Gestures are hand movements that naturally accompany speech and represent information. Decades of research show that incorporating gesture into instruction supports learning. But why does gesture help us learn? One possibility is that gesture provides a path to information that complements the path provided by speech. Researchers choose gestures for their studies that they think will provide meaningful information for learners. But no one has asked learners what they think of these gestures. We address this gap here. Children (N = 202; 8-10-year-olds) watched instructional videos teaching the concept of mathematical equivalence and answered questions about the purpose and content of the videos. They participated in either a gesture or action-onobjects condition. In both conditions, an instructor provided one strategy for solving math problems in her speech, and a second strategy using either gestures or actions-on-objects. Children also completed individual difference measures of math knowledge, general gesture processing, and working memory. We found that children were more likely to mention the strategy presented in the instructor's hands (and not her words) if they thought her goal was to teach when they were in the gesture condition, not the action condition. In addition, they increased the number of manually produced strategies they mentioned from trial 1 to 2 in the gesture condition, but not the action condition. No effects were influenced by our individual difference measures.

Co-speech gestures, which are spontaneous hand movements speakers produce when they talk, strongly enhance listeners’ cognitive processing of the spoken messages across development. Yet, the mechanisms by which gesture supports memory processing, particularly in interaction with speech, remain poorly understood, limiting the intentional use of gesture to improve learning outside of lab settings. Here, we ask whether certain gestures are consistently better remembered across people, independent of prior experience with the stimuli (the memorability effect), and if so, what semantic meaning and visual form features explain this effect. We created 360 10-second audiovisual stimuli by video recording 20 actors producing natural, unscripted speech and gestures while pretending to explain Piagetian liquid conservation to a child. Online participants completed a study–test memory task with video-only, audio-only, and audiovisual versions of the stimuli. Participants showed memory consistencies in all three conditions, and memorability for gesture+speech (audiovisual stimuli) was predicted by the memorability of both its gesture and speech components. We then quantified features of the gestural stimuli using 3 methods: trained coders, automatic computational analysis, and online crowdsourcing. Gestures are more memorable when they convey more information, and are most memorable when originally produced with memorable speech. Together, these findings reveal nuanced interactions between gesture and speech during memory processing, providing new insights into the memory mechanism underlying gesture’s benefits on learning and communications.

Teachers' hand movements during instruction can influence how children learn mathematics, but not all movements are equally effective. Gesture-based instruction on problems such as 4 + 2 + 5 = __ + 5-where the teacher places a V-shaped hand under the 4 and 2 and then points to the blank ("grouping strategy")-promotes learning better than action-based instruction-where the teacher manipulates magnetic numbers to mimic the gestures. How do hand movements facilitate learning? We tested 8- to 10-year-old children (n = 73) using functional near-infrared spectroscopy to measure neural activity as they watched gesture-based or action-based videotaped lessons. Gesture-based instruction elicited greater intersubject neural synchrony in motor cortex and angular gyrus, a region implicated in arithmetic processing. Critically, synchrony in the right angular gyrus during gesture instruction predicted learning gains, whereas synchrony during action-based instruction did not. Our work demonstrates how gestures foster shared representations in brain regions supporting arithmetic reasoning, offering a neural basis for gesture's behavioral advantages in mathematics education. These findings highlight functional near-infrared spectroscopy as a powerful tool for capturing how mathematical learning unfolds in children.

Speakers often play with their words in gradient ways (e.g., “It’s been a loooooooong day”). Signers too can alter their signs to capture gradient differences in meaning, but there are constraints on these modifications (Ferraro et al., 2025). Here, we ask whether these constraints are linguistically conditioned. We compare ASL signers to English-speakers asked to communicate silently using gesture. Both groups are given an ASL verb and asked to use it to describe a target event and three variants. We observe whether the target verb is gradiently modified to depict the variants. We found similarities between groups, suggesting these gradient modifications are gestural since gesturers, unfamiliar with ASL, can generate them. However, we also found differences, pointing to constraints on gradient modification that are linguistically conditioned. This phenomenon challenges traditional notions of language as a system in which linguistic rules do not apply to gradient phenomena.

Can number gestures solve the "gavagai" problem for children learning number words? In other words, does seeing a number gesture while hearing a number word focus children's attention on numeracy, as opposed to an infinite number of other possibilities? To find out, we conducted two studies: (1) a home-based study of 64 children, ages 14-30 months, observing natural interactions between parent and child; (2) a lab-based study of 112 children, ages 28-42 months, controlling for factors that varied freely in the observational study (e.g., the lab study was designed so that children could not "read" the correct answer off the experimenter's gesture). We found, in both home and lab studies, that adult number words with number gestures elicited child numeracy responses more often than adult number words alone. Interestingly, however, the child's number response was not always correct (particularly for large sets in the lab study). Children in both studies seemed to know that, when they saw a number gesture, a number response was called for--even if they did not know which number to respond with. Number gestures cue children into the fact that numeracy is the relevant dimension--akin to when a child knows a color response is needed but has no idea which color. Number gestures thus have the potential to focus attention on numeracy and ultimately foster number acquisition.

Using our hands to move a stick along a path differs in systematic ways from using our hands to communicate about moving the stick. Kinematic signatures (e.g., enlarged moving trajectories) have been found to mark a movement as communicative, relative to its non-communicative counterpart. But communicative movements are frequently embedded within an expressive system and might differ as a function of that system. For example, deaf signers move their hands when they communicate with sign language, which is a linguistic system. Hearing speakers also move their hands-they gesture along with speech-but those gestures do not form a linguistic system unto themselves. Do the communicative movements signers and speakers use to describe the same event differ as a function of the expressive systems within which they are embedded? Because some signs are highly iconic, researchers often assume that movements in these signs have the same properties as speakers' gestures. To test this assumption, we compared spontaneous hand gestures produced by hearing speakers when they talk (co-speech gesture) to productive iconic hand signs produced by deaf signers when the signs superficially resemble co-speech gestures (classifier signs). We used motion tracking and kinematic analyses to disentangle the spatial and temporal kinematic patterns of communicative movements in 33 English-speakers and 10 American Sign Language (ASL) signers, using each group's non-communicative movements as a control. Participants copied a movement on an object performed by a model (non-communicative movement) and then described what they did with the object (communicative movement). We found no differences between groups in how non-communicative movements related to communicative movements for spatial kinematics. However, