Individual Differences in the Ability to Recognise Facial Identity Are Associated with Social Anxiety

Previous research has been concerned with the relationship between social anxiety and the recognition of face expression but the question of whether there is a relationship between social anxiety and the recognition of face identity has been neglected. Here, we report the first evidence that social anxiety is associated with recognition of face identity, across the population range of individual differences in recognition abilities. Results showed poorer face identity recognition (on the Cambridge Face Memory Test) was correlated with a small but significant increase in social anxiety (Social Interaction Anxiety Scale) but not general anxiety (State-Trait Anxiety Inventory). The correlation was also independent of general visual memory (Cambridge Car Memory Test) and IQ. Theoretically, the correlation could arise because correct identification of people, typically achieved via faces, is important for successful social interactions, extending evidence that individuals with clinical-level deficits in face identity recognition (prosopagnosia) often report social stress due to their inability to recognise others. Equally, the relationship could arise if social anxiety causes reduced exposure or attention to people's faces, and thus to poor development of face recognition mechanisms

Radio-optical flux behavior and spectral energy distribution of the intermediate blazar GC 0109+224

About twenty years of radio observations in five bands (from 4.8 to 37 GHz) of the BL Lac object GC 0109+224 (S2 0109+22, RGB J0112+227), are presented and analysed together with the optical data. Over the past ten years this blazar has exhibited enhanced activity. There is only weak correlation between radio and optical flares delays, usually protracted on longer timescales in the radio with respect to the optical. In some cases no radio flare counterpart was observed for the optical outbursts. The radio variability, characterised by peaks superposition, shows hints of some characteristic timescales (around the 3-4 years), and a fluctuation mode between the flickering and the shot noise. The reconstructed spectral energy distribution, poorly monitored at high energies, is preliminarily parameterised with a synchrotron-self Compton description. The smooth synchrotron continuum, peaked in the near-IR-optical bands, strengthens the hypothesis that this source could be an intermediate blazar. Moreover the intense flux in millimetre bands, and the optical and X-ray brightness, might suggest a possible detectable gamma-ray emission.Comment: 9 pages, 7 figures, 2 tables. Typeset with a LaTex2e-AMSLaTex code prepared by the author (using mn2e class, and natbib, hyperref, graphicx, packages). Accepted for publication in MNRA

Connecting object recognition performance, adaptation after effects, and form processing strategies in high-level vision

Psychophysical techniques such as adaptation after effects are commonly used to investigate face and object recognition, and have played an important role in the development of models of high-level visual shape coding. Yet the nature of the relationship between these behavioural effects and the underlying neuronal processes is currently unclear. An open question concerns the extent to which face and object after effects reflect the properties of high-level shape coding, as opposed to other stages of visual processing. A related question concerns what aspects of high-level coding can be inferred from after effects. This thesis reports four psychophysical investigations of face and object recognition, high-level shape coding, and adaptation after effects in high-level form vision. The first study introduces a new test of within-class object recognition-the Cambridge Car Memory Test-and provides norms for the test based on a sample of 153 young adults. The second study investigated whether face eye-height after effects would be correlated with face recognition ability, based on the theoretical notion that face after effect magnitude should reflect the sensitivity of neuronal face-space coding. Results showed a modest but significant correlation between face eye-height after effects and recognition ability, arguing that eye-height after effects can tap processes which contribute to face recognition ability. The third study investigated the extent to which global face distortion after effects tap face-level processes, as opposed to shape-generic processes. Results showed complete transfer of after effects from a scrambled face adaptor to non-face test stimuli, but only partial transfer from an intact face adaptor to non-face test stimuli, arguing that global face distortion after effects have both face-specific and shape-generic components.The final study investigated the coding strategy underlying perception of horse shape and tested whether adaptation to horses can enhance subsequent discriminability of horse shape. Results were consistent with norm-based coding with linear response functions and showed that adaptation to horses can improve discriminability of horse shape. In sum, the evidence reported in this thesis argues that face and object after effects can be a useful method of investigating high-level visual shape coding, but that these effects should be interpreted with caution given that they will generally reflect the combined activity of multiple stages of processing

Global face distortion aftereffects tap face-specific and shape-generic processes

