Social perception of faces: Neuropsychological and behavioural investigations

This thesis concerns theoretical and empirical issues in face processing and facial trait perception. First, I present evidence that challenges two hypotheses proposed as alternatives to face specificity, namely the individuation and the expertise hypotheses. Inconsistent with the individuation hypothesis, an extensive investigation of a new case of acquired prosopagnosia (Herschel) revealed normal exemplar recognition memory for a wide variety of objects, and normal ability to discriminate between highly similar items within a novel object category. Inconsistent with the expertise hypothesis, Herschel and Florence, a second acquired prosopagnosic, showed normal learning profiles and response times putative of successful expertise acquisition in an eight-day training procedure with novel objects, demonstrating that faces are processed by specialised mechanisms not used for objects-of-expertise. Second, testing four patients with acquired prosopagnosia, I demonstrate that perceptual mechanisms underlying trait judgments are dissociable from those implicated in recognising identity. Furthermore, I show that perception of facial aggressiveness does not depend on mechanisms for facial sex recognition, and that normal facial trustworthiness judgments are likely to occur without intact recognition of facial expressions, therefore challenging the overgeneralisation theory in facial trait perception. Third, I present a series of experiments with healthy participants to characterise various properties of facial trait perception. Specifically, I examine: i) the role of facial width-to-height ratio in perceived trustworthiness; ii) the accuracy of facial trustworthiness judgments; iii) the interaction between facial trustworthiness and reputation; and iv) the interaction between face impressions and voice impressions. Overall, the findings of the present thesis have important implications for the nature of the mechanisms underlying facial identity processing, the organisation of facial trait perception and its relationship to other face perception abilities, as well as the physical, ecological, and multimodal aspects of facial trait perception

The inversion, part-whole, and composite effects reflect distinct perceptual mechanisms with varied relationships to face recognition

Face recognition is thought to rely on specific mechanisms underlying a perceptual bias toward processing faces as undecomposable wholes. This face-specific "holistic processing" is commonly quantified using 3 measures: the inversion, part-whole, and composite effects. Consequently, many researchers assume that these 3 effects measure the same cognitive mechanism(s) and these mechanisms contribute to the wide range of individual differences seen in face recognition ability. We test these assumptions in a large sample (N = 282), with individual face recognition abilities measured by the well-validated Cambridge Face Perception Test. Our results provide little support for either assumption. The small to nonexistent correlations among inversion, part-whole, and composite effects (correlations between -.03 and .28) fail to support the first assumption. As for the second assumption, only the inversion effect moderately predicts face recognition (r = .42); face recognition was weakly correlated with the part-whole effect (r = .25) and not correlated with the composite effect (r = .04). We rule out multiple artifactual explanations for our results by using valid tasks that produce standard effects at the group level, demonstrating that our tasks exhibit psychometric properties suitable for individual differences studies, and demonstrating that other predicted correlations (e.g., between face perception measures) are robust. Our results show that inversion, part-whole, and composite effects reflect distinct perceptual mechanisms, and we argue against the use of the single, generic term holistic processing when referring to these effects. Our results also question the contribution of these mechanisms to individual differences in face recognition

The composite effect for inverted faces is reliable at large sample sizes and requires the basic face configuration

Abstract The absence of the face composite effect (FCE) for inverted faces is often considered evidence that holistic processing operates only on upright faces. However, such absence might be explained by power issues: Most studies that have failed to find the inverted FCE tested 24 participants or less. Here we find that the inverted FCE exists reliably when we tested at least 60 participants. The inverted FCE was ∼ 18% the size of the upright FCE, and it was unaffected by testing order: It did not matter whether participants did the upright condition first (Experiment 1, n = 64) or the inverted condition first (Experiment 2, n = 68). The effect also remained when upright and inverted trials were mixed (Experiment 3, n = 60). An individual differences analysis found a modest positive correlation between inverted and upright FCE, suggesting partially shared mechanisms. A critical control experiment demonstrates that the inverted FCE cannot be explained by visuospatial attention or other generic accounts because the effect disappeared when the basic face configuration was disrupted (Experiment 4, n = 50). Our study shows that the inverted FCE is a reliable effect that requires an intact face configuration, consistent with the notion that some holistic processing also operates on inverted faces

The development of upright face perception depends on evolved orientation-specific mechanisms and experience

Here we examine whether our impressive ability to perceive upright faces arises from evolved orientation-specific mechanisms, our extensive experience with upright faces, or both factors. To do so, we tested Claudio, a man with a congenital joint disorder causing his head to be rotated back so that it is positioned between his shoulder blades. As a result, Claudio has seen more faces reversed in orientation to his own face than matched to it. Controls exhibited large inversion effects on all tasks, but Claudio performed similarly with upright and inverted faces in both detection and identity-matching tasks, indicating these abilities are the product of evolved mechanisms and experience. In contrast, he showed clear upright superiority when detecting “Thatcherized” faces (faces with vertically flipped features), suggesting experience plays a greater role in this judgment. Together, these findings indicate that both evolved orientation-specific mechanisms and experience contribute to our proficiency with upright faces

How well do computer-generated faces tap face expertise?

