Mauro Murgia

According to the neural overlap hypothesis (Fias et al., 2001), numerical magnitude may influence performance in a non-semantic task when the processing of task-relevant and task-irrelevant information recruits overlapping neural structures. Specifically, because number and orientation processing both engage parietal regions, the account predicts a SNARC effect during orientation judgments, whereas effects should be weaker in tasks with less parietal involvement, such as colour judgments. However, only a few studies have attempted to replicate the original findings. Here, we conducted a large-sample replication of the line orientation task introduced by Fias et al. (2001, Experiment 4) and included letters as a complementary condition. Across two experiments, conducted online and in the laboratory, we consistently failed to detect a SNARC effect for numbers or a SNARC-like effect for letters. A cumulative analysis likewise provided no evidence for either association. These findings fail to replicate a key result supporting the neural overlap hypothesis and suggest that shared parietal processing may not give rise to spatial-numerical associations as robustly as previously assumed.

Recent evidence suggests the existence of spatial associations for musical tempo, characterized by faster left-key responses to relatively slow tempos and faster right-key responses to relatively fast tempos. However, while this effect has been consistently observed in the fast tempo range (133–201 bpm), previous studies investigating the slow tempo range (e.g., 40–104 bpm) have failed to find a reliable effect, reporting null or contradictory findings. The present study investigated whether a spatial association exists in the slow tempo range when specific methodological limitations (i.e. excessive gaps between stimuli) are addressed. Specifically, the study aimed to increase stimulus density through two complementary approaches: (1) testing the “absolute gap hypothesis” by using a physically linear scale with reduced intervals (“physical linearity condition”), and (2) testing the “proportional gap hypothesis” by using a perceptually linear scale based on Weber’s Law (“perceptual linearity condition”). The results revealed a significant spatial association in both conditions, demonstrating that a denser set of stimuli facilitates the emergence of spatial mappings regardless of the scaling method. These findings demonstrate that ensuring temporal continuity through increased stimulus density reveals a robust spatial association in the slow tempo range, thereby supporting a unified mechanism for temporal processing consistent with a generalized magnitude system.

Spatial Numerical Associations (SNAs) refer to the compatibility between space and numerical magnitude. They are commonly operationalized as faster left-hand responses to small numbers and faster right-hand responses to large numbers (R/SNA). By contrast, the compatibility between stimulus spatial position and numerical magnitude (S/SNA) has received little attention. We disentangled R/SNA and S/SNA contributions for peripheral target numbers, with their magnitude being either task-irrelevant or task-relevant, while also manipulating the spatial position-response hand compatibility (S/R). Across two Posner exogenous cueing experiments, we orthogonally varied target spatial position (left/right), cue validity (valid/neutral/invalid), and the S/R-compatibility (S/R-compatible/incompatible). Experiment 1 employed a magnitude classification task, and Experiment 2 a localization task. We applied a chronometric framework to decompose response latencies into three components: reflexive attention (cue-driven), voluntary attention (target-driven), and response planning. In Experiment 1, SNAs were driven by the response planning component and were progressively inhibited by voluntary attention, decreasing from the valid to the invalid cue condition. In Experiment 2 SNAs emerged in the invalid cues condition only, suggesting that they were driven by the voluntary attention component. Notably, S/R exhibited a striking reversal: in Experiment 1, it was driven by voluntary attention, whereas in Experiment 2, it hinged on response planning and was actually suppressed by voluntary attention. These results align with a relative-dependence framework, suggesting that compatibility effects are guided by either voluntary attention or response planning, depending on whether the critical dimension underlying the effect is explicit or implicit.

The SNARC effect indicates that numbers are mapped from left to right as in a mental number line. Accumulating evidence suggests that it could be attributed both to the magnitude or to the order of numbers, but the role of these two aspects has not yet been disambiguated since the two are tightly correlated. This study investigated the influence of order and magnitude in the SNARC effect using playing cards as stimuli. While most people organize cards in ascending order (AO), according to the Western reading-writing direction, a minority of people arrange them in descending order (DO). In this regard DO people should spontaneously associate low magnitude cards (e.g., 2) to the right, and high magnitude cards (e.g., 6) to the left. Therefore, in DO individuals, cards’ order would elicit a spatial mapping opposite to the canonical mapping of quantities (i.e., mental number line). In Experiment 1, DO participants performed magnitude classification on simple numerals and on playing cards, showing a regular SNARC effect when classifying numbers and no significant effect when classifying cards. Conversely, in Experiment 2, AO participants showed a regular SNARC effect when classifying both numbers and cards. In Experiment 3, a separate group of DO participants was recruited and tested online to replicate Experiment 1 and clarify the occurrence of spatial associations in card classification. Results indicated that DO participants showed regular SNARC effects both in number and card classification, suggesting that magnitude played a key role overruling the order of cards. This is apparently in contradiction with the view that specific experiences with ordered stimuli should determine the direction of an association.