Face aftereffects are commonly used to investigate the mechanisms underlying face processing, based on the assumption that they tap processes involved specifically with face-level coding (e.g., face space). However, face aftereffects could potentially arise from many levels of the visual system, and recent research has shown that one figural aftereffect (eye height) has both face-level and shape-generic components. Another very widely used figural manipulation is global face distortion. Here we investigate whether a global face distortion aftereffect (vertical compression) transfers to nonface stimuli, and if so, to what extent. Arguing for a mid- or high-level shape-generic component to our face aftereffect, we found significant face-to-object transfer even after minimizing retinotopic components. Arguing for an additional face-specific component, we found, first, that face-to-face aftereffects were significantly larger than face-to-object aftereffects and second, that this occurred only when the adaptor face was whole and intact rather than scrambled. Our results argue that global face distortion aftereffects are a useful tool for investigating face-space but that, to do so unambiguously, requires developing methods to minimize or account for the shape-generic contribution

Face Aftereffects Predict Individual Differences in Face Recognition Ability

Face aftereffects are widely studied on the assumption that they provide a useful tool for investigating face-space coding of identity. However, a long-standing issue concerns the extent to which face aftereffects originate in face-level processes as opposed to earlier stages of visual processing. For example, some recent studies failed to find atypical face aftereffects in individuals with clinically poor face recognition. We show that in individuals within the normal range of face recognition abilities, there is an association between face memory ability and a figural face aftereffect that is argued to reflect the steepness of broadband-opponent neural response functions in underlying face-space. We further show that this correlation arises from face-level processing, by reporting results of tests of nonface memory and nonface aftereffects. We conclude that face aftereffects can tap high-level face-space, and that face-space coding differs in quality between individuals and contributes to face recognition ability

The Cambridge Car Memory Test: A task matched in format to the Cambridge Face Memory Test, with norms, reliability, sex differences, dissociations from face memory, and expertise effects

Many research questions require a within-class object recognition task matched for general cognitive requirements with a face recognition task. If the object task also has high internal reliability, it can improve accuracy and power in group analyses (e

Substituting depth for intensity and real-time phosphene rendering: Visual navigation under low vision conditions

Navigation and way finding including obstacle avoidance is difficult when visual perception is limited to low resolution, such as is currently available on a bionic eye. Depth visualisation may be a suitable alternative. Such an approach can be evaluate

Substituting depth for intensity and real-time phosphene rendering: visual navigation under low vision conditions

Navigation and way finding including obstacle avoidance is difficult when visual perception is limited to low resolution, such as is currently available on a bionic eye. Depth visualisation may be a suitable alternative. Such an approach can be evaluated using simulated phosphenes with a wearable mobile virtual reality kit. In this paper, we present two novel approaches: (i) an implementation of depth visualisation; and, (ii) novel methods for rapid rendering of simulated phosphenes with an empirical comparison between them. Our new software-based method for simulated phosphene rendering shows large speed improvements, facilitating the display in real-time of a large number of phosphenes with size and brightness dependent on pixel intensity, and with customised output dynamic range. Further, we describe the protocol, navigation environment and system used for visual navigation experiments to evaluate the use of depth on low resolution simulations of a bionic eye perceptual experience. Results for these experiments show that a depth-based representation is effective for navigation, and shows significant advantages over intensity-based approaches when overhanging obstacles are present. The results of the experiments were reported in [1], [2]

Face recognition impairments despite normal holistic processing and face space coding: Evidence from a case of developmental prosopagnosia

Holistic processing and face space coding are widely considered primary perceptual mechanisms behind good face recognition. Here, however, we present the case of S.P., a developmental prosopagnosic who demonstrated severe impairments in face memory and face perception, yet showed normal holistic processing and face space coding. Across three composite experiments, S.P. showed normalstrength holistic processing for upright faces and no composite effect for inverted faces. Across five aftereffect experiments, S.P. showed normal-sized face aftereffects, which derived normally from face space rather than shape-generic mechanisms. The case of S.P. implies: (a) normal holistic processing and face space coding can be insufficient for good face recognition even when present in combination; and (b) the focus of recent literature on holistic processing and face space should be expanded to include other potential face processing mechanisms (e.g., part-based processing). Our article also highlights the importance of internal task reliability in drawing inferences from single-case studies