Increasing magnitude counts more: asymmetrical processing of ordinality in 4-month-old infants

While infants' ability to discriminate quantities has been extensively studied, showing that this competence is present even in neonates, the ability to compute ordinal relations between magnitudes has received much less attention. Here we show that the ability to represent ordinal information embedded in size-based sequences is apparent at 4months of age, provided that magnitude changes involve increasing relations. Infants in Experiments 1A and 1B discriminated changes in ordinal relations after habituation to ascending sequences, but did not show evidence of discrimination after habituation to descending sequences. In Experiment 2 we replicated this asymmetry in magnitude discrimination even when additional cues known to boost ordinal competence were provided. The presence of an asymmetry between ascending vs. descending order during infancy suggests a developmental continuity in the underlying code used to represent magnitude, whereby the reported addition advantage in children and adults' arithmetic performance emerges.     

The own‐age face recognition bias is task dependent

The own‐age bias (OAB) in face recognition (more accurate recognition of own‐age than other‐age faces) is robust among young adults but not older adults. We investigated the OAB under two different task conditions. In Experiment 1 young and older adults (who reported more recent experience with own than other‐age faces) completed a match‐to‐sample task with young and older adult faces; only young adults showed an OAB. In Experiment 2 young and older adults completed an identity detection task in which we manipulated the identity strength of target and distracter identities by morphing each face with an average face in 20% steps. Accuracy increased with identity strength and facial age influenced older adults' (but not younger adults') strategy, but there was no evidence of an OAB. Collectively, these results suggest that the OAB depends on task demands and may be absent when searching for one identity.     

Small on the left,large on the right: numbers orient visual attention onto space in preverbal infants

Numbers are represented as ordered magnitudes along a spatially oriented number line. While culture and formal education modulate the direction of this number–space mapping, it is a matter of debate whether its emergence is entirely driven by cultural experience. By registering 8–9‐month‐old infants’ eye movements, this study shows that numerical cues are critical in orienting infants’ visual attention towards a peripheral region of space that is congruent with the number's relative position on a left‐to‐right oriented representational continuum. This finding provides the first direct evidence that, in humans, the association between numbers and oriented spatial codes occurs before the acquisition of symbols or exposure to formal education, suggesting that the number line is not merely a product of human invention.     

The early development of human mirror mechanisms: evidence from electromyographic recordings at 3 and 6 months

In primates and adult humans direct understanding of others' action is provided by mirror mechanisms matching action observation and action execution (e.g. Casile, Caggiano & Ferrari, 2011). Despite the growing body of evidence detailing the existence of these mechanisms in the adult human brain, their origins and early development are largely unknown. In this study, for the first time, electromyographic (EMG) measures were used to shed light on the emergence of mirror motor mechanisms in infancy. EMG activity was recorded while 6‐ and 3‐month‐old infants watched two videos displaying an agent reaching for, grasping and bringing an object either to the mouth or to the head. Results indicate that the motor system of 6‐month‐olds, but not 3‐month‐olds, was recruited and selectively modulated during observation of the goal‐directed actions, favoring the idea that mirror mechanisms driving action understanding gradually emerge during early development.     

The neural correlates of processing newborn and adult faces in 3‐year‐old children

The current study examines the processing of upright and inverted faces in 3‐year‐old children (n = 35). Event‐related potentials (ERPs) were recorded during a passive looking paradigm including adult and newborn face stimuli. We observed three face‐sensitive components, the P1, the N170 and the P400. Inverted faces elicited shorter P1 latency and larger P400 amplitude. P1 and N170 amplitudes were larger for adult faces. To examine the role of experience in the development of face processing, the processing of adult and newborn faces was compared for children with a younger sibling (n = 23) and children without a younger sibling (n = 12). Age of sibling at test correlated negatively with P1 amplitude for adult and newborn faces. This may indicate more efficient processing of different face ages in children with a younger sibling and potentially reflects a more flexible face representation.     

Comments on “Getting scarred and winning lotteries: Effects of exemplar cuing and statistical format on imagining low‐probability events,” By Newell,Mitchell, and Hayes (2008)

Newell, Mitchell, and Hayes (NMH) conduct three experiments designed to test whether exemplar cuing (EC) theory or a statistical format theory provides a more accurate account for how people make judgments about low‐probability events. They report finding support for the statistical format theory and little or no support for EC. However, NMH misstate the requirements for the production of exemplars in EC theory. As a result, they confuse non‐exemplar conditions with exemplar conditions in their experiments, and find results that are virtually irrelevant to EC theory. Copyright © 2009 John Wiley & Sons, Ltd.     

No own-age bias in 3-year-old children: More evidence for the role of early experience in building face-processing biases

This study aimed to investigate the presence of an own-age bias in young children who accumulated different amounts of early experience with child faces. Discrimination abilities for upright and inverted adult and child faces were tested using a delayed two-alternative, forced-choice matching-to-sample task in two groups of 3-year-old children, one composed of first-born children and the other composed of children who, from the time of their birth, had daily exposure to a child face through the presence of an older sibling in their home. Children without an older sibling were better at differentiating among adult faces than among child faces and showed an inversion effect that was selective for adult faces. Children with an older sibling were equally skilled at differentiating upright adult and child faces and showed inversion effects of comparable magnitude for both face types. Results support the notion that face representational space of younger children is tuned to adult faces and suggest that age biases during early childhood are dependent on the effects of early experience.