Sheet 1 contains the quantity data from Study 1, and Sheet 2 contains the quantity data for Study 2. Participants compared each model without and with cosmetics, indicating how much cosmetics the faces were wearing.
(XLS)
As a mild-mannered reporter, Clark Kent is
able to blend into human society without
drawing much attention to himself. Although he
utilises several methods of disguise (clothing,
posture, hair style), perhaps his most famous is
a simple pair of glasses (see Figure 1). We know
that wearing glasses can make you look more
educated and intelligent (e.g...
Could a simple pair of glasses really fool us into thinking Superman and Clark Kent are two different people? Here, we investigated the perception of identity from face images with a task that relies on visual comparison rather than memory. Participants were presented with two images simultaneously and were asked whether the images depicted the sam...
Several studies have focused on how dogs use visual information about human faces, but their ability to recognize the faces of familiar people is not yet understood. We tested 30 dogs on their ability to recognize their owners by using face information alone. In a series of two-choice tasks, dogs had to choose between their owner and a stranger, wh...
Although several studies in recent years have provided evidence of a relationship between month of birth and height during childhood, the association remains less clear for adult (final) height. Here, I investigated this relationship using a large international sample of adult actors. Analyses considered both the sample as a whole, as well as subsa...
Research has demonstrated that wearing red can have significant effects on perceptions of the wearer. However, these findings are based on impressions formed while viewing static images. Here, I focus on perceptions of political leaders and show participants short videos in order to investigate color effects in stimuli with increased ecological val...
In recent years, researchers have investigated the relationship between facial width-to-height ratio (FWHR) and a variety of threat and dominance behaviours. The majority of methods involved measuring FWHR from 2D photographs of faces. However, individuals can vary dramatically in their appearance across images, which poses an obvious problem for r...
The vast majority of women in modern societies use facial cosmetics, which modify facial cues to attractiveness. However, the size of this increase remains unclear-how much more attractive are individuals after an application of cosmetics? Here, we utilised a 'new statistics' approach, calculating the effect size of cosmetics on attractiveness usin...