Ce travail s'intéresse à l'effet de la catégorisation raciale et de genre dans la mémoire des visages. Les études effectuées montrent que la première induit une polarisation de la seconde. Ainsi, des visages catégorisés dans une catégorie particulière sont rappelés comme plus typiques de leur catégorie et moins typiques de catégories alternatives. Cet effet est observé à la fois dans le cas de visages fortement ambigus catégorisés sur base du contexte et dans le cas de visages modérément ambigus catégorisés sur base de leurs traits. Les implications pratiques et théoriques de ces résultats sont discutées.

Ce travail s'intéresse à l'effet de la catégorisation raciale et de genre dans la mémoire des visages. Les études effectuées montrent que la première induit une polarisation de la seconde. Ainsi, des visages catégorisés dans une catégorie particulière sont rappelés comme plus typiques de leur catégorie et moins typiques de catégories alternatives. Cet effet est observé à la fois dans le cas de visages fortement ambigus catégorisés sur base du contexte et dans le cas de visages modérément ambigus catégorisés sur base de leurs traits. Les implications pratiques et théoriques de ces résultats sont discutées.

It is important to establish the role of age in face-processing since perceived-age is a dimension that may be used to encode faces within memory. While previous research has demonstrated faces can be categorised by age, a question that has not been addressed is how well people are able to do so. This study identifies the extent to which people can categorise faces on the basis of age and also explores the nature of the visual information used for this. The evidence suggests that age-perception is much more complex than has been previously suggested. Using realistic faces as stimuli, it becomes apparent that people are adept at using a wide variety of cues to age. Overall, this demonstrates that we have a sophisticated understanding of the changes that occur through ageing, that we can use with a high degree of subtlety and accuracy. Given the robust nature of information about age and the ability to which it can be used to differentiate faces, age must be influential at encoding. However, the ability to determine and encode a face's physical properties at one point in time can not be a full explanation for the way faces are represented simply because those physical properties do not stay the same over time. The ageing face can therefore be used as a tool to gain greater insight into what facial information is utilised for individual recognition. This was investigated using a recognition paradigm where the individual faces were of different ages to those initially presented and hence displayed different physical properties. The evidence shows that recognition despite age-induced changes is possible; this implies that there is not a one to one mapping between the physical properties at encoding and those that the memory system operates on to accomplish recognition.

The present thesis investigates whether the emotional background (context) in which a neutral face is viewed changes one’s memory for that face. In Experiment 1, neutral faces were overlaid centrally onto emotional (positive or negative) or neutral background scenes, and recognition memory for faces was assessed. Memory for faces initially encoded in negative contexts was boosted relative to memory for faces initially encoded in neutral contexts. Further investigation was necessary to reveal the mechanism behind the influence that emotional context had on memory for faces. In Experiments 2 and 3 the spotlight theory of attention was tested to examine whether visual attention was mediating the memory effect. The spotlight theory of attention postulates that positive affective states broaden one’s scope of attention, while negative affective states narrow one’s scope of attention (Easterbrook, 1959; Derryberry & Tucker, 1994). According to this theory, the negative contexts may have narrowed attentional scope and therefore led to a richer processing of the face which happened to be presented centrally in Experiment 1, leading to boosted recognition of these faces. To test whether the varying emotional contexts did indeed shift attentional scope, Experiment 2 was designed in which neutral faces were presented once again in positive, negative or neutral contexts, however location of face presentation was peripheral rather than central. Results revealed a loss of the memory boost, for faces paired with negative contexts, reported in Experiment 1. Experiment 3 was designed to test the spotlight theory of attention using an intermixed design in which faces were presented either centrally or peripherally, randomly across trials, in emotional and neutral background scenes. In this experiment, faces were better remembered when they were viewed peripherally in positive, relative to neutral, contexts at time of study. Experiment 4 was designed to assess the validity of the spotlight theory in accounting for how emotional scenes change visual attention, by examining how performance on a flanker task differed when emotionally positive or negative scenes were presented centrally. Results suggest that positive scenes broaden the spotlight of attention, relative to negatives ones. In summary, emotional contexts lead to a boost in memory for faces paired with negative information, and this effect may be due to shifts in attention varied by the valence of the context.

