Learning from others is good, with others is better: the role of social interaction in human acquisition of new knowledge.

Learning in humans is highly embedded in social interaction: since the very early stages of our lives, we form memories and acquire knowledge about the world from and with others. Yet, within cognitive science and neuroscience, human learning is mainly studied in isolation. The focus of past research in learning has been either exclusively on the learner or (less often) on the teacher, with the primary aim of determining developmental trajectories and/or effective teaching techniques. In fact, social interaction has rarely been explicitly taken as a variable of interest, despite being the medium through which learning occurs, especially in development, but also in adulthood. Here, we review behavioural and neuroimaging research on social human learning, specifically focusing on cognitive models of how we acquire semantic knowledge from and with others, and include both developmental as well as adult work. We then identify potential cognitive mechanisms that support social learning, and their neural correlates. The aim is to outline key new directions for experiments investigating how knowledge is acquired in its ecological niche, i.e. socially, within the framework of the two-person neuroscience approach. This article is part of the theme issue 'Concepts in interaction: social engagement and inner experiences'.

The role of emotional valence in learning novel abstract concepts.

A recent study by Ponari, Norbury, and Vigliocco (2018), showed that emotional valence (i.e. whether a word evokes positive, negative, or no affect) predicts age-of-acquisition ratings and that up to the age of 8-9, children know abstract emotional words better than neutral ones. On the basis of these findings, emotional valence has been argued to provide a bootstrapping mechanism for the acquisition of abstract concepts. However, no previous work has directly assessed whether words' valence, or valence of the context in which words are used, facilitates learning of unknown abstract words. Here, we investigate whether valence supports acquisition of novel abstract concepts. Seven to 10 year old children were taught novel abstract words and concepts (words typically learned at an older age that the children did not know); words were either valenced (positive or negative) or neutral. We also manipulated the context in which words were presented: For 1 group of children, the teaching strategy emphasized emotional information; for the other, it emphasized encyclopedic, nonemotional information. Abstract words with emotional valence were learned better than neutral abstract words by children up to the age of 8-9, replicating previous findings; no effect of teaching strategy was found. These results indicate that emotional valence supports abstract concepts acquisition and further suggest that it is the valence information intrinsic to the word's meaning to have a role, rather than the valence of the context in which the word is learned. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Learning abstract words and concepts: insights from developmental language disorder.

Some explanations of abstract word learning suggest that these words are learnt primarily from the linguistic input, using statistical co-occurrences of words in language, whereas concrete words can also rely on non-linguistic, experiential information. According to this hypothesis, we expect that, if the learner is not able to fully exploit the information in the linguistic input, abstract words should be affected more than concrete ones. Embodied approaches instead argue that both abstract and concrete words can rely on experiential information and, therefore, there might not be any linguistic primacy. Here, we test the role of linguistic input in the development of abstract knowledge with children with developmental language disorder (DLD) and typically developing children aged 8-13. We show that DLD children, who by definition have impoverished language, do not show a disproportionate impairment for abstract words in lexical decision and definition tasks. These results indicate that linguistic information does not have a primary role in the learning of abstract concepts and words; rather, it would play a significant role in semantic development across all domains of knowledge.This article is part of the theme issue 'Varieties of abstract concepts: development, use and representation in the brain'.

Learning and Processing Abstract Words and Concepts: Insights From Typical and Atypical Development.

The paper describes two plausible hypotheses concerning the learning of abstract words and concepts. According to a first hypothesis, children would learn abstract words by extracting co-occurrences among words in linguistic input, using, for example, mechanisms as described by models of Distributional Semantics. According to a second hypothesis, children would exploit the fact that abstract words tend to have more emotional associations than concrete words to infer that they refer to internal/mental states. Each hypothesis makes specific predictions with regards to when and which abstract words are more likely to be learned; also they make different predictions concerning the impact of developmental disorders. We start by providing a review of work characterizing how abstract words and concepts are learned in development, especially between the ages of 6 and 12. Second, we review some work from our group that tests the two hypotheses above. This work investigates typically developing (TD) children and children with atypical development (developmental language disorders [DLD] and autism spectrum disorder [ASD] with and without language deficits). We conclude that the use of strategies based on emotional information, or on co-occurrences in language, may play a role at different developmental stages.

Acquisition of abstract concepts is influenced by emotional valence.

There is considerable lack of evidence concerning the linguistic and cognitive skills underpinning abstract vocabulary acquisition. The present study considers the role of emotional valence in providing an embodied learning experience in which to anchor abstract meanings. First, analyses of adult ratings of age-of-acquisition, concreteness and valence demonstrate that abstract words acquired early tend to be emotionally valenced. Second, auditory Lexical Decision accuracies of children aged 6-7, 8-9, and 10-11 years (n = 20 per group) complement these analyses, demonstrating that emotional valence facilitates processing of abstract words, but not concrete. These findings provide the first evidence that young, school-aged children are sensitive to emotional valence and that this facilitates acquisition of abstract words.

Processing advantage for emotional words in bilingual speakers.

Effects of emotion on word processing are well established in monolingual speakers. However, studies that have assessed whether affective features of words undergo the same processing in a native and nonnative language have provided mixed results: Studies that have found differences between native language (L1) and second language (L2) processing attributed the difference to the fact that L2 learned late in life would not be processed affectively, because affective associations are established during childhood. Other studies suggest that adult learners show similar effects of emotional features in L1 and L2. Differences in affective processing of L2 words can be linked to age and context of learning, proficiency, language dominance, and degree of similarity between L2 and L1. Here, in a lexical decision task on tightly matched negative, positive, and neutral words, highly proficient English speakers from typologically different L1s showed the same facilitation in processing emotionally valenced words as native English speakers, regardless of their L1, the age of English acquisition, or the frequency and context of English use.

