What does gender has to do with math? Complex questions require complex answers.

Whether mathematics is a gendered domain or not is a long-lasting issue bringing along major social and educational implications. The females' underrepresentation in science, technology, engineering, and mathematics (STEM) has been considered one of the key signs of the math gender gap, although the current view largely attributes the origin of this phenomenon to sociocultural factors. Indeed, recent approaches to math gender differences reached the universal conclusion that nature and nurture exert reciprocal effects on each other, establishing the need for approaching the study of the math gender issue only once its intrinsic complexity has been accepted. Building upon a flourishing literature, this review provides an updated synthesis of the evidence for math gender equality at the start, and for math gender inequality on the go, challenging the role of biological factors. In particular, by combining recent findings from different research areas, the paper discusses the persistence of the "math male myth" and the associated "female are not good at math myth," drawing attention to the complex interplay of social and cultural forces that support such stereotypes. The suggestion is made that longevity of these myths results from the additive effects of two independent cognitive biases associated with gender stereotypes and with math stereotypes, respectively. Scholars' responsibility in amplifying these myths by pursuing some catching lines of research is also discussed.

Non-symbolic numerosity encoding escapes spatial frequency equalization.

The exact visual mechanisms underpinning the approximate number system are still debated. Recent evidence suggests that numerosity is extracted on segmented visual objects, at least for a moderate numerical range (e.g., < 100 items), whereas alternative models rather propose that numerosity is derived from low-level features (e.g., power spectrum) of an unsegmented image, independently from the range. Here, to disentangle these accounts, we generated stimuli that were equalized for spatial frequency amplitude spectrum and luminance across sets of moderate range numerosities (e.g., 9-15 dots), while independently manipulating the perceived item segmentation by connecting dots with illusory contours (ICs). In Experiment 1, participants performed a numerical discrimination task, in which they had to select the numerically larger between two stimuli: a reference stimulus (always 12 dots) and a test stimulus (from 9 to 15 dots) containing 0, 2 or 4 pairs of dots grouped by ICs lines. In Experiment 2, participants were presented only the test stimulus and performed an estimation task. Results clearly showed that in both experiments participants' performance followed well-known numerical signatures (e.g., distance effect and scalar variability), with numerosity that was underestimated as the illusory connections increased. Crucially, this was found despite spatial frequencies and luminance were kept constant across all the experimental stimuli and these variables were thus uninformative about numerosity. Taken together, these findings indicate that power spectrum in its own cannot explain numerical processing. Rather, visual segmentation mechanisms may be crucial in such processing at least for a moderate numerosity range.

The effects of hemispheric dominance, literacy acquisition, and handedness on the development of visuospatial attention: A study in preschoolers and second graders.

A tendency to over-attend the left side of the space (i.e., pseudoneglect) has been repeatedly reported in Western adult populations and is supposed to reflect a right hemisphere dominance in the control of visuospatial attention. This neurobiological hypothesis has been partially challenged by growing evidence showing that pseudoneglect is profoundly triggered by cultural practices such as reading and writing habits. Accordingly, more recent theoretical accounts suggest a strict coupling between nature and nurture dimensions at the origins of such bias. To further explore this possibility, here we first administered a digitized cancellation task to right-handed Western children before and after literacy acquisition. Results showed an incremental leftward shift of attention in the cancellation of the first target and an increasing preference for a left-to-right visual search from preschoolers to second graders. Yet, despite these differences, the overall distribution of visuospatial attention was biased to the left in both groups. To explore the role of handedness in visuospatial asymmetries, we also tested a group of left-handed second graders. Results showed an impact of handedness on visuospatial performance, with an accentuated rightward-oriented visual search for left-handed children, although the overall distribution of attention was again biased to the left hemispace. Taken together, these findings do not provide support to a pure neurobiological view of visuospatial biases. Rather, our study indicates that the control of visuospatial attention is mediated by a dynamic interplay among biological (i.e., right hemisphere dominance), biomechanical (i.e., hand dominance), and cultural (i.e., reading habits) factors.

