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

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

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

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

Detecting morphed passport photos : a training and individual differences approach

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

Molecular phylogeny of the Achatinoidea (Mollusca: Gastropoda)

This study presents a multi-gene phylogenetic analysis of the Achatinoidea and provides an initial basis for a taxonomic re-evaluation of family level groups within the superfamily. A total of 5028 nucleotides from the nuclear rRNA, actin and histone 3 genes and the 1st and 2nd codon positions of the mitochondrial cytochrome c oxidase subunit I gene were sequenced from 24 species, representing six currently recognised families. Results from maximum likelihood, neighbour joining, maximum parsimony and Bayesian inference trees revealed that, of currently recognised families, only the Achatinidae are monophyletic. For the Ferussaciidae, Ferussacia folliculus fell separately to Cecilioides gokweanus and formed a sister taxon to the rest of the Achatinoidea. For the Coeliaxidae, Coeliaxis blandii and Pyrgina umbilicata did not group together. The Subulinidae was not resolved, with some subulinids clustering with the Coeliaxidae and Thyrophorellidae. Three subfamilies currently included within the Subulinidae based on current taxonomy likewise did not form monophyletic groups

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

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

The masses of the cataclysmic variables AC Cancri and V363 Aurigae

We present time-resolved spectroscopy and photometry of the double-lined eclipsing cataclysmic variables AC Cnc and V363 Aur (= Lanning 10). There is evidence of irradiation on the inner hemisphere of the secondary star in both systems, which we correct for using a model that reproduces the observations remarkably well. We find the radial velocity of the secondary star in AC Cnc to be KR= 176 ± 3 km s−1 and its rotational velocity to be v sin i= 135 ± 3 km s−1. From these parameters we obtain masses of M1= 0.76 ± 0.03 M⊙ for the white-dwarf primary and M2= 0.77 ± 0.05 M⊙ for the K2 ± 1V secondary star, giving a mass ratio of q= 1.02 ± 0.04. We measure the radial and rotational velocities of the G7 ± 2V secondary star in V363 Aur to be KR= 168 ± 5 km s−1 and v sin i= 143 ± 5 km s−1, respectively. The component masses of V363 Aur are M1= 0.90 ± 0.06 M⊙ and M2= 1.06 ± 0.11 M⊙, giving a mass ratio of q= 1.17 ± 0.07. The mass ratios for AC Cnc and V363 Aur fall within the theoretical limits for dynamically and thermally stable mass transfer. Both systems are similar to the SW Sex stars, exhibiting single-peaked emission lines with transient absorption features, high-velocity S-wave components and phase-offsets in their radial-velocity curves. The Balmer lines in V363 Aur show a rapid increase in flux around phase 0 followed by a rapid decrease, which we attribute to the eclipse of an optically thick region at the centre of the disc. This model could also account for the behaviour of other SW Sex stars where the Balmer lines show only a shallow eclipse compared to the continuum

Amplification and stability of magnetic fields and dynamo effect in young A stars

This study is concerned with the early evolution of magnetic fields and differential rotation of intermediate-mass stars which may evolve into Ap stars. We report on simulations of the interplay of differential rotation and magnetic fields, the stability limits and non-linear evolution of such configurations, and the prospects of dynamo action from the unstable cases. The axisymmetric problem delivers a balance between field amplification and back-reaction of the magnetic field on the differential rotation. The non-axisymmetric case involves also the Tayler instability of the amplified toroidal fields. We consider limits for field amplification and apply these to young A stars. Apart from its application to Ap stars, the instability is scrutinized for the fundamental possibility of a dynamo. We are not looking for a dynamo as an explanation for the Ap star phenomenon. The kinetic helicity is concentrated near the tangent cylinder of the inner sphere of the computational domain and is negative in the northern hemisphere. This appears to be a ubiquitous effect not special to the Tayler instability. The latter is actually connected with a positive current helicity in the bulk of the spherical shell giving rise to a small, but non-vanishing alpha-effect in non-linear evolution of the instability.Comment: 13 pages, 14 figures, accepted by Mon. Not. R. Astro