Paola Bressan

University of Padova | UNIPD · Department of General Psychology

Early exposure to parental features shapes later sexual preferences in fish, birds, and mammals. Here I report that human males’ preferences for a conspicuous trait, colourful eyes, are affected by the eye colour of mothers. Female faces with light (blue or green) eyes were liked better by men whose mother had light eyes; the effect broke down in t...

We animals have evolved a variety of mechanisms to avoid conspecifics who might be infected. It is currently unclear whether and why this "behavioral immune system" targets unfamiliar individuals more than familiar ones. Here I answer this question in humans, using publicly available data of a recent study on 1969 participants from India and 1615 f...

We social animals must balance the need to avoid infections with the need to interact with conspecifics. To that end we have evolved, alongside our physiological immune system, a suite of behaviors devised to deal with potentially contagious individuals. Focusing mostly on humans, the current review describes the design and biological innards of th...

Visual illusions have been studied extensively, but their time course has not. Here we show, in a sample of more than 550 people, that unrestricted presentation times—as opposed to presentations lasting only a single second—weaken the Ebbinghaus illusion, strengthen lightness contrast with double increments, and do not alter lightness contrast with...

Men with light eyes lack the dominant gene allele that codes for dark-brown eyes. Pairing with a woman who lacks the same allele must increase paternity confidence in these men, because any children with dark eyes would be extremely unlikely to have been fathered by them. This notion implies that men with light (blue or green) eyes should (1) prefe...

Here I report that, when partnered people judge the facial attractiveness of potential mates for a short-and a long-term relationship, the order in which the two conditions are presented biases responses in a systematic manner. Women and men display symmetrical biases. Women find men less attractive as new long-term partners if they have first imag...

In the phase between ovulation and potential implantation of the egg, and especially during pregnancy, females downregulate their immune system to prevent it from attacking the (future) embryo, which is after all a half-foreign organism. Yet this adaptive mechanism, that is set off by rising progesterone, makes females more vulnerable to pathogens...

This paper presents a broad perspective on how mental disease relates to the different evolutionary strategies of men and women and to growth, metabolism, and mitochondria—the enslaved bacteria in our cells that enable it all. Several mental disorders strike one sex more than the other; yet what truly matters, regardless of one’s sex, is how much o...

In the phase between ovulation and potential implantation of the egg, and especially during pregnancy, females downregulate their immune system to prevent it from attacking the (future) embryo, which is after all a half-foreign organism. Yet this adaptive mechanism, that is set off by rising progesterone, makes females more vulnerable to pathogens...

Visual illusions do not just help uncover how people perceive reality but are also used to investigate cognitive styles, cultural differences, and mental disorders like autism or schizophrenia. Participants are often free to inspect the illusions, and some take longer than others to do so. Here we show, for the first time, that spontaneous inspecti...

Reproducibility is essential to science, yet a distressingly large number of research findings do not seem to replicate. Here I discuss one underappreciated reason for this state of affairs. I make my case by noting that, due to artifacts, several of the replication failures of the vastly advertised Open Science Collaboration’s Reproducibility Proj...

Tucked inside our cells, we animals (and plants, and fungi) carry mitochondria, minuscule descendants of bacteria that invaded our common ancestor 2 billion years ago. This unplanned breakthrough endowed our ancestors with a convenient, portable source of energy, enabling them to progress towards more ambitious forms of life. Mitochondria still man...

Tucked inside our cells, we animals (and plants, and fungi) carry mitochondria, minuscule descendants of bacteria that invaded our common ancestor two billion years ago. This unplanned breakthrough endowed our ancestors with a convenient, portable source of energy, enabling them to progress towards more ambitious forms of life. Mitochondria still m...

People with superior mathematical abilities turn out to have an autism spectrum disorder more often than others do. The empathising-systemising theory proposes that this link is mediated by these individuals’ stronger tendency to systemise (detect patterns, derive rules), along with the fact that mathematics is the perfect example of a rule-based,...

Interactions between the ways we process space, numbers and time may arise from shared and innate generic magnitude representations. Alternatively or concurrently, such interactions could be due to the use of physical magnitudes, like spatial extent, as metaphors for more abstract ones, like number and duration. That numbers might be spatially repr...

