TY - BOOK

T1 - Visual Illusions as a Tool to Study Context Integration and Pictorial Depth Perception Across Methods, Expertise, and Lifespan

AU - Wincza, Radoslaw

PY - 2025

Y1 - 2025

N2 - Visual illusions (VIs) offer a unique lens through which one can explore human context integration and pictorial depth perception. Previously VIs have been used to, for example, uncover deficits in context integration in schizophrenia, as well as its development in children, or differences between vision for action and vision for perception. In this thesis, it was intended to investigate methodological discrepancies observed in previous research, as well as the role of expertise, sex and development across lifespan in susceptibility to VIs. In doing so, this doctoral thesis presents the inaugural systematic review of children's susceptibility to VIs (Chapter II). It reveals that children's susceptibility to certain VIs, such as the Ebbinghaus and Ponzo illusions increases with age, but decreases for the Muller-Lyer, Poggendorff, and Vertical-Horizontal illusions. Furthermore, it underscores the possibility that children’s responses are likely influenced by response biases. Moreover, it highlights that many previous findings in the field are contingent upon the specific methodologies and stimuli employed. However, a consistent developmental trend emerges with the Muller-Lyer illusion across various experimental conditions. Experiments I and II (Chapters III and IV) delve into methodological disparities between children and adults. In Experiment I, across two different methods, children were not shown to be less susceptible to the Ebbinghaus illusion compared to adults. However, in Experiment II, it was demonstrated that differing methodologies can yield disparate results across sexes. Notably, during Ebbinghaus illusion testing, males exhibit diminished susceptibility to this illusion, particularly under a specific version of the 2-alternative forced-choice method. Additionally, there is a substantial difference in the magnitude of the Muller-Lyer illusion when assessed via the method of adjustment versus the 2-alternative forced-choice method, with greater susceptibility observed in the former. Experiment 3 in Chapter V examines the influence of visual expertise, which was argued to be a potential factor shaping children’s susceptibility in the systematic review. We studied radiologists’ and radiographers’ susceptibility to a range of geometrical VIs, including the Ebbinghaus and Ponzo. This sample was selected as medical image interpretation relies on strong perceptual skills, which were hypothesised to be linked to VI susceptibility. The findings suggest that individuals with visual expertise in medical image interpretation are less prone to VIs, underscoring the significance of expertise in context integration and pictorial depth perception. Finally, following the insights from the systematic review regarding the role of brain changes in susceptibility to VIs, Experiment 4 in Chapter VI explores the connection between Parkinson's disorder – which manifests specific brain abnormalities including basal ganglia dysfunction and dopamine reduction — and visual anomalies. Collectively, it was observed that context integration remains intact in Parkinson’s disorder, suggesting that basal ganglia and dopamine (which are compromised in this condition) are not linked to VI susceptibility. Collectively, the discoveries in this thesis hold profound implications for advancing our understanding of context integration, pictorial depth perception, and the broader field of VI research. Firstly, it urges future research to consider the methodology in use, and its implications for the obtained findings. Furthermore, findings regarding susceptibility trends ought to be revisited, as context integration and pictorial depth perception are likely to develop before the age of seven years. Finally, the findings concerning reduced susceptibility to VIs amongst experts in medical image interpretation suggest that alongside changes in top-down perception, the training and expertise of radiologists and radiographers also lead to changes in bottom-up perception – as manifested by their reduced VIs susceptibility.

AB - Visual illusions (VIs) offer a unique lens through which one can explore human context integration and pictorial depth perception. Previously VIs have been used to, for example, uncover deficits in context integration in schizophrenia, as well as its development in children, or differences between vision for action and vision for perception. In this thesis, it was intended to investigate methodological discrepancies observed in previous research, as well as the role of expertise, sex and development across lifespan in susceptibility to VIs. In doing so, this doctoral thesis presents the inaugural systematic review of children's susceptibility to VIs (Chapter II). It reveals that children's susceptibility to certain VIs, such as the Ebbinghaus and Ponzo illusions increases with age, but decreases for the Muller-Lyer, Poggendorff, and Vertical-Horizontal illusions. Furthermore, it underscores the possibility that children’s responses are likely influenced by response biases. Moreover, it highlights that many previous findings in the field are contingent upon the specific methodologies and stimuli employed. However, a consistent developmental trend emerges with the Muller-Lyer illusion across various experimental conditions. Experiments I and II (Chapters III and IV) delve into methodological disparities between children and adults. In Experiment I, across two different methods, children were not shown to be less susceptible to the Ebbinghaus illusion compared to adults. However, in Experiment II, it was demonstrated that differing methodologies can yield disparate results across sexes. Notably, during Ebbinghaus illusion testing, males exhibit diminished susceptibility to this illusion, particularly under a specific version of the 2-alternative forced-choice method. Additionally, there is a substantial difference in the magnitude of the Muller-Lyer illusion when assessed via the method of adjustment versus the 2-alternative forced-choice method, with greater susceptibility observed in the former. Experiment 3 in Chapter V examines the influence of visual expertise, which was argued to be a potential factor shaping children’s susceptibility in the systematic review. We studied radiologists’ and radiographers’ susceptibility to a range of geometrical VIs, including the Ebbinghaus and Ponzo. This sample was selected as medical image interpretation relies on strong perceptual skills, which were hypothesised to be linked to VI susceptibility. The findings suggest that individuals with visual expertise in medical image interpretation are less prone to VIs, underscoring the significance of expertise in context integration and pictorial depth perception. Finally, following the insights from the systematic review regarding the role of brain changes in susceptibility to VIs, Experiment 4 in Chapter VI explores the connection between Parkinson's disorder – which manifests specific brain abnormalities including basal ganglia dysfunction and dopamine reduction — and visual anomalies. Collectively, it was observed that context integration remains intact in Parkinson’s disorder, suggesting that basal ganglia and dopamine (which are compromised in this condition) are not linked to VI susceptibility. Collectively, the discoveries in this thesis hold profound implications for advancing our understanding of context integration, pictorial depth perception, and the broader field of VI research. Firstly, it urges future research to consider the methodology in use, and its implications for the obtained findings. Furthermore, findings regarding susceptibility trends ought to be revisited, as context integration and pictorial depth perception are likely to develop before the age of seven years. Finally, the findings concerning reduced susceptibility to VIs amongst experts in medical image interpretation suggest that alongside changes in top-down perception, the training and expertise of radiologists and radiographers also lead to changes in bottom-up perception – as manifested by their reduced VIs susceptibility.

M3 - Doctoral Thesis

PB - Lancaster University

ER -