Marco Bertamini | University of Liverpool (original) (raw)
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Papers by Marco Bertamini
Perception, Apr 15, 2024
Vittorio Benussi (1878–1927) is known for numerous studies on optical illusions, visual and hapti... more Vittorio Benussi (1878–1927) is known for numerous studies on optical illusions, visual and haptic perception, spatial and time perception. In Padova, he had a brilliant student who carefully worked on the topic of how people estimate numerosity, Silvia De Marchi (1897–1936). Her writings have never been translated into English before. Here we comment on her work and life, characterized also by the challenges faced by women in academia. The studies on perception of numerosity from her thesis were published as an article in 1929. We provide a translation from Italian, a redrawing of its 23 illustrations and of the graphs. It shows an original experimental approach and an anticipation of what later became known as magnitude estimation.
Perception, 2004
We used holes to study unilateral border ownership and in particular the information carried by t... more We used holes to study unilateral border ownership and in particular the information carried by the sign of the curvature along the contour (ie the difference between convex and concave regions). When people perceive a hole, its shape has a reversed curvature polarity (ie a changed sign of curvature) compared to the same region perceived as an object. Bertamini (2001 Perception30 1295–1310), and Bertamini and Croucher (2003 Cognition87 33–54) suggested and found evidence to support the hypothesis that, because convex regions are perceived as parts, positional information is more readily available for convex regions. Therefore a change is predicted when a given region is perceived as either a hole or a figure. We confirm that finding in this study, using holes defined by binocular disparity. We conclude that a change from figure to hole always reverses the encoding of curvature polarity. In turn, polarity obligatorily affects perceived part structure and the processing of position.
A number of studies have explored visual symmetry processing by measuring 16 event related potent... more A number of studies have explored visual symmetry processing by measuring 16 event related potentials and neural oscillatory activity. There is a sustained posterior 17 negativity (SPN) related to the presence of symmetry. There is also functional MRI activity 18 in extrastriate visual areas and in the lateral occipital complex. We summarise the evidence 19 by answering six questions. (1) Is there an automatic and sustained response to symmetry 20 in visual areas? Answer: Yes, and this suggests automatic processing of symmetry. (2) 21 Which brain areas are involved in symmetry perception? Answer: There is an extended 22 network from extrastriate areas to higher areas. (3) Is reflection special? Answer: 23 Reflection is the optimal stimulus for a more general regularity-sensitive network. (4) Is 24 the response to symmetry independent of view angle? Answer: When people classify 25 patterns as symmetrical or random, the response to symmetry is view-invariant. When 26 people attend to ...
Journal of Cognitive Neuroscience, 2019
The brain can organize elements into perceptually meaningful gestalts. Visual symmetry is a usefu... more The brain can organize elements into perceptually meaningful gestalts. Visual symmetry is a useful tool to study gestalt formation, and we know that there are symmetry-sensitive regions in the extrastriate cortex. However, it is unclear whether symmetrical gestalt formation happens automatically, whatever the participant's current task is. Does the visual brain always organize and interpret the retinal image when possible, or only when necessary? To test this, we recorded an ERP called the sustained posterior negativity (SPN). SPN amplitude increases with the proportion of symmetry in symmetry + noise displays. We compared the SPN across five tasks with different cognitive and perceptual demands. Contrary to our predictions, the SPN was the same across four of the five tasks but selectively enhanced during active regularity discrimination. Furthermore, during regularity discrimination, the SPN was present on hit trials and false alarm trials but absent on miss and correct reject...
Annals of the New York Academy of Sciences, 2018
Symmetry is an important and prominent feature of the visual world. It has been studied as a basi... more Symmetry is an important and prominent feature of the visual world. It has been studied as a basis for image segmentation and perceptual organization, but it also plays a role in higher level processes, such as face and object perception. Over the past decade, there has been progress in the study of the neural mechanisms of symmetry perception in humans and other animals. There is extended activity in the ventral stream, including the lateral occipital complex (LOC) and VO1; this activity starts in V3 and it occurs independently of the task (automatic response). Additionally, when the task requires processing of symmetry, the activation may emerge for objects that are symmetrical, even though they do not project a symmetrical image. There is also some evidence of hemispheric lateralization, especially for the LOC. We review the studies on the cortical basis of visual symmetry processing and its links to encoding of other aspects of the visual world, such as faces and objects.