More far is more right: Manual and ocular line bisections, but not the Judd illusion, depend on radial space.

Line bisection studies generally find a left-to-right shift in bisection bias with increasing distance between the observer and the target line, which may be explained by hemispheric differences in the processing of proximo-distal information. In the present study, the segregation between near and far space was further characterized across the motor system and contextual cues. To this aim, 20 right-handed participants were required to perform a manual bisection task of simple lines presented at three different distances (60, 90, 120 cm). Importantly, the horizontal spatial location of the line was manipulated along with the viewing distance to investigate more deeply the hemispheric engagement in the transition from near to far space. As the motoric component of the manual task producing activations of left premotor and motor areas may be partially responsible for the observed transition, participants were also involved in an ocular bisection task. Further, participants were required to bisect Judd variants of the target lines, which are known to elicit a Müller-Lyer-type illusion. Since the Judd illusion depends on areas in the ventral visual stream, we predicted that line bisections of Judd-type lines would be unaffected by viewing distance. Results showed that manual bisection of simple lines was modulated separately by viewing distance and the hemispace of presentation, with this pattern being similar for ocular bisection. Critically, bisections in the Judd illusion task were not modulated by viewing distance, whether performed by hand or by eye. Overall, these findings support the hypothesis that the right hemisphere plays a dominant role in the processing of space close to the body. They also present novel evidence for a general reduction of this dominance at farther distances, whether hand motor actions are involved or not. Finally, our study documents a dissociation between the processing of pure visuospatial information and that of a visual illusion as a function of viewing distance, supporting more generally the dorsal/near space and the ventral/far space segregation.

Cultural and biological factors modulate spatial biases over development.

Increasing evidence supports the contribution of both biological and cultural factors to visuospatial processing. The present study adds to the literature by exploring the interplay of perceptual and linguistic mechanisms in determining visuospatial asymmetries in adults (Experiment 1) and children (Experiment 2). In particular, pre-schoolers (3 and 5 year-olds), school-aged children (8 year-old), and adult participants were required to bisect different types of stimuli, that is, lines, words, and figure strings. In accordance with the literature, results yielded a leftward bias for lines and words and a rightward bias for figure strings, in adult participants. More critically, different biases were found for lines, words, and figure strings in children as a function of age, reflecting the impact of both cultural and biological factors on the processing of different visuospatial materials. Specifically, an adult-like pattern of results emerged only in the older group of children (8 year-old), but not in pre-schoolers. Results are discussed in terms of literacy, reading habits exposure, and biological maturation.

Happiness takes you right: the effect of emotional stimuli on line bisection.

Emotion recognition is mediated by a complex network of cortical and subcortical areas, with the two hemispheres likely being differently involved in processing positive and negative emotions. As results on valence-dependent hemispheric specialisation are quite inconsistent, we carried out three experiments with emotional stimuli with a task being sensitive to measure specific hemispheric processing. Participants were required to bisect visual lines that were delimited by emotional face flankers, or to haptically bisect rods while concurrently listening to emotional vocal expressions. We found that prolonged (but not transient) exposition to concurrent happy stimuli significantly shifted the bisection bias to the right compared to both sad and neutral stimuli, indexing a greater involvement of the left hemisphere in processing of positively connoted stimuli. No differences between sad and neutral stimuli were observed across the experiments. In sum, our data provide consistent evidence in favour of a greater involvement of the left hemisphere in processing positive emotions and suggest that (prolonged) exposure to stimuli expressing happiness significantly affects allocation of (spatial) attentional resources, regardless of the sensory (visual/auditory) modality in which the emotion is perceived and space is explored (visual/haptic).

Numbers reorient visuo-spatial attention during cancellation tasks.