In several species, mate choice is influenced by parental features through sexual imprinting, but in humans evidence is scarce and open to alternative explanations. We examined whether daughters' preference for mates with light vs dark eyes is affected by the eye colour of parents. In an online study, over one thousand women rated the attractivenes...

Most of the energy we get to spend is furnished by mitochondria, minuscule living structures sitting inside our cells or dispatched back and forth within them to where they are needed. Mitochondria produce energy by burning down what remains of our meal after we have digested it, but at the cost of constantly corroding themselves and us. Here we re...

Psychologists and psychiatrists tend to be little aware that (a) microbes in our brains and guts are capable of altering our behavior; (b) viral DNA that was incorporated into our DNA millions of years ago is implicated in mental disorders; (c) many of us carry the cells of another human in our brains; and (d) under the regulation of viruslike elem...

L'aspetto dei nostri occhi è influenzato dalle emozioni che proviamo, ma...

Una pecora è in grado di ricordare i musi di cinquanta sue diverse colleghe per anni...

Un singolo starnuto è in grado di produrre un milione di goccioline infette, che scendono verso il suolo a una velocità inferiore a un centimetro al minuto

I colori sono in grado di alterare nettamente il sapore di cibi e bevande...

Le mattonelle blu sono in realtà identiche a quelle gialle: sono tutte fisicamente grigie...

Perhaps because gastroenterology, immunology, toxicology, and the nutrition and agricultural sciences are outside of their competence and responsibility, psychologists and psychiatrists typically fail to appreciate the impact that food can have on their patients’ condition. Here we attempt to help correct this situation by reviewing, in non-technic...

Psychologists and psychiatrists tend to be little aware that (a) microbes in our brains and guts are capable of altering our behavior; (b) viral DNA that was incorporated into our DNA millions of years ago is implicated in mental disorders; (c) many of us carry the cells of another human in our brains; and (d) under the regulation of viruslike elem...

Natural selection has favored the evolution of behaviors that benefit not only one's genes, but also their copies in genetically related individuals. These behaviors include optimal outbreeding (choosing a mate that is neither too closely related, nor too distant), nepotism (helping kin), and spite (hurting non-kin at a personal cost), and all requ...

A target gray spot looks darker on a white background than on a black one: the contrast illusion. If the target is embedded in a context consisting of black spots on the white background and white spots on the black background, the effect reverses: the dungeon illusion. Whether the dungeon figure produces contrast or contrast reversal depends on wh...

When we move, the flat projection of the three-­‐dimensional world onto our retinae changes; these changes alone can induce a powerful sensation of depth. The effectiveness of this process is well illustrated by the stereokinetic effect and the kinetic depth effect (or structure from motion), which refer to illusions of depth induced by moving two-...

Background / Purpose: To investigate the reversal of direction that occurs in the Poggendorff illusion when the diagonal is formed by subjective contours. We assess directly where the diagonal appears to intersect the rectangle, by asking subjects to mark the relevant spot(s). Main conclusion: For the acute angle edge of the diagonal there is...

In the Ebbinghaus illusion, a circle surrounded by smaller circles is perceived as larger than an identical one surrounded by larger circles. The illusion is reportedly weaker in individuals with (disorganized) schizophrenia or schizotypy than in controls, a finding that has been interpreted as evidence that both schizophrenia and schizotypy involv...

Background / Purpose: To illuminate the origin of the Poggendorff illusion and its reversal with subjective contour diagonals by defining all the contours by line-endings rather than interpolation between pacmen. Main conclusion: The illusion is in the normal direction, although weaker than with real contours. Second-order contours defined by...

During central fixation, a moving pattern of nontargets induces repeated temporary blindness to even salient peripheral targets: motion-induced blindness (MIB). Hitherto, behavioral measures of MIB have relied on subjective judgments. Here, we offer an objective alternative that builds on earlier findings regarding the effects of MIB on the detecta...

Even after they have taken all reasonable measures to decrease the probability that their spouses cheat on them, men still face paternal uncertainty. Such uncertainty can lead to paternal disinvestment, which reduces the children's probability to survive and reproduce, and thus the reproductive success of the fathers themselves. A theoretical model...