Quarterly journal of experimental psychology (2006), Jan 12, 2017
The term 'Perceptual goodness' refers to the strength, obviousness or salience of a visua... more The term 'Perceptual goodness' refers to the strength, obviousness or salience of a visual configuration. Recent work has found strong agreement between theoretical, neural and behavioural measures of perceptual goodness across a wide range of different symmetrical visual patterns (Makin et al. 2016). We used these pattern types again to explore the relationship between perceptual goodness and aesthetic preference. A group of 50 UK participants rated the patterns on a 0-100 scale. Preference ratings positively correlated with four overlapping measures of perceptual goodness. We then replicated this finding in Egypt, suggesting that our results reflect universal aspects of human preference. The third experiment provided consistent results with a different stimulus set. We conclude that symmetry is an aesthetic primitive that is attractive because of the way it is processed by the visual system.
i-Perception
Previous research has shown that explicit emotional content or physical image properties (e.g., l... more Previous research has shown that explicit emotional content or physical image properties (e.g., luminance, size, and numerosity) alter subjective duration. Palumbo recently demonstrated that the presence or absence of abstract reflectional symmetry also influenced subjective duration. Here, we explored this phenomenon further by varying the type of symmetry (reflection or rotation) and the objective duration of stimulus presentation (less or more than 1 second). Experiment 1 used a verbal estimation task in which participants estimated the presentation duration of reflection, rotation symmetry, or random square-field patterns. Longer estimates were given for reflectional symmetry images than rotation or random, but only when the image was presented for less than 1 second. There was no difference between rotation and random. These findings were confirmed by a second experiment using a paired-comparison task. This temporal distortion could be because reflection has positive valence or...
i-Perception
We present a series of patterns, in which texture is perceived differently at fixation in compari... more We present a series of patterns, in which texture is perceived differently at fixation in comparison to the periphery, such that a physically uniform stimulus yields a nonuniform percept. We call this the Honeycomb illusion, and we discuss it in relation to the similar Extinction illusion (Ninio & Stevens, 2000). The effect remains strong despite multiple fixations, dynamic changes, and manipulations of the size of texture elements. We discuss the phenomenon in relation to how vision achieves a detailed and stable representation of the environment despite changes in retinal spatial resolution and dramatic changes across saccades. The Honeycomb illusion complements previous related observations in suggesting that this representation is not necessarily based on multiple fixations (i.e., memory) or on extrapolation from information available to central vision.
i-Perception, 2016
Empirical work has shown that people like visual symmetry. We used a gaze-driven evolutionary alg... more Empirical work has shown that people like visual symmetry. We used a gaze-driven evolutionary algorithm technique to answer three questions about symmetry preference. First, do people automatically evaluate symmetry without explicit instruction? Second, is perfect symmetry the best stimulus, or do people prefer a degree of imperfection? Third, does initial preference for symmetry diminish after familiarity sets in? Stimuli were generated as phenotypes from an algorithmic genotype, with genes for symmetry (coded as deviation from a symmetrical template, deviation-symmetry, DS gene) and orientation (0° to 90°, orientation, ORI gene). An eye tracker identified phenotypes that were good at attracting and retaining the gaze of the observer. Resulting fitness scores determined the genotypes that passed to the next generation. We recorded changes to the distribution of DS and ORI genes over 20 generations. When participants looked for symmetry, there was an increase in high-symmetry genes....
Vision research, Jan 13, 2015
Neuroimaging work has shown that visual symmetry activates extrastriate brain areas, most consist... more Neuroimaging work has shown that visual symmetry activates extrastriate brain areas, most consistently the lateral occipital complex (LOC). LOC activation increases with proportion of symmetrical dots (pSymm) in a degraded display. In the current work, we recorded a posterior ERP called the sustained posterior negativity (SPN), which is relatively negative for symmetrical compared to random patterns. We predicted that SPN would also scale with pSymm, because it is probably generated by the LOC. Twenty-four participants viewed dot patterns with different levels of regularity: 0% regularity (full random configuration) 20%, 40% 60%, 80%, 100% (full reflection symmetry). Participants judged if the pattern contained "some regularity" or "no regularity". As expected, the SPN amplitude increased with pSymm, while the latency and duration was the same in all conditions. The SPN was independent of the participant's decision, and it was present on some trials where peo...