Numbers induce shifts of spatial attention on the left or the right sides of external space as a function of their magnitude. However, whether this number-space association is restricted to the linear horizontal extensions, or extends to the whole visual scene, is still an open question. This study investigates, by means of a cancellation paradigm, the influence of numerical magnitude during scanning tasks in which participants freely explore complex visual scenes unconstrained towards either the horizontal or the vertical unidimensional axes. Five cancellation tasks were adapted in which Arabic digits were used as targets or distracters, in structured (lines and columns) or unstructured visual displays, with a smaller (2 or 3 types of distracters) or larger (10 or more types of distracters) sets of stimuli. Results show that the participants' hits distribution was a function of number magnitude: shifted on the left for small and on the right for large numbers. This effect was maximised when numerical cues were sparse, randomly arranged and, critically, irrelevant to the task. Overall, this study provides novel evidence from visuo-spatial exploratory cancellation tasks for an attentional shift induced by number magnitude.

Temporal perception in closed-skill sports: An experimental study on expert swimmers and runners.

The cognitive benefits of closed-skill sports practice have so far been scantily investigated. Here, we thus focused on the potential impact of swimming and running - two sports that highly rely on a precise control of timing - on time processing. To investigate the impact of these closed-skill sports on time perception and estimation, three groups of participants (for a total of eighty-four young adults) took part in the present study: expert swimmers, expert runners, and non-athletes. The ability to process temporal information in the milliseconds and seconds range was assessed through a time reproduction and a finger-tapping tasks, while a motor imagery paradigm was adopted to assess temporal estimation of sport performance in a wider interval range. We also employed the Vividness of Movement Imagery Questionnaire to assess the individual's ability of motor imagery. Results showed that closed-skill sports, specifically time-related disciplines, enhance motor imagery and time perception abilities. Swimmers were more accurate and consistent in perceiving time when compared to runners, probably thanks to the sensory muffled environment that leads these athletes to be more focused on the perception of their internal rhythm.

Cognitive Reserve Potential: Capturing Cognitive Resilience Capability in Adolescence.

Cognitive reserve (CR) represents the adaptive response of the cognitive system responsible for preserving normal functioning in the face of brain damage. Experiential factors such as education, occupation, and leisure activities influence the development of CR. Theoretically, such factors build up from childhood and across adulthood. Thus, appropriate tools to define and measure CR as early as adolescence are essential to understand its developmental processes. To this aim, we introduce the construct of "Cognitive Reserve Potential" (CRP) and its corresponding index of experiential factors tailored to youth. We investigated prototypical youth exposures potentially associated with the lifelong development of CR (e.g., sport practice, musical experiences, cultural activities, and relationships with peers and family). Principal component analysis and confirmatory factor analysis identified and replicated the CRP factor structure on two independent samples of Italian students: N = 585 (295 F) and N = 351 (201 F), ages 11 to 20. CRP was associated mainly with family socio-cultural status (i.e., socioeconomic status [SES], Home Possessions, and Books at Home). Results confirmed the strength of the factorial model and warranted the proposal of the CRP-questionnaire as an innovative tool for understanding CR evolutionary dynamics.

Finding the spatial-numerical association of response codes (SNARC) in signed numbers: notational effects in accessing number representation.

The present study investigates basic numerical processing in deaf signers and hearing individuals by evaluating notational effects (Arabic digits vs Italian sign language number signs) and response modality (manual vs pedal) in a parity judgment task. Overall, a standard SNARC effect emerged in both groups, suggesting similar numerical representation in hearing and deaf individuals. With the exception of Italian sign language stimuli in the hearing group, this effect applied to all stimuli notations and to both response modalities. In line with the special status of signs, the visuospatial complexity of finger configurations (i.e. number of extended fingers) affected the performance of the hearing group to a greater extent. Finally, the SNARC effect emerged systematically across lateralized effectors(manual/pedal response), challenging the hypothesis that the stimulus-response compatibility effect is specific to the effectors associated with the production of written and sign language. As for parity processing, both groups were similarly influenced by the parity information conveyed by the dominant hand, indicating the compositional nature of number signs irrespective of the preferred language modality.

