500 research outputs found

    Can people identify original and manipulated photos of real-world scenes?

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    Advances in digital technology mean that the creation of visually compelling photographic fakes is growing at an incredible speed. The prevalence of manipulated photos in our everyday lives invites an important, yet largely unanswered, question: Can people detect photo forgeries? Previous research using simple computer-generated stimuli suggests people are poor at detecting geometrical inconsistencies within a scene. We do not know, however, whether such limitations also apply to real-world scenes that contain common properties that the human visual system is attuned to processing. In two experiments we asked people to detect and locate manipulations within images of real-world scenes. Subjects demonstrated a limited ability to detect original and manipulated images. Furthermore, across both experiments, even when subjects correctly detected manipulated images, they were often unable to locate the manipulation. People’s ability to detect manipulated images was positively correlated with the extent of disruption to the underlying structure of the pixels in the photo. We also explored whether manipulation type and individual differences were associated with people’s ability to identify manipulations. Taken together, our findings show, for the first time, that people have poor ability to identify whether a real-world image is original or has been manipulated. The results have implications for professionals working with digital images in legal, media, and other domains

    Myelin Characteristics of the Corpus Callosum in Capuchin Monkeys (\u3cem\u3eSapajus\u3c/em\u3e [\u3cem\u3eCebus\u3c/em\u3e] \u3cem\u3eapella\u3c/em\u3e) Across the Lifespan

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    The midsagittal area of the corpus callosum (CC) is frequently studied in relation to brain development, connectivity, and function. Here we quantify myelin characteristics from electron microscopy to understand more fully differential patterns of white matter development occurring within the CC. We subdivided midsagittal regions of the CC into: I—rostrum and genu, II—rostral body, III—anterior midbody, IV—posterior midbody, and V—isthmus and splenium. The sample represented capuchin monkeys ranging in age from 2 weeks to 35 years (Sapajus [Cebus] apella, n = 8). Measurements of myelin thickness, myelin fraction, and g-ratio were obtained in a systematic random fashion. We hypothesized there would be a period of rapid myelin growth within the CC in early development. Using a locally weighted regression analysis (LOESS), we found regional differences in myelin characteristics, with posterior regions showing more rapid increases in myelin thickness and sharper decreases in g-ratio in early development. The most anterior region showed the most sustained growth in myelin thickness. For all regions over the lifespan, myelin fraction increased, plateaued, and decreased. These results suggest differential patterns of nonlinear myelin growth occur early in development and well into adulthood in the CC of capuchin monkeys

    Investigating age-related differences in ability to distinguish between original and manipulated images

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    Manipulated images can have serious and persistent ramifications across many domains: They have undermined trust in political campaigns, incited fear and violence, and fostered dangerous global movements. Despite growing concern about the power of manipulated images to influence people’s beliefs and behavior, few studies have examined whether people can detect manipulations and the psychological processes underpinning this task. We asked 5,291 older adults, 5,291 middle-aged adults, and 5,291 young adults to detect and locate manipulations within images of real-world scenes. To determine whether a simple intervention could improve people’s ability to detect manipulations, some participants viewed a short video which described the five common manipulation techniques used in the present study. Overall, participants demonstrated a limited ability to distinguish between original and manipulated images. Older adults were less accurate in detecting and locating manipulations than younger and middle-aged adults, and the effect of age varied by manipulation type. The video intervention improved performance marginally. Participants were often overconfident in their decisions, despite having limited ability to detect manipulations. Older adults were more likely than younger and middle-aged adults to report checking for shadow/lighting inconsistencies, a strategy that was not associated with improved discriminability, and less likely to report using other strategies (e.g., photometric inconsistencies) that were associated with improved discriminability. Differences in strategy use might help to account for the age differences in accuracy. Further research is needed to advance our understanding of the psychological mechanisms underlying image manipulation detection and the myriad factors that may enhance or impair performance

    Transactional data structures

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    Concurrent programming is difficult and the effort is rarely rewarded by faster execution. The concurrency problem arises because information cannot pass instantly between processors resulting in temporal uncertainty. This thesis explores the idea that immutable data and distributed concurrency control can be combined to allow scalable concurrent execution and make concurrent programming easier. A concurrent system that does not impose a global ordering on events lends itself to a scalable distributed implementation. A concurrent programming environment in which the ordering of events affecting an object is enforced locally has intuitive concurrent semantics. This thesis introduces Transactional Data Structures which are data structures that permit access to past versions, although not all accesses succeed. These data structures form the basis of a concurrent programming solution that supports database type transactions in memory. Transactional Data Structures permit non-blocking concurrent access to familiar abstract data types such as deques, maps, vectors and priority queues. Using these data structures a programmer can write a concurrent program in C without having to reason about locks. The solution is evaluated by comparing the performance of a concurrent algorithm to calculate the minimum spanning tree of a graph with that of a similar algorithm which uses Transactional Memory and by comparing a non-blocking Producer Consumer Queue with its blocking counterpart.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Attitudes and perceptions of professionals to anticoagulation: warfarin versus novel/direct oral anticoagulants [Oral Presentation]