Perception, Apr 15, 2024
Vittorio Benussi (1878–1927) is known for numerous studies on optical illusions, visual and hapti... more Vittorio Benussi (1878–1927) is known for numerous studies on optical illusions, visual and haptic perception, spatial and time perception. In Padova, he had a brilliant student who carefully worked on the topic of how people estimate numerosity, Silvia De Marchi (1897–1936). Her writings have never been translated into English before. Here we comment on her work and life, characterized also by the challenges faced by women in academia. The studies on perception of numerosity from her thesis were published as an article in 1929. We provide a translation from Italian, a redrawing of its 23 illustrations and of the graphs. It shows an original experimental approach and an anticipation of what later became known as magnitude estimation.
Perception, 2004
We used holes to study unilateral border ownership and in particular the information carried by t... more We used holes to study unilateral border ownership and in particular the information carried by the sign of the curvature along the contour (ie the difference between convex and concave regions). When people perceive a hole, its shape has a reversed curvature polarity (ie a changed sign of curvature) compared to the same region perceived as an object. Bertamini (2001 Perception30 1295–1310), and Bertamini and Croucher (2003 Cognition87 33–54) suggested and found evidence to support the hypothesis that, because convex regions are perceived as parts, positional information is more readily available for convex regions. Therefore a change is predicted when a given region is perceived as either a hole or a figure. We confirm that finding in this study, using holes defined by binocular disparity. We conclude that a change from figure to hole always reverses the encoding of curvature polarity. In turn, polarity obligatorily affects perceived part structure and the processing of position.
A number of studies have explored visual symmetry processing by measuring 16 event related potent... more A number of studies have explored visual symmetry processing by measuring 16 event related potentials and neural oscillatory activity. There is a sustained posterior 17 negativity (SPN) related to the presence of symmetry. There is also functional MRI activity 18 in extrastriate visual areas and in the lateral occipital complex. We summarise the evidence 19 by answering six questions. (1) Is there an automatic and sustained response to symmetry 20 in visual areas? Answer: Yes, and this suggests automatic processing of symmetry. (2) 21 Which brain areas are involved in symmetry perception? Answer: There is an extended 22 network from extrastriate areas to higher areas. (3) Is reflection special? Answer: 23 Reflection is the optimal stimulus for a more general regularity-sensitive network. (4) Is 24 the response to symmetry independent of view angle? Answer: When people classify 25 patterns as symmetrical or random, the response to symmetry is view-invariant. When 26 people attend to ...
Journal of Cognitive Neuroscience, 2019
The brain can organize elements into perceptually meaningful gestalts. Visual symmetry is a usefu... more The brain can organize elements into perceptually meaningful gestalts. Visual symmetry is a useful tool to study gestalt formation, and we know that there are symmetry-sensitive regions in the extrastriate cortex. However, it is unclear whether symmetrical gestalt formation happens automatically, whatever the participant's current task is. Does the visual brain always organize and interpret the retinal image when possible, or only when necessary? To test this, we recorded an ERP called the sustained posterior negativity (SPN). SPN amplitude increases with the proportion of symmetry in symmetry + noise displays. We compared the SPN across five tasks with different cognitive and perceptual demands. Contrary to our predictions, the SPN was the same across four of the five tasks but selectively enhanced during active regularity discrimination. Furthermore, during regularity discrimination, the SPN was present on hit trials and false alarm trials but absent on miss and correct reject...
Annals of the New York Academy of Sciences, 2018
Symmetry is an important and prominent feature of the visual world. It has been studied as a basi... more Symmetry is an important and prominent feature of the visual world. It has been studied as a basis for image segmentation and perceptual organization, but it also plays a role in higher level processes, such as face and object perception. Over the past decade, there has been progress in the study of the neural mechanisms of symmetry perception in humans and other animals. There is extended activity in the ventral stream, including the lateral occipital complex (LOC) and VO1; this activity starts in V3 and it occurs independently of the task (automatic response). Additionally, when the task requires processing of symmetry, the activation may emerge for objects that are symmetrical, even though they do not project a symmetrical image. There is also some evidence of hemispheric lateralization, especially for the LOC. We review the studies on the cortical basis of visual symmetry processing and its links to encoding of other aspects of the visual world, such as faces and objects.