How does emotional content affect lexical processing?

Even single words in isolation can evoke emotional reactions, but the mechanisms by which emotion is involved in automatic lexical processing are unclear. Previous studies using extremely similar materials and methods have yielded apparently incompatible patterns of results. In much previous work, however, words' emotional content is entangled with other non-emotional characteristics such as frequency of occurrence, familiarity and age of acquisition, all of which have potential consequences for lexical processing themselves. In the present study, the authors compare different models of emotion using the British Lexicon Project, a large-scale freely available lexical decision database. After controlling for the potentially confounding effects of non-emotional variables, a variety of statistical approaches revealed that emotional words, whether positive or negative, are processed faster than neutral words. This effect appears to be categorical rather than graded; is not modulated by emotional arousal; and is not limited to words explicitly referring to emotions. The authors suggest that emotional connotations facilitate processing due to the grounding of words' meanings in emotional experience.

Structural connectivity in a single case of progressive prosopagnosia: the role of the right inferior longitudinal fasciculus.

Progressive prosopagnosia (PP) is a clinical syndrome characterized by a progressive and selective inability to recognize and identify faces of familiar people. Here we report a patient (G.S.) with PP, mainly related to a prominent deficit in recognition of familiar faces, without a semantic (cross-modal) impairment. An in-depth evaluation showed that his deficit extended to other classes of objects, both living and non-living. A follow-up neuropsychological assessment did not reveal substantial changes after about 1 year. Structural MRI showed predominant right temporal lobe atrophy. Diffusion tensor imaging was performed to elucidate structural connectivity of the inferior longitudinal fasciculus (ILF) and the inferior fronto-occipital fasciculus (IFOF), the two major tracts that project through the core fusiform region to the anterior temporal and frontal cortices, respectively. Right ILF was markedly reduced in G.S., while left ILF and IFOFs were apparently preserved. These data are in favour of a crucial role of the neural circuit subserved by right ILF in the pathogenesis of PP.

Explicit recognition of emotional facial expressions is shaped by expertise: evidence from professional actors.

Can reading others' emotional states be shaped by expertise? We assessed processing of emotional facial expressions in professional actors trained either to voluntary activate mimicry to reproduce character's emotions (as foreseen by the "Mimic Method"), or to infer others' inner states from reading the emotional context (as foreseen by "Stanislavski Method"). In explicit recognition of facial expressions (Experiment 1), the two experimental groups differed from each other and from a control group with no acting experience: the Mimic group was more accurate, whereas the Stanislavski group was slower. Neither acting experience, instead, influenced implicit processing of emotional faces (Experiment 2). We argue that expertise can selectively influence explicit recognition of others' facial expressions, depending on the kind of "emotional expertise".

"Avoiding or approaching eyes"? Introversion/extraversion affects the gaze-cueing effect.

We investigated whether the extra-/introversion personality dimension can influence processing of others' eye gaze direction and emotional facial expression during a target detection task. On the basis of previous evidence showing that self-reported trait anxiety can affect gaze-cueing with emotional faces, we also verified whether trait anxiety can modulate the influence of intro-/extraversion on behavioral performance. Fearful, happy, angry or neutral faces, with either direct or averted gaze, were presented before the target appeared in spatial locations congruent or incongruent with stimuli's eye gaze direction. Results showed a significant influence of intra-/extraversion dimension on gaze-cueing effect for angry, happy, and neutral faces with averted gaze. Introverts did not show the gaze congruency effect when viewing angry expressions, but did so with happy and neutral faces; extraverts showed the opposite pattern. Importantly, the influence of intro-/extraversion on gaze-cueing was not mediated by trait anxiety. These findings demonstrated that personality differences can shape processing of interactions between relevant social signals.

Mapping correspondence between facial mimicry and emotion recognition in healthy subjects.

We aimed at verifying the hypothesis that facial mimicry is causally and selectively involved in emotion recognition. For this purpose, in Experiment 1, we explored the effect of tonic contraction of muscles in upper or lower half of participants' face on their ability to recognize emotional facial expressions. We found that the "lower" manipulation specifically impaired recognition of happiness and disgust, the "upper" manipulation impaired recognition of anger, while both manipulations affected recognition of fear; recognition of surprise and sadness were not affected by either blocking manipulations. In Experiment 2, we verified whether emotion recognition is hampered by stimuli in which an upper or lower half-face showing an emotional expression is combined with a neutral half-face. We found that the neutral lower half-face interfered with recognition of happiness and disgust, whereas the neutral upper half impaired recognition of anger; recognition of fear and sadness was impaired by both manipulations, whereas recognition of surprise was not affected by either manipulation. Taken together, the present findings support simulation models of emotion recognition and provide insight into the role of mimicry in comprehension of others' emotional facial expressions.

Impaired conscious recognition of negative facial expressions in patients with locked-in syndrome.

The involvement of facial mimicry in different aspects of human emotional processing is widely debated. However, little is known about relationships between voluntary activation of facial musculature and conscious recognition of facial expressions. To address this issue, we assessed severely motor-disabled patients with complete paralysis of voluntary facial movements due to lesions of the ventral pons [locked-in syndrome (LIS)]. Patients were required to recognize others' facial expressions and to rate their own emotional responses to presentation of affective scenes. LIS patients were selectively impaired in recognition of negative facial expressions, thus demonstrating that the voluntary activation of mimicry represents a high-level simulation mechanism crucially involved in explicit attribution of emotions.