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    Introduction: The National Institute for Health and Care Excellence (NICE) recommended direct oral anticoagulants (DOACs) for a variety of indications as equal alternatives to warfarin, and stated that the patient's values and preferences should be used to guide choice of agent in a shared decision making process [1]. However, uptake of DOACs had been patchy and slow across the UK [2]. Identifying the perceived barriers to using DOACs could help to develop strategies to overcome these and enable their use where appropriate. Aim: The study aimed to investigate the attitudes and perceptions of professionals towards oral anticoagulation, and the choice between warfarin and the DOACs. References 1. National Institute for Health and Care Excellence. Anticoagulants, including non-vitamin K antagonist oral anticoagulants (NOACs). Key therapeutic topic [KTT16]. 2016. Available at: https://www.nice.org.uk/advice/ktt16 [accessed 27/08/2019] 2. Association of the British Pharmaceutical Industry Stroke in Atrial Fibrillation Initiative. NOACs: Innovation in anticoagulation – Optimising the prevention of AF-related stroke. 2014. Available at: http://www.abpi.org.uk/publications/noacs-innovation-in-anticoagulation/ [accessed 27/08/2019

    Detecting morphed passport photos : a training and individual differences approach

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    Our reliance on face photos for identity verification is at odds with extensive research which shows that matching pairs of unfamiliar faces is highly prone to error. This process can therefore be exploited by identity fraudsters seeking to deceive ID checkers (e.g. using a stolen passport which contains an image of similar looking individual to deceive border control officials). In this study we build on previous work which sought to quantify the threat posed by a relatively new type of fraud - morphed passport photos. Participants were initially unaware of the presence of morphs in a series of face photo arrays, and were simply asked to detect which images they thought had been digitally manipulated (i.e. “images that didn’t look quite right”). All participants then received basic information on morph fraud and rudimentary guidance on how to detect such images, followed by a morph detection training task (Training Group, N = 40), or a non-face control task (Guidance Group, N = 40). Participants also completed a post-guidance/training morph detection task, and the Models Face Matching Test (MFMT). Our findings show that baseline morph detection rates were poor, that morph detection training significantly improved the identification of these images over and above basic guidance, and accuracy on the mismatch condition of the MFMT correlated with morph detection ability. The results are discussed in relation to potential counter-measures for morph-based identity fraud

    Investigating age-related differences in ability to distinguish between original and manipulated images

    Get PDF
    Manipulated images can have serious and persistent ramifications across many domains: They have undermined trust in political campaigns, incited fear and violence, and fostered dangerous global movements. Despite growing concern about the power of manipulated images to influence people’s beliefs and behavior, few studies have examined whether people can detect manipulations and the psychological processes underpinning this task. We asked 5,291 older adults, 5,291 middle-aged adults, and 5,291 young adults to detect and locate manipulations within images of real-world scenes. To determine whether a simple intervention could improve people’s ability to detect manipulations, some participants viewed a short video which described the five common manipulation techniques used in the current study. Overall, participants demonstrated a limited ability to distinguish between original and manipulated images. Older adults were less accurate in detecting and locating manipulations than younger and middle-aged adults, and the effect of age varied by manipulation type. The video intervention improved performance marginally. Participants were often over-confident in their decisions, despite having limited ability to detect manipulations. Older adults were more likely than younger and middle-aged adults to report checking for shadow/lighting inconsistencies, a strategy that was not associated with improved discriminability, and less likely to report using other strategies (e.g., photometric inconsistencies) that were associated with improved discriminability. Differences in strategy use might help to account for the age differences in accuracy. Further research is needed to advance our understanding of the psychological mechanisms underlying image manipulation detection and the myriad factors that may enhance or impair performance

    Age-Related Changes in Myelin of Axons of the Corpus Callosum and Cognitive Decline in Common Marmosets

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    Executive control is a higher‐level cognitive function that involves a range of different processes that are involved in the planning, coordination, execution, and inhibition of responses. Many of the processes associated with executive control, such as response inhibition and mental flexibility, decline with age. Degeneration of white matter architecture is considered to be the one of the key factors underlying cognitive decline associated with aging. Here we investigated how white matter changes of the corpus callosum were related to cognitive aging in common marmosets (Callithrix jacchus). We hypothesized that reduction in myelin thickness, myelin density, and myelin fraction of axonal fibers in the corpus callosum would be associated with performance on a task of executive function in a small sample of geriatric marmosets (n = 4) and young adult marmosets (n = 2). Our results indicated declines in myelin thickness, density, and myelin fraction with age. Considerable variability was detected on these characteristics of myelin and cognitive performance assessed via the detoured reach task. Age‐related changes in myelin in Region II of the corpus callosum were predictive of cognitive performance on the detoured reach task. Thus the detoured reach task appears to also measure aspects of corticostriatal function in addition to prefrontal cortical function

    Caught virtually lying – crime scenes in virtual reality help to expose suspects' concealed recognition

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    We explore how virtual reality could be used in police investigations to take a suspect ‘back in time’ and demonstrate that they recognize a crime scene despite claiming not to. In this study, participants committed a mock crime before being incentivized to conceal recognition of crime related details (e.g., the stolen item or crime scene). The crime scenes and objects were laser scanned, converted to photo-realistic models, and presented to suspects either in Virtual Reality (VR) or as 2D images on a computer screen. While concealing recognition of crime information, participants’ heart rate and skin conductance were measured using a Concealed Information Test (CIT) to assess recognition. Detection of concealed recognition increased by over 25% when participants viewed crime items in VR compared to 2D images. Our findings suggest that revisiting crime scenes or objects in VR may enhance stimulus recognition and salience resulting in increased CIT diagnosticity
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