Quarterly journal of experimental psychology (2006), Jan 12, 2017
The term 'Perceptual goodness' refers to the strength, obviousness or salience of a visua... more The term 'Perceptual goodness' refers to the strength, obviousness or salience of a visual configuration. Recent work has found strong agreement between theoretical, neural and behavioural measures of perceptual goodness across a wide range of different symmetrical visual patterns (Makin et al. 2016). We used these pattern types again to explore the relationship between perceptual goodness and aesthetic preference. A group of 50 UK participants rated the patterns on a 0-100 scale. Preference ratings positively correlated with four overlapping measures of perceptual goodness. We then replicated this finding in Egypt, suggesting that our results reflect universal aspects of human preference. The third experiment provided consistent results with a different stimulus set. We conclude that symmetry is an aesthetic primitive that is attractive because of the way it is processed by the visual system.
i-Perception
Previous research has shown that explicit emotional content or physical image properties (e.g., l... more Previous research has shown that explicit emotional content or physical image properties (e.g., luminance, size, and numerosity) alter subjective duration. Palumbo recently demonstrated that the presence or absence of abstract reflectional symmetry also influenced subjective duration. Here, we explored this phenomenon further by varying the type of symmetry (reflection or rotation) and the objective duration of stimulus presentation (less or more than 1 second). Experiment 1 used a verbal estimation task in which participants estimated the presentation duration of reflection, rotation symmetry, or random square-field patterns. Longer estimates were given for reflectional symmetry images than rotation or random, but only when the image was presented for less than 1 second. There was no difference between rotation and random. These findings were confirmed by a second experiment using a paired-comparison task. This temporal distortion could be because reflection has positive valence or...
i-Perception
We present a series of patterns, in which texture is perceived differently at fixation in compari... more We present a series of patterns, in which texture is perceived differently at fixation in comparison to the periphery, such that a physically uniform stimulus yields a nonuniform percept. We call this the Honeycomb illusion, and we discuss it in relation to the similar Extinction illusion (Ninio & Stevens, 2000). The effect remains strong despite multiple fixations, dynamic changes, and manipulations of the size of texture elements. We discuss the phenomenon in relation to how vision achieves a detailed and stable representation of the environment despite changes in retinal spatial resolution and dramatic changes across saccades. The Honeycomb illusion complements previous related observations in suggesting that this representation is not necessarily based on multiple fixations (i.e., memory) or on extrapolation from information available to central vision.
i-Perception, 2016
Empirical work has shown that people like visual symmetry. We used a gaze-driven evolutionary alg... more Empirical work has shown that people like visual symmetry. We used a gaze-driven evolutionary algorithm technique to answer three questions about symmetry preference. First, do people automatically evaluate symmetry without explicit instruction? Second, is perfect symmetry the best stimulus, or do people prefer a degree of imperfection? Third, does initial preference for symmetry diminish after familiarity sets in? Stimuli were generated as phenotypes from an algorithmic genotype, with genes for symmetry (coded as deviation from a symmetrical template, deviation-symmetry, DS gene) and orientation (0° to 90°, orientation, ORI gene). An eye tracker identified phenotypes that were good at attracting and retaining the gaze of the observer. Resulting fitness scores determined the genotypes that passed to the next generation. We recorded changes to the distribution of DS and ORI genes over 20 generations. When participants looked for symmetry, there was an increase in high-symmetry genes....
Vision research, Jan 13, 2015
Neuroimaging work has shown that visual symmetry activates extrastriate brain areas, most consist... more Neuroimaging work has shown that visual symmetry activates extrastriate brain areas, most consistently the lateral occipital complex (LOC). LOC activation increases with proportion of symmetrical dots (pSymm) in a degraded display. In the current work, we recorded a posterior ERP called the sustained posterior negativity (SPN), which is relatively negative for symmetrical compared to random patterns. We predicted that SPN would also scale with pSymm, because it is probably generated by the LOC. Twenty-four participants viewed dot patterns with different levels of regularity: 0% regularity (full random configuration) 20%, 40% 60%, 80%, 100% (full reflection symmetry). Participants judged if the pattern contained "some regularity" or "no regularity". As expected, the SPN amplitude increased with pSymm, while the latency and duration was the same in all conditions. The SPN was independent of the participant's decision, and it was present on some trials where peo...