Performing mental subtractions affects time (duration) estimates, and making time estimates disrupts mental subtractions. This interaction has been attributed to the concurrent involvement of time estimation and arithmetic with general intelligence and working memory. Given the extant evidence of a relationship between time and number, here we test...

Background / Purpose: The Poggendorff illusion is a puzzle. Numerous mechanisms have been proposed to account for it, including angle expansion caused by lateral inhibition in the visual cortex, spatial blurring, assimilation to cardinal axes, apparent depth induction, distance mis-estimation and extrapolation errors. Several such factors may be...

Von Hippel & Trivers (VH&T) interpret belief in God and belief in strong government as the outcome of an active process of self-deception on a worldwide scale. We propose, instead, that these beliefs might simply be a passive spin-off of efficient cognitive processes.

Human beings are among the species with the best color perception of all mammals. yet, transparency can be perceived in scenes in which color cues point to opacity. Why do we ignore such color cues? Here we argue that colors, rather than being passively registered, must be actively recreated and then bound to other stimulus attributes. In this proc...

The visual system's computation of lightness (perceived reflectance) leads to contrast effects in which a gray target region appears lighter on a black background than on a white one. Here we show a paradoxical contrast effect in which targets look lighter after adding regions that increase the scene's average luminance, and darker after adding reg...

The target paper reviewed in this article was titled "Transparency: relation to depth, subjective contours, luminance, and neon colour spreading" coauthored by K Nakayama, S Shimojo, and V S Ramachandran, published in 1990. This paper, one of the first in a series on surface perception, examined how in untextured stereograms, local disparity and lu...

Inclusive fitness theory predicts that organisms will tend to help close kin more than less related individuals. In a variety of birds and mammals, relatives are recognized by comparing their phenotype to an internal representation or template, which might be learned through either repeated exposure to family members or self-inspection. Mirrors are...

We studied altruistic behaviors of varying biological cost (high, medium, and low) among siblings of varying genetic relatedness (full, half, and step). In agreement with inclusive fitness theory, the relative importance of either reliable (such as co-residence) or heuristic (such as emotional closeness) kinship cues depended crucially on the costs...

Here we show that the automatic, involuntary process of attentional capture is predictive of beliefs that are typically considered as much more complex and higher-level. Whereas some beliefs are well supported by evidence, others, such as the belief that coincidences occur for a reason, are not. We argue that the tendency to assign meaning to coinc...

Are men more likely than women to take into account a child's facial resemblance to themselves when making hypothetical parental investment choices? The benefits of self-resemblance in decreasing relatedness uncertainty are larger in men than in women for direct descendants. However, they are identical in men and women for collateral relatives, suc...

Because men of higher genetic quality tend to be poorer partners and parents than men of lower genetic quality, women may profit from securing a stable investment from the latter, while obtaining good genes via extrapair mating with the former. Only if conception occurs, however, do the evolutionary benefits of such a strategy overcome its costs. A...

When engaged in a visual task, we can fail to detect unexpected events that would otherwise be very noticeable. Here we ask whether a common auditory task, such as that of attending to a verbal stream, can also make us blind to the presence of visual objects that we do not anticipate. In two experiments, one hundred and twenty observers watched a d...

In various versions of the dungeon illusion (P. Bressan, 2001), we show that grouping between targets and contextual disks determines whether remote luminances affect target lightness or not. In the dungeon illusion, target disks surrounded by contextual disks contrast with them rather than with the immediate background. We formally establish the e...

When our attention is engaged in a visual task, we can be blind to events which would otherwise not be missed. In three experiments, 97 out of the 165 observers performing a visual attention task failed to notice an unexpected, irrelevant object moving across the display. Surprisingly, this object significantly lowered accuracy in the primary task...

Replies to comments mad by Howe et al. on the current author's original article. The double-anchoring theory of lightness (P. Bressan, 2006b) assumes that any given region belongs to a set of frameworks, created by Gestalt grouping principles, and receives a provisional lightness within each of them; the region's final lightness is a weighted avera...

Provides a postscript to the comments made by Howe et al., which were in response to the current author's reply to previous comments on the current author's original article. In their postscript, Howe et al. raise six new miscellaneous points. In the current paper, Bressan addresses each of these new points in turn, and presents and defends her poi...