Time is often conceptualised in spatial terms. For example, concepts such as ‘before’ and ‘after’ are frequently mapped onto the left and right sides of space, respectively. Importantly, such spatial mapping typically disappears when time is processed as a task-irrelevant dimension. In the present study, we further investigated this phenomenon using highly salient and socially relevant stimuli: human faces varying in age. We conducted two experiments using the same paradigm, in which the age of a female and a male face was processed either explicitly (Experiment 1; N = 120, 50% females) or implicitly (Experiment 2; N = 120, 50% females). In Experiment 1, participants categorised the age of a centrally-presented target face as younger or older than a reference face by pressing left or right keys. In Experiment 2, participants categorised the sex of the face. Both experiments provided evidence consistent with a left-to-right spatial mapping of face age, such that younger faces tended to be associated with the left and older faces with the right, although this effect was more pronounced when age was explicitly processed (Experiment 1). Experiment 2 also revealed a spatial mapping for the sex of the face. Taken together, these findings suggest that human faces are powerful stimuli capable of eliciting spatial representations not only of time, but also of other socially meaningful dimensions, such as sex, likely due to their salience and central role in social perception.

The existence of a conceptual link between numbers and space is a fundamental question in numerical cognition and has been highly debated in recent years. Although Spatial-Numerical Associations (SNAs) have traditionally been investigated using bimanual response settings, recent studies have moved towards unimanual paradigms to avoid potential measurement artifacts. For instance, an influential line of research adopted a modified Implicit Association Test (IAT) in which numbers and arrows were presented sequentially. However, SNAs consistently emerged only when spatial and magnitude codes were explicitly contrasted, questioning the idea that numbers are inherently represented in a spatial format. To further investigate this issue, we designed a modified flanker task in which spatial and numerical stimuli were presented simultaneously. When arrows were task irrelevant (Experiment 1), no significant SNA emerged. By contrast, when participants judged arrow direction and numerical magnitude conjunctively (Experiment 2), the paradigm revealed extremely large SNAs compared to existing literature. Overall, our results provide no evidence for a purely conceptual spatial–numerical link, suggesting that robust SNAs require explicit spatial codes combined with semantic number processing. Finally, the large effect size of group-level SNAs, together with remarkable mixed-model-derived psychometric properties, indicates the modified flanker task as an ideal paradigm for studying individual differences and effect modulations. We suggest that this paradigm has the potential to further advance the research on SNAs by overcoming limitations of previous bimanual and unimanual paradigms and, consequently, by helping to disambiguate mixed results in the literature.

When asked to produce random numbers individuals generate more small numbers than large ones, a phenomenon known as “Small Number Bias” (SNB; Loetscher & Brugger, 2007). This bias has been associated with a spatial preference known as “pseudoneglect,” where attention is biased towards the left side of the mental number line during numerical processing (Loetscher & Brugger, 2009). Another potential explanation for SNB is the higher frequency of use of small compared to large numbers in daily life (Dehaene & Mehler, 1992). This study aims to determine which of these two explanations better accounts for SNB. Participants were asked to generate random numbers from 1 to 12 while viewing either a regular or an inverted clockface. On a regular clockface smaller numbers are on the right, whereas on an inverted clockface they are on the left. Both theories predict SNB for the inverted clockface. However, for the regular clockface, frequency of use would predict SNB, while pseudoneglect would predict a bias towards larger numbers. Results showed SNB in the inverted clockface condition, but no bias in the regular clockface condition. These findings suggest that SNB arises when pseudoneglect and frequency of use align but is absent when they conflict. Overall, the results indicate that both pseudoneglect and frequency of use contribute to SNB in some degrees.

In ball sports, such as volleyball or soccer, the impact sound of the ball is used to define the shot length and predict the final ball position on the field. Several studies thoroughly investigated the role of sound intensity in predicting the ball's landing point, neglecting the equally important contribution of the sound frequency spectrum component. Here, we investigated the contribution of the sound frequency spectrum in defining a volleyball serve's length (i.e., distance). We recorded the sound of short and long volleyball serves (ecological sound) and changed their frequency spectrum in pink noise, preserving their intensity (noise sound). We then presented both sounds (ecological and noise) to expert volleyball players and measured their performance in short and long-shot classifications. The role of auditory-motor experience in sound classification was also explored by testing soccer players (experience on ball shots but not sport-specific auditory-motor experience) and non-athletes (no auditory-motor experience in sports). We found that hearing ecological sound leads to better sound discrimination performance than noise sound. Concurrently, we found an effect of the specific auditory-motor experience, with volleyball players outperforming non-athletes and soccer players. Interestingly, experts in different sports domains (soccer players) mainly used sound intensity for shot classification. This underlines the importance of specific auditory-motor experience in encoding specific sound frequency spectrum for the sound of action classification.

Starting approximately from the beginning of the new millennium, a series of studies highlighted that auditory information deriving from biological motion can significantly influence the behavioral, cognitive and neurophysiological processes involved in the perception and execution of complex movements. In particular, it was observed that an appropriate use of sounds deriving from one’s own movement promotes improvements in the movement execution itself. Two main approaches can be used, namely the sonification one or the ecological sound one; the former is based on the conversion of physiological and/or physical movement data into sound, while the latter is based on the use of auditory recordings of movement sounds as models. In the present article, some of the main applications of both approaches—especially the latter—to the domains of sport and motor rehabilitation are reviewed, with the aim of addressing two questions: Is it possible to consider rhythm as a Gestalt of human movement? If so, is it possible to build up cognitive strategies to improve/standardize movement performance from this Gestalt? As with most topics in science, a definitive answer is not possible, yet the evidence leads us to lean toward a positive answer to both questions.