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 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

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

Thin gold films grown in ultra high vacuum on mica substrates

In-situ evaporation was used to deposit thin gold films (640 A) on mica substrates held at room temperature. The samples were characterized by Auger Electron Spectroscopy (AES) and Scanning Tunneling Microscopy (STM) measurements. The deposition of gold on mica without pre-anneal of the mica substrate resulted in a grainy surface with an average grain size of -220 A. The evolution of the average grain size as a function of mica pre-deposition baking time and deposition rate was investigated. It was found that long bake-outs (48 hours or more), and low deposition rates (0.2 A/s) increased the average dimension of gold grains by a factor of 5 relative to the films evaporated onto unannealed mica. Post-annealing a film deposited at room temperature promoted grain enlargement and enhanced (111) termination. The thermal annealing treatments were done at temperatures between 80 and 340°C, and for periods of time ranging from 1 to 12 hours. In addition to prolonged annealing, /n-s/fu flash annealing produced surfaces with highly crystalline terraces extending for as much as 5000 A. Flashing experiments were carried out at temperatures between 300 and 650°C. Below 350°C, flash annealed and as grown films were visually similar

Normal Acquisition of Expertise with Greebles in Two Cases of Acquired Prosopagnosia

Face recognition is generally thought to rely on different neurocognitive mechanisms than most types of objects, but the specificity of these mechanisms is debated. One account suggests the mechanisms are specific to upright faces, whereas the expertise view proposes the mechanisms operate on objects of high within-class similarity with which an observer has become proficient at rapid individuation. Much of the evidence cited in support of the expertise view comes from laboratory-based training experiments involving computer-generated objects called greebles that are designed to place face-like demands on recognition mechanisms. A fundamental prediction of the expertise hypothesis is that recognition deficits with faces will be accompanied by deficits with objects of expertise. Here we present two cases of acquired prosopagnosia, Herschel and Florence, who violate this prediction: Both show normal performance in a standard greeble training procedure, along with severe deficits on a matched face training procedure. Herschel and Florence also meet several response time criteria that advocates of the expertise view suggest signal successful acquisition of greeble expertise. Furthermore, Herschel’s results show that greeble learning can occur without normal functioning of the right fusiform face area, an area proposed to mediate greeble expertise. The marked dissociation between face and greeble expertise undermines greeble-based claims challenging face-specificity and indicates face recognition mechanisms are not necessary for object recognition after laboratory-based training

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

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

Gas Sensing Materials Based on TiO2 Thin Films

Ti O 2 thin films were prepared by spray pyrolysis using a solution of titanium tetrachloride and ethyl alcohol. The deposition was performed onto different substrates (silicon, quartz, glass) maintained at the same temperature, 270 ° C . After annealing, a predominant rutile structure is obtained for films deposited onto silicon and quartz substrates, as revealed by x-ray diffraction patterns. The Ti O 2 films were exposed to different gases, at different temperatures, in order to evaluate their gas sensitivity. The optimum operating temperatures, showing the highest gas sensitivity, were determined for some gases (acetone, ethanol, methane, and liquefied petroleum gas)