È opinione comune che il mondo appaia come lo vediamo semplicemente perché è così. Al contrario, la realtà che ci sta davanti è, per intero, una costruzione del nostro cervello. In pagine sorprendenti e curiose, Paola Bressan svela i complessi fondamenti scientifici dei piccoli misteri che costellano la nostra vita quotidiana. Scopriremo come costr...

The specific gray shades in a visual scene can be derived from relative luminance values only when an anchoring rule is followed. The double-anchoring theory I propose in this article, as a development of the anchoring theory of Gilchrist et al. (1999), assumes that any given region (a) belongs to one or more frameworks, created by Gestalt grouping...

The empirical question of whether or not the lightness of a region is accounted for purely by the average luminance of its surround has a complex answer that depends on whether such a region is an increment, a decrement, or intermediate relative to the luminances of the contiguous surfaces. It is shown here that a new model of lightness, based on a...

Simultaneous lightness contrast is stronger when the dark and light backgrounds of the classic display (where one of the targets is an increment and the other is a decrement) are replaced by articulated fields of equivalent average luminances. Although routinely attributed to articulation per se, this effect may simply result from the increase in h...

Sivaprasad and Saleh seem to suggest that we misperceive the moon as white because contemplation of the skies is not what we evolved for. The latter claim is true, of course. For example, the sun and the moon look much the same size to us; yet the sun is 400 times as far away and 400 times as large as the moon, and by the rules of size constancy sh...

Do infants look more like their fathers or their mothers? The available data are contradictory, but were collected through different procedures: either by asking judges to identify the parent in a triplet of adults (straight guess) or by asking them to rate resemblance on a scale and then recoding highest ratings to parents as correct guesses (gues...

Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We recreated all the known types of anti-...

Neon colour spreading occurs when sections of a lattice are replaced by segments of a different colour. This colour appears to diffuse out of the segments, and produce a slightly tinted transparent surface floating above the lattice. In two of the four experiments reported here, observers varied the colour of an area in a test display, until it mat...

Shadow-compatibility of simultaneous lightness contrast is discussed by Alexander D Logvinenko and Paola Bressan, with examples claiming to provide a test of the hypothesis.

People hardly ever realize that their belief in their high rate of success in detecting family resemblances is affected by their knowledge of the actual genetic link between individuals. In the three studies reported here, 100 men and 100 women were requested to estimate the facial resemblance of photographically portrayed child-adult pairs, while...

The Ebbinghaus illusion has traditionally been considered as either a sensory or a cognitive illusion, or some combination of these two. Cognitive contrast explanations take support from the way the illusion varies with the degree of shape similarity between the test and inducing elements; we show, however, that contour interaction explanations may...

It has been suggested that in a socially monogamous system where fathers invest in their mate's offspring but paternity is far from certain, it will be adaptive on the part of infants to conceal their father's identity; but the opposite claim has also been made that this is against the genetic interests of the fathers, and a high frequency of adult...

This paper argues against the theory that people interpret unusual coincidences as paranormal because they misunderstand the probability of their occurring by chance. In the two studies reported here, 214 subjects were given a questionnaire on the frequency of coincidences in their lives, a series of probabilistic problems, and a scale assessing th...

Grey looks darker when set against white than when set against black. In some complex figures this illusion becomes startling, and can be shown to depend on the perceptual organisation of regions within the image. The most widely accepted explanations of such effects are based on the analysis of the junctions formed where the boundaries of nearby r...

In this paper we demonstrate the existence of simultaneous lightness contrast in displays in which the target patches are both more luminant than their surrounds. These effects are not predicted by theories of lightness that assume that the highest luminance in a scene is perceived as white, and anchors all the other luminances. We show that the st...

A grey patch set against a dark background looks lighter than an identical grey patch set against a light background. Typically, the grey of the patches is more luminant than the dark background, and less luminant than the light background. A weaker effect also obtains when the two target greys are both less luminant than their backgrounds. Yet, no...

This paper is about a phenomenon that combines a delicate beauty with a profound significance for understanding visual perception. The neon-like glow of a color that escapes the boundaries of a real figure and fills the surrounding area until it is halted by the boundaries of an illusory figure has an ethereal quality unlike any other brightness an...