Spatial frequency equalization does not prevent spatial-numerical associations.

There is an intense debate surrounding the origin of spatial-numerical associations (SNAs), according to which small numbers are mapped onto the left side of the space and large numbers onto the right. Despite evidence suggesting that SNAs would emerge as an innate predisposition to map numerical information onto a left-to-right spatially oriented mental representation, alternative accounts have challenged these proposals, maintaining that such a mapping would be the result of a mere spatial frequency (SF) coding of any visual image. That is, any smaller or larger array of objects would naturally contain more low or high SF information and, accordingly, each hemisphere would be preferentially tuned only for one SF range (e.g., right hemisphere tuned for low SF and left hemisphere tuned for high SF). This would determine the typical SNA (e.g., faster RTs for small numerical arrays with the left hand and for large numerical arrays with the right hand). To directly probe the role of SF coding in SNAs, we tested participants in a typical dot-arrays comparison task with two numerical sets: one in which SFs were confounded with numerosity (Experiment 1) and one in which the full SF power spectrum was equalized across all stimuli, keeping this cue uninformative about numerosity (Experiment 2). We found that SNAs emerged in both experiments, independently of whether SF was confounded or not with numerosity. Taken together, these findings suggest that SNAs cannot simply originate from SF power spectrum alone, and, thus, they rule out the brain's asymmetric SF tuning as a primary cause of such an effect.

Number is not just an illusion: Discrete numerosity is encoded independently from perceived size.

While seminal theories suggest that nonsymbolic visual numerosity is mainly extracted from segmented items, more recent views advocate that numerosity cannot be processed independently of nonnumeric continuous features confounded with the numerical set (i.e., such as the density, the convex hull, etc.). To disentangle these accounts, here we employed two different visual illusions presented in isolation or in a merged condition (e.g., combining the effects of the two illusions). In particular, in a number comparison task, we concurrently manipulated both the perceived object segmentation by connecting items with Kanizsa-like illusory lines, and the perceived convex-hull/density of the set by embedding the stimuli in a Ponzo illusion context, keeping constant other low-level features. In Experiment 1, the two illusions were manipulated in a compatible direction (i.e., both triggering numerical underestimation), whereas in Experiment 2 they were manipulated in an incompatible direction (i.e., with the Ponzo illusion triggering numerical overestimation and the Kanizsa illusion numerical underestimation). Results from psychometric functions showed that, in the merged condition, the biases of each illusion summated (i.e., largest underestimation as compared with the conditions in which illusions were presented in isolation) in Experiment 1, while they averaged and competed against each other in Experiment 2. These findings suggest that discrete nonsymbolic numerosity can be extracted independently from continuous magnitudes. They also point to the need of more comprehensive theoretical views accounting for the operations by which both discrete elements and continuous variables are computed and integrated by the visual system.

Nonsymbolic numerosity in sets with illusory-contours exploits a context-sensitive, but contrast-insensitive, visual boundary formation process.

The visual mechanisms underlying approximate numerical representation are still intensely debated because numerosity information is often confounded with continuous sensory cues (e.g., texture density, area, convex hull). However, numerosity is underestimated when a few items are connected by illusory contours (ICs) lines without changing other physical cues, suggesting in turn that numerosity processing may rely on discrete visual input. Yet, in these previous works, ICs were generated by black-on-gray inducers producing an illusory brightness enhancement, which could represent a further continuous sensory confound. To rule out this possibility, we tested participants in a numerical discrimination task in which we manipulated the alignment of 0, 2, or 4 pairs of open/closed inducers and their contrast polarity. In Experiment 1, aligned open inducers had only one polarity (all black or all white) generating ICs lines brighter or darker than the gray background. In Experiment 2, open inducers had always opposite contrast polarity (one black and one white inducer) generating ICs without strong brightness enhancement. In Experiment 3, reverse-contrast inducers were aligned but closed with a line preventing ICs completion. Results showed that underestimation triggered by ICs lines was independent of inducer contrast polarity in both Experiment 1 and Experiment 2, whereas no underestimation was found in Experiment 3. Taken together, these results suggest that mere brightness enhancement is not the primary cause of the numerosity underestimation induced by ICs lines. Rather, a boundary formation mechanism insensitive to contrast polarity may drive the effect, providing further support to the idea that numerosity processing exploits discrete inputs.

