The Realm of Magnitude Representations: Origins and Neural Basis – NUMSPA

We have conducted both behavioral and neuroimaging studies on human newborns aged of a few hours, as well as on preverbal infants in their first year of life, so as to understand the origins, neural bases, and properties of the ability to represent magnitude information from birth and through the first months of life. We have measured newborns’ and infants’ cerebral activation during sleep while presented with auditory stimulation, as well as their active responses during an active alert state with simultaneous auditory and visual stimulation. Our behavioral studies have allowed us to understand whether, for instance, humans at birth associate small quantities to the left and large quantities to the right side of space, whether they establish associations between all quantity dimensions, and whether the use of space contributes to learning ordinal sequences in older infants.

The results of these studies suggest that at the start of postnatal life number establishes a privileged link with space that extends only partially to the dimension of brightness. Also, numerosities, but not space or duration, are associated to different spatial locations depending on their relative magnitude, small vs. large, strengthening the view of the existence of a privileged link between number and space that is functional from birth. We have also observed that, during the first year of life, spatial presentation of ordinal information can contribute to the processing and learning of sequential information.

There are several questions open for future research. For instance, we do not know when exactly the influence of culture in these mappings takes place. While we know that his influence is functional already in childhood, with children using a left-to-right vs. a right-to-left mapping depending on the spatial biases of their culture (Western left-to-right vs. Arabic right-to-left; Shaki et al., 2012), we lack knowledge on how early our basic biases are modulated by the specific cultural environment we are living in. It is possible that this influence might take place during the first year of life, as we interact with other individuals that demonstrate their own spatial biases. Future research will need to show when exactly this cultural shift takes place. Another issue concerns the practical utility of having such a directional mapping bias. In fact, we do not know whether having this particular bias has direct consequences from an evolutionary point of view, as it could be a by-product of hemispheric asymmetry, which by itself could have advantages or be completely casual. Current research is addressing the origins of these spatial-numerical biases. According to our view (de Hevia et al., 2012), a bias to start a visual scan with the left side of space is paired with a bias to prefer sequences that increase in magnitude (de Hevia et al., 2014, 2017). It is therefore a spatial bias that gives rise to the lateralized processing of number seen from birth. We are testing whether the left hemispace advantage, driven by our hemispheric asymmetries and present in children and adults, is already functional at birth, and therefore that already from birth newborns privilege information located on the left side of space.

Our experimental studies have been recently published in high impact journals, such as Cognition (de Hevia et al., 2016), Scientific Reports (Bulf, de Hevia et al., 2017), and Current Biology (de Hevia et al., 2017), and have been presented in various international conferences, such as Society for functional Near Infrared Spectroscopy (2016), International Society for Infant Studies (2016, 2018), Cognitive Development Society (2017), and Mathematical Cognition and Learning Society (2018). Moreover, we have published several opinion pieces and critical reviews of the literature (de Hevia, 2016, Progress in Brain Research; de Hevia et al., 2017, Behavior Brain Sciences; de Hevia et al., 2017, Timing & Time Perception Reviews; McCrink & de Hevia, 2018, Frontiers in Psychology).

A rich concept of magnitude --in its numerical, spatial and temporal forms-- is a central foundation of mathematics, science and technology, but the origins, developmental relations, and format of the abstract concepts of number, space and time are still debated and poorly understood. Understanding how the concepts of magnitude are represented, understood, and the intuitions that guide reasoning about them is essential for the design of early childhood programs that promote academic skills. Shedding light on this phenomenon has far reaching implications for our society. In fact, mathematics is at the centre of the children’s school curricula, and one of the foundations of mathematics education is the understanding of number. Children’s ability to relate number and space therefore might enhance children’s achievement of an adequate number knowledge. There are a number of pressing questions characterizing research on this topic: what are the functional origins of the mappings between different magnitude dimensions: do they represent instances of a more general ability to relate any continuous dimension, or is the connection between the representations of space-time-number specific to these dimensions? Moreover, what are the neural bases for this phenomenon in the immature brain? Tasks 1 and 2 of this project address these two fundamental questions through behavioral and neuroimaging studies of newborns. These studies can inform fundamental questions about innateness, addressing longstanding topics of study, from the dawn of philosophy and experimental psychology, to classical developmental psychology and modern cognitive science, and will contribute knowledge with critical implications for education and neuropsychology.