Guest editorial ---- The papers in this special issue tell an elusive story. No plot might be discerned at first; no emergent structure beyond a plain sequence of interesting facts. Yet there is a moment, possibly halfway through the story, when a revelation occurs and a filigree of obvious connections comes into existence. It is at this point tha...

Ejima, Redies, Takahashi and Akita [(1984) Vision Research, 24, 1719-1726], studying the dependence of the neon colour spreading effect on wavelength and illuminance, found a number of relationships that appeared of difficult interpretation. This paper shows that these relationships can all be logically predicted within Grossberg and Mingolla's [(1...

A previously unreported motion illusion is described. Oblique lines that drift smoothly on the retina in a vertical direction appear to be displaced laterally. The effect occurs both for moving lines under fixation and for stationary lines under ocular tracking of an external target. Orientation, length, and homogeneity of the obliques affect the m...

Overlapping figures can produce consistent depth stratification even when chromatically homogeneous. Since neither T-junctions nor X-junctions are present in these patterns, the problem arises of what rules determine the direction of depth stratification, ie which surfaces appear in front and which behind. In a series of demonstrations and formal e...

Stereo capture occurs when a regular pattern of repeating elements with zero disparity is superimposed on a disparate subjective figure. The elements enclosed within the subjective contours, but not those outside them, are perceptually captured and pulled on the same depth plane of the disparate figure. The phenomenon has been interpreted as the re...

The phenomenon of "motion capture" has been demonstrated by presenting, one after the other, two identical Kanizsa squares spatially separated and superimposed on a regular matrix of dots. For appropriate temporal intervals, one illusory square is seen to jump from one location to the other and the dots in it appear to move with it even though they...

This paper develops the idea (Bressan, 1993) that neon spreading derives from the perceptual scissioning of ordinary assimilation color, a process identical to that occurring with nonillusory colors in phenomenal transparency. It is commonly held that the critical elements in achromatic neon spreading patterns must be of luminance intermediate betw...

When a plaid pattern composed of a stationary vertical grating and a horizontally drifting diagonal grating is shown behind a circular aperture, the pattern appears to move coherently in a vertical direction. When the bars of the stationary grating are narrower than those of the moving grating, only the latter is seen to move, in a direction orthog...

Neon colour spreading has been shown to disappear if certain figural conditions are not met. Evidence is presented which suggests that these conditions are only incidentally related to the neon spreading effect; in particular, that they can be violated as long as the structure remains compatible with the interpretation of a transparent surface. It...

The perceptual outcome and the motion-aftereffect duration generated by the rotation on the frontal plane of an ellipse with a bar depend on whether the bar is placed along the major or the minor axis. When the bar is placed along the minor axis, a stereokinetic transformation occurs, and the pattern looks like a tilting ring with a perpendicular b...

It has so far been assumed that velocity contrast effects can be explained by local lateral inhibition processes which act to enhance the difference in velocity between a target and its immediate surround. A new velocity illusion is here reported that seriously questions this notion.

If a pattern of concentric circles, interrupted so as to produce the perception of a subjective bar extending from the centre to the periphery of the pattern, was slowly rotated in a plane perpendicular to the line of sight, observers reported seeing the bar slanted in depth and moving over complete and stationary concentric circles. When the inter...

Recent work (Shimojo, Silverman & Nakayama, 1989; Vision Research, 29, 619-626) suggests that the visual system must discriminate between extrinsic boundaries (boundaries created by front occluding surfaces) and intrinsic boundaries (real object boundaries) in order to recognize objects and that this would importantly affect the way it solves the s...

The research described in the present article was designed to identify the minimal conditions for the visual perception of 3-dimensional structure from motion by comparing the theoretical limitations of ideal observers with the perceptual performance of actual human subjects on a variety of psychophysical tasks. The research began with a mathematic...

The research described in the present article was designed to identify the minimal conditions for the visual perception of 3-dimensional structure from motion by comparing the theoretical limitations of ideal observers with the perceptual performance of actual human subjects on a variety of psychophysical tasks. The research began with a mathematic...

A new illusory effect is described which consists of a conspicuous perceptual overestimation of the speed at which a wheel rolling across an observer's visual field appears to be rotating. Wheels appear to revolve much faster than is compatible with their linear displacement. Experimental verification of the genuineness and magnitude of the effect...