Categorization in infancy: labeling induces a persisting focus on commonalities

Recent studies with infants and adults demonstrate a facilitative role of labels in object categorization. A common interpretation is that labels highlight commonalities between objects. However, direct evidence for such a mechanism is lacking. Using a novel object category with spatially separate features that are either of low or high variability across the stimulus set, we tracked 12-month-olds' attention to object features during learning and at test. Learning occurred in both conditions, but what was learned depended on whether or not labels were heard. A detailed analysis of eye movements revealed that infants in the two conditions employed different object processing strategies. In the silent condition, looking patterns were governed exclusively by the variability of object parts. In the label condition, infants' categorization performance was linked to their relative attention to commonalities. Moreover, the commonality focus persisted after learning even in the absence of labels. These findings constitute the first experimental evidence that labels induce a persistent focus on commonalities

Shaping the Dynamics of Category Learning in Infants and Adults by Varying Learning Context

During the first year of life, infants develop a remarkable ability to group objects based on their similarities and differences. This ability of category formation represents one of the main mechanisms underlying the organisation of the semantic system. Early categories are formed spontaneously, in a non-supervised fashion and this type of category acquisition remains present even when more sophisticated forms of supervised category learning emerge. Even though there are various models of categorisation mechanisms across the lifespan, there is a gap in the research investigating implicit categorisation at different stages of cognitive development. Therefore, the aim of the current study was to compare processes of spontaneous concept formation in infants and adults using an experimental paradigm based on novelty preference. We discovered that both infants and adults show evidence of category learning (Experiment 1), though with different amount of training being needed to achieve the task. Adults successfully categorised objects already after a single block of training. Infants reached a level comparable to that of adults after twice the amount of training. As these tasks inevitably pose different cognitive and sensory demands to the two groups, in Experiments 2 and 3 we explored how varying parameters of the learning context affect dynamics of category formation. Decreasing memory demands of the task resulted in an acceleration of infants’ category formation (Experiment 2), whereas posing memory load in an implicit category learning task decelerated adults’ dynamics of category formation (Experiment 3)

Infant categorization as a dynamic process linked to memory

Recency effects are well documented in the adult and infant literature: recognition and recall memory are better for recently occurring events. We explore recency effects in infant categorization, which does not merely involve memory for individual items, but the formation of abstract category representations. We present a computational model of infant categorization that simulates category learning in 10-month-olds. The model predicts that recency effects outweigh previously reported order effects for the same stimuli. According to the model, infant behaviour at test should depend mainly on the identity of the most recent training item. We evaluate these predictions in a series of experiments with 10-month-old infants. Our results show that infant behaviour confirms the model’s prediction. In particular, at test infants exhibited a preference for a category outlier over the category average only if the final training item had been close to the average, rather than distant from it. Our results are consistent with a view of categorization as a highly dynamic process where the end result of category learning is not the overall average of all stimuli encountered, but rather a fluid representation that moves depending on moment-to-moment novelty. We argue that this is a desirable property of a flexible cognitive system that adapts rapidly to different contexts

The role of labels and motions in infant category learning

We investigated the impact of two highly salient transient features, labels and motions, on novel visual category learning in 10-month-old infants. In three eye-tracking experiments, infants were presented with exemplars from two novel categories either accompanied by category-specific labels, accompanied by category-specific motions, or in silence. Labels (Experiment 1) and motions (Experiment 2) were presented using a gaze-contingent design in which these transient features were triggered by infants’ fixations. Gaze-contingent transient features, despite being redundant, had a strong impact on categorization. The results revealed that both labels and motions support infants’ category formation. Furthermore, both labels and motions promoted similarity-focused exploration, whereas no such pattern was found when infants learned the categories in silence. Analyses of visual exploration patterns revealed that infants readily form expectations about motion properties of categories and that these expectations drive their looking behavior

Discovering category boundaries: The role of comparison in infants' novel category learning

A key question in categorization is how infants extract regularities from the exemplars they encounter. Detecting similarities and dissimilarities across items is vital in order to determine category-relevant features. Previous research found evidence that infants acquire a single category more easily with paired presentations in comparison with single presentations (Oakes & Ribar, 2005, Infancy, 7, 85; Oakes & Kovack-Lesh, 2007, Cogniție, Creier, Comportament / Cognition, Brain, Behavior, XI, 661). Here, we focus on infants’ acquisition of a category contrast, that is, when they are exposed to two categories. In an eye-tracking study, we examined 10-month-old infants’ ability to learn two novel visual categories when presented with one item at a time and with items in pairs. Infants were familiarized with pairs of items from the same category or with pairs of items from different categories (cross-category pairs). Using a linear model with a priori contrasts, we show that infants’ learning is directly related to the opportunity for category comparison: There is no evidence of category learning in the single-item condition, improved performance when familiarized with same-category pairs, and finally robust category learning when familiarized with cross-category pairs. We conclude that comparison which involves items from different categories promotes category formation, by highlighting differences and promoting a discovery of category boundaries

Attention to the source domain of conventional metaphorical expressions: Evidence from an eye tracking study