The ratio effect in visual numerosity comparisons is preserved despite spatial frequency equalisation.

How non-symbolic numerosity is visually extracted remains a matter of intense debate. Most evidence suggests that numerosity is directly extracted on individual objects following Weber's law, at least for a moderate numerical range. Alternative accounts propose that, whatever the range, numerosity is indirectly derived from summary texture-statistics of the raw image such as spatial frequency (SF). Here, to disentangle these accounts, we tested whether the well-known behavioural signature of numerosity encoding (ratio effect) is preserved despite the equalisation of the SF content. In Experiment 1, participants had to select the numerically larger of two briefly presented moderate-range numerical sets (i.e., 8-18 dots) carefully matched for SF; the ratio between numerosities was manipulated by levels of increasing difficulty (e.g., 0.66, 0.75, 0.8). In Experiment 2, participants performed the same task, but they were presented with both the original and SF equalised stimuli. In both experiments, the results clearly showed a ratio-dependence of the performance: numerosity discrimination became harder and slower as the ratio between numerosities increased. Moreover, this effect was found to be independent of the stimulus type, although the overall performance was better with the original rather than the SF equalised stimuli (Experiment 2). Taken together, these findings indicate that the power spectrum per se cannot explain the main behavioural signature of Weber-like encoding of numerosities (the ratio effect), at least over the tested numerical range, partially challenging alternative indirect accounts of numerosity processing.

Visual illusions as a tool to hijack numerical perception: Disentangling nonsymbolic number from its continuous visual properties.

The past few years have witnessed a fervent theoretical debate about the exact visual mechanisms supporting nonsymbolic number processing. The idea that quantity information is extracted through a primitive visual segmentation algorithm has been challenged by recent models, which rather tap on low-level features confounded with numerosity (i.e., density, convex hull, or total area). Here we used an original manipulation based on visual illusions to disentangle whether visual numerosity processing operates over discrete units or rather over continuous variables. In particular, we generated a set of stimuli composed by open inducers (e.g., like a pac-man shape) that simulate physical connections with Kanizsa-like illusory contours (ICs). Test sets contained pairs of collinear open inducers items that prompted 0 IC, 2 IC, or 4 IC lines connecting 2 objects. Critically, low-level visual features were fully controlled across connectedness levels. We found a systematic underestimation as we increased the IC connections when participants had to select the larger between 2 sets of objects (Experiment 1) but not in the case of aligned closed inducers preventing illusory lines (Experiments 2A and 2B). We also found a systematic numerosity underestimation when both IC connections and continuous features (e.g., convex hull) were independently manipulated in test stimuli (Experiment 3). Finally, these results were shown to be task independent because the same effects of IC connections were replicated in an estimation task (Experiment 4). Taken together, our findings indicate that numerosity perception relies on basic visual-segmentation mechanisms, pointing out the need of new theoretical frameworks integrating both continuous and discrete perceptual number signals. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Placing order in space: the SNARC effect in serial learning.

The SNARC effect, consisting of a systematic association between numbers and lateralized response, reflects the mental representation of magnitude along a left-to-right mental number line (Dehaene et al. in J Exp Psychol 122:371-396, 1993). Critically, this effect has been reported in the classification of overlearned non-numerical sequences such as letters, days and months (Gevers et al. in Cognition 87:B87-B95, 2003 and Cortex 40:171-172, 2004) suggesting that ordinal, rather than magnitude information, is critical for spatial coding. This study tests the hypothesis of an oriented spatial representation as the privileged way of mentally organizing serial information, by looking for stimulus-response compatibility effects in the processing of a newly acquired arbitrary sequence. Here we report an association between ordinal position of the items and spatial response preference for both order-relevant and order-irrelevant tasks. These results suggest that any ordered information, even when order is not intrinsically relevant to it, is spontaneously mapped in the representational space. This spatial representation is likely to acquire a left-to-right orientation, at least in western cultures.