The present thesis investigates whether the emotional background (context) in which a neutral face is viewed changes one’s memory for that face. In Experiment 1, neutral faces were overlaid centrally onto emotional (positive or negative) or neutral background scenes, and recognition memory for faces was assessed. Memory for faces initially encoded in negative contexts was boosted relative to memory for faces initially encoded in neutral contexts. Further investigation was necessary to reveal the mechanism behind the influence that emotional context had on memory for faces. In Experiments 2 and 3 the spotlight theory of attention was tested to examine whether visual attention was mediating the memory effect. The spotlight theory of attention postulates that positive affective states broaden one’s scope of attention, while negative affective states narrow one’s scope of attention (Easterbrook, 1959; Derryberry & Tucker, 1994). According to this theory, the negative contexts may have narrowed attentional scope and therefore led to a richer processing of the face which happened to be presented centrally in Experiment 1, leading to boosted recognition of these faces. To test whether the varying emotional contexts did indeed shift attentional scope, Experiment 2 was designed in which neutral faces were presented once again in positive, negative or neutral contexts, however location of face presentation was peripheral rather than central. Results revealed a loss of the memory boost, for faces paired with negative contexts, reported in Experiment 1. Experiment 3 was designed to test the spotlight theory of attention using an intermixed design in which faces were presented either centrally or peripherally, randomly across trials, in emotional and neutral background scenes. In this experiment, faces were better remembered when they were viewed peripherally in positive, relative to neutral, contexts at time of study. Experiment 4 was designed to assess the validity of the spotlight theory in accounting for how emotional scenes change visual attention, by examining how performance on a flanker task differed when emotionally positive or negative scenes were presented centrally. Results suggest that positive scenes broaden the spotlight of attention, relative to negatives ones. In summary, emotional contexts lead to a boost in memory for faces paired with negative information, and this effect may be due to shifts in attention varied by the valence of the context.

The distinctiveness of a face is a crucial factor for its ability to be discriminated, memorized, and identified correctly. In this thesis, we provided a contribution to face distinctiveness by examining the impact of socially relevant factors such as attractiveness, group and emotional expression on distinctiveness. We show that attractive faces are more similar to each other than unattractive faces, using female Caucasian faces and male faces of a Caucasian and heterogeneous Non-Caucasian group. We also show, using 3D face generated faces of photo-realistic quality, that attractive faces were closer to the prototype of only their specific group, and that hence typicality of attractive faces was group specific. Lastly, we show that assigning an emotional expression to a face that is evaluatively incongruent with its race makes it more psychologically distinctive, as revealed in perceptual discrimination and memory tasks.

The distinctiveness of a face is a crucial factor for its ability to be discriminated, memorized, and identified correctly. In this thesis, we provided a contribution to face distinctiveness by examining the impact of socially relevant factors such as attractiveness, group and emotional expression on distinctiveness. We show that attractive faces are more similar to each other than unattractive faces, using female Caucasian faces and male faces of a Caucasian and heterogeneous Non-Caucasian group. We also show, using 3D face generated faces of photo-realistic quality, that attractive faces were closer to the prototype of only their specific group, and that hence typicality of attractive faces was group specific. Lastly, we show that assigning an emotional expression to a face that is evaluatively incongruent with its race makes it more psychologically distinctive, as revealed in perceptual discrimination and memory tasks.

In eyewitness identification cases, suspect misidentification is the leading factor attributed to wrongful convictions (Scheck, Neufeld, & Dwyer, 2000), thus, it is of applied importance to identify factors that contribute to the false recollection of faces. One potential factor addressed in the current study was whether face memory and subsequent identification for other-race-faces is biased by the degree to which a target face posses facial features associated with ethnic identity. Individual differences in level of processing (global, local) and prejudice were tested as potential mechanisms contributing to biased judgments. In Experiment 1 a standard face recognition task revealed that prejudice, level of processing, and face-type interacted to predict recognition bias. In Experiment 2 results showed that positive misidentifications (i.e., choosing an incorrect foil) were more likely when a stereotypical versus non-stereotypical Black actor was witnessed committing the crime. Results are discussed in terms of theoretical and practical implications.

The own-group bias in face recognition (OGB) is the greater facility to distinguish and recognize people from one's own group at the expense of people from other-groups. The OGB has been studied for many years, however, very little research focuses on finding a way to decrease or eliminate it, through training. Reporting five studies involving memory or matching tasks, the aim of the present thesis was to develop and to explore to what extent training can decrease or remove the OGB. French White participants, and South African White, Black and Coloured participants took part in different studies, using Black and White faces as stimuli. In each study, White participants from both countries presented the expected OGB prior to any intervention. However, the presence of the OGB in South African Black participants was detected only in one (matching task) study, instead recording a higher discrimination performance by Black participants for White faces in the other studies. As expected, South African Coloured participants did not display increased discrimination performance for any of the other stimuli groups, both being out-group stimuli. Results from the training studies revealed either (a) no effect of a distributed training in feature focus over 5 weeks; (b) an increase of the OGB after a focus on critical facial features; (c) a decrease of the OGB in a task-specific training using pictures whose quality had been manipulated, and; (d) an important implication of the presence/absence of the target in a field detection study. With some promising results, the present work contributes to our understanding of how training could be used to improve face-recognition, and especially other-group face recognition.

No description available.