The use of computer-generated (CG) stimuli in face processing research is proliferating due to the ease with which faces can be generated, standardised and manipulated. However there has been surprisingly little research into whether CG faces are processed in the same way as photographs of real faces. The present study assessed how well CG faces tap face identity expertise by investigating whether two indicators of face expertise are reduced for CG faces when compared to face photographs. These indicators were accuracy for identification of own-race faces and the other-race effect (ORE)-the well-established finding that own-race faces are recognised more accurately than other-race faces. In Experiment 1 Caucasian and Asian participants completed a recognition memory task for own- and other-race real and CG faces. Overall accuracy for own-race faces was dramatically reduced for CG compared to real faces and the ORE was significantly and substantially attenuated for CG faces. Experiment 2 investigated perceptual discrimination for own- and other-race real and CG faces with Caucasian and Asian participants. Here again, accuracy for own-race faces was significantly reduced for CG compared to real faces. However the ORE was not affected by format. Together these results signal that CG faces of the type tested here do not fully tap face expertise. Technological advancement may, in the future, produce CG faces that are equivalent to real photographs. Until then caution is advised when interpreting results obtained using CG faces

Self-Assembly Fabrication of Hollow Mesoporous Silica@Co–Al Layered Double Hydroxide@Graphene and Application in Toxic Effluents Elimination

Here, we propose a self-assembly process to prepare hierarchical HM-SiO2@Co–Al LDH@graphene, with the purpose of combining their outstanding performance. Hollow mesoporous silica was first synthesized as the core, using a novel sonochemical method, followed by a controlled shell coating process and chemical reduction. As a result of the electrostatic potential difference among HM-SiO2, Co–Al LDH, and graphene oxide, the HM-SiO2 spheres were coated by Co–Al LDH and graphene. Subsequently, the HM-SiO2@Co–Al LDH@graphene spheres were introduced into an epoxy resin (EP) matrix for investigation of their toxic effluents capture and elimination effectiveness during combustion. The amount of toxic CO and volatile organic compounds from the epoxy resin decomposition significantly suppressed after incorporating the HM-SiO2@Co–Al LDH@graphene hybrids, implying a reduced toxicity

Ignat M. “Nanostructured lanthanum manganite perovskites in catalyst applications

Finding less expensive alternatives to noble metals catalysts is vital for implementing catalytic combustion on a wide scale, and lead substituted lanthanum manganites are a promising option. Nanometer particles of La 0.6 Pb 0.4 MnO 3 and La 0.6 Pb 0.4 MnO 3 + 0.2MeO (where Me = Mg or Ca) with perovskite structure were prepared by self-combustion method followed by heat treatment at 1000 o C in air. The effects of excess divalent ions (Ca 2+ and Mg 2+ ) in La 0.6 Pb 0.4 MnO 3 manganite perovskite on the catalyst properties were investigated. The morphological and surface properties are of great importance in the catalyst activity. Structure, specific surface area and grain size were determined using XRD, nitrogen adsorption (BET) and SEM analysis. X-ray diffraction evidenced the crystallinity and the nanosize of the perovskite crystallites. Following Mg or Ca addition to La 0.6 Pb 0.4 MnO 3 , a decrease in the grain size was detected by SEM. Rather large values for specific surface areas were obtained (of about 8 m 2 /g).The perovskite manganite powders have been tested in the catalytic combustion of three diluted gases: acetone/air, ethanol/air and methanol/air. The experimental results revealed that it was possible to start the catalytic combustion of the gases over the surface of the three perovskite at much lower temperatures than catalyst-free combustion

The psychological construal of health behaviors

Introduction In order to optimize the effectiveness of behavior change interventions, we need to understand how the construal level – how we mentally represent or construe events or behaviors – influences health-related choices. Objective To examine the impact of mental construal on health decisions. Based on the Construal Level Theory, we predicted that people would give more weight to “cognitive considerations” when making a choice after being primed with the high-level perspective, whereas they would give higher weights to “sensory considerations” after being primed with the low-level perspective. Method In the first experiment, ninety-nine participants were primed with either high-level or low-level perspective across decision scenarios about vaccination and physical safety. The second experiment investigated nutrition decisions, which asked seventy participants to taste food that either had no label or was labelled “organic”. Organic label should prime high-level construal as it implies outcomes (e.g., product quality and healthiness) that are more distant in time and uncertain, in contrast with sensory dimensions (e.g. taste and appearance), which are immediately present. Participants rated cognitive and sensory considerations as well as action intentions. Results The first study revealed that after the priming with the high-level construal, cognitive considerations became more important than sensory considerations in predicting protective action intentions, whereas after priming with the low-level construal, sensory considerations became more important. The second study revealed that only sensory considerations predicted decisions to consume the non-labelled product and only the cognitive score predicted decisions to consume the organic-labelled product. Conclusion We demonstrated a moderating effect of construal-level mindset in health-protective decisions. We also discuss the implications for health promotion and policy, such as optimizing the effectiveness of behavior change interventions