This study investigates whether the metaphorical status of conventional expressions can be reactivated when elements of the source domain are present in the context. In indirect metaphors the source domain (or literal meaning) is not expressed (e.g., The father cut the budget). The literal meaning of cutting remains latently encoded in the predicate and readers' attention is not required to move from the finance domain to the domain of physical cuts. Such conventional metaphoric expressions are likely to be processed via lexical disambiguation of a polysemous (metaphorical) verb. Using an eye tracking combined with a forced-choice semantic relatedness task we investigated whether by adding linguistic material referring to the source domain (e.g., father cut the budget like grass), we can direct readers’ attention to the source domain of the metaphorical predicate and stimulate them to interpret conventional metaphorical expressions by means of cross-domain mapping. The results indicate that in the reactivated condition participants dwell on the object (budget) significantly longer in their second run and when they regress to it after the final region than where there is no source domain activation. These findings may offer new insight into the limited experimental evidence related to the deliberate metaphor theory

Distinct orthography boosts morphophonological discrimination: Vowel raising in Bengali verb inflections

This study is concerned with how vowel alternation, in combination with and without orthographic reflection of the vowel change, affects lexical access and the discrimination of morphologically related forms. Bengali inflected verb forms provide an ideal test case, since present tense verb forms undergo phonologically conditioned, predictable vowel raising. The mid-to-high alternations, but not the low-to-mid ones, are represented in the orthography. This results in three different cases: items with no change (NoDiff), items with a phonological change not represented in the orthography (PronDiff) and items for which both phonology and orthography change (OrthPronDiff). To determine whether these three cases differ in terms of lexical access and discrimination, we conducted two experiments. Experiment 1 was a cross-modal lexical decision task with auditory primes (1 st PERSON and 3 rd PERSON forms, e.g. [lek he] or [lik hi]) and visual targets (verbal noun; e.g. [lek ha]). Experiment 2 uses eye tracking in a fragment completion task, in which auditory fragments (first syllable of 1 st or 3 rd PERSON form, e.g. [le-] from [lek he]) were to be matched to one of two visual targets (full 1 st and 3 rd PERSON forms, [lek he] vs. [lik hi] in Bengali script). While the lexical decision task, a global measure of lexical access, did not show a difference between the cases, the eye-tracking experiment revealed effects of both phonology and orthography. Discrimination accuracy in the OrthPronDiff condition (vowel alternation represented in the orthography) was high. In the PronDiff condition, where phonologically differing forms are represented by the same graphemes, manual responses were at chance, although eye movements revealed that match and non-match were discriminated. Thus, our results indicate that phonological alternations which are not represented in spelling are difficult to process, whereas having orthographically distinct forms boosts discrimination performance, implying orthographically influenced mental phonological representations

Validation psychométrique croisée de la version 3 de SATIN dans deux échantillons.

Ce document complète le travail de validation du questionnaire SATIN dans sa version 3. Il s’agit d’un questionnaire permettant d’agir sur les risques psychosociaux sur lequel l’INRS et l’Université Lorraine travaillent depuis 2006. De multiples démarches de validation et tests en entreprise ont été réalisés, ainsi qu’un bilan auprès des utilisateurs qui a été mené par un cabinet d’audit indépendant afin d’éviter un conflit d’intérêt avec les concepteurs. Le document porte sur la validation de la version 3, version qui capitalise les acquis des phases de validation antérieures

Labels constructively shape object categories in 10-month-old infants

How do infants' emerging language abilities affect their organization of objects into categories? The question of whether labels can shape the early perceptual categories formed by young infants has received considerable attention, but evidence has remained inconclusive. Here, 10-month-old infants (N = 80) were familiarized with a series of morphed stimuli along a continuum that can be seen as either one category or two categories. Infants formed one category when the stimuli were presented in silence or paired with the same label, but they divided the stimulus set into two categories when half of the stimuli were paired with one label and half with another label. Pairing the stimuli with two different nonlinguistic sounds did not lead to the same result. In this case, infants showed evidence for the formation of a single category, indicating that nonlinguistic sounds do not cause infants to divide a category. These results suggest that labels and visual perceptual information interact in category formation, with labels having the potential to constructively shape category structures already in preverbal infants, and that nonlinguistic sounds do not have the same effect

Labels direct infants’ attention to commonalities during novel category learning

Recent studies have provided evidence that labeling can influence the outcome of infants’ visual categorization. However, what exactly happens during learning remains unclear. Using eye-tracking, we examined infants’ attention to object parts during learning. Our analysis of looking behaviors during learning provide insights going beyond merely observing the learning outcome. Both labeling and non-labeling phrases facilitated category formation in 12-month-olds but not 8-month-olds (Experiment 1). Non-linguistic sounds did not produce this effect (Experiment 2). Detailed analyses of infants’ looking patterns during learning revealed that only infants who heard labels exhibited a rapid focus on the object part successive exemplars had in common. Although other linguistic stimuli may also be beneficial for learning, it is therefore concluded that labels have a unique impact on categorization