Numbers can move our hands: a spatial representation effect in digits handwriting.

The interaction between numbers and action-related processes is currently one of the most investigated topics in numerical cognition. The present study contributes to this line of research by investigating, for the first time, the effects of number on an overlearned complex motor plan that does not require explicit lateralised movements or strict spatial constrains: spontaneous handwriting. In particular, we investigated whether the spatial mapping of numbers interferes with the motor planning involved in writing. To this aim, participants' spontaneous handwriting of single digits (Exp. 1) and letters (Exp. 2) was recorded with a digitising tablet. We show that the writing of numbers is characterised by a spatial dislocation of the digits as a function of their magnitude, i.e., small numbers were written leftwards relative to large numbers. In contrast, the writing of letters showed a null or marginal effect with respect to their dislocation on the writing area. These findings show that the automatic mapping of numbers into space interacts with action planning by modulating specific motor parameters in spontaneous handwriting.

Seven-month-olds detect ordinal numerical relationships within temporal sequences.

Previous evidence has shown that 11-month-olds represent ordinal relations between purely numerical values, whereas younger infants require a confluence of numerical and non-numerical cues. In this study, we show that when multiple featural cues (i.e., color and shape) are provided, 7-month-olds detect reversals in the ordinal direction of numerical sequences relying solely on number when non-numerical quantitative cues are controlled. These results provide evidence for the influence of featural information and multiple cue integration on infants' proneness to detect ordinal numerical information.

How difficult is it for adolescents to maintain attention? The differential effects of video games and sports.

Despite a large body of evidence suggests positive effects of playing action video games and practising sports on various visual attentional skills, the impact of these activities on the ability to maintain attention over prolonged periods of time (i.e., sustained attention) has been largely neglected. Here, we first explored free-time habits on a group of 310 adolescents by means of a self-reported questionnaire. We found an inverse relationship between the time spent with sports and video games, but not with other extra-scholastic activities: the time spent practising sports and playing video games clearly competed with each other, with the more-intensive-sport practitioners being less involved in video game play. Next, we directly measured sustained attention and other attentional skills in a subgroup of 76 participants, divided as a function of their time spent in sports and action video games. In particular, sustained attention was assessed by means of two tasks: a classic exogenous task, requiring participants to attend to a flashing visual stimulus; and an internal (endogenous) sustained attention task, requiring participants to synchronise their manual responses to the rhythm of auditory pulses presented in an earlier phase. As previously documented, we found that action video game players displayed worse ability to maintain attention over time, as compared with non-action players. In striking contrast, intensive sports practice was associated with an increased ability to maintain attention over time. Overall, these findings unveil distinct cascading effects on sustained attention induced by doing sport and playing action video games.

Colours + Numbers differs from colours of numbers: cognitive and visual illusions in grapheme-colour synaesthesia.

This study investigates the bi-directionality of synaestesic experience by means of a flanked bisection paradigm in TT, a number-colour synaesthete. Previous studies have shown that bisection is shifted towards the larger digit flanker (e.g., Ranzini & Girelli, 2012). TT and controls performed line bisections with lines flanked by black digits (experiment 1), by TT's photism colours (experiment 2), and by congruently (experiment 3), or incongruently coloured digits (experiment 4). While the results of the control group mainly replicated previous findings, only the colour-digit congruence elicited in TT the larger-digit bias. TT's absence of effects in the other conditions was not due to reduced sensitivity to luminance effects (experiment 5), or to mathematical expertise (experiment 6). We suggest that grapheme-colour synaesthesia might be characterised by a rigid access to semantic representation when the inducer is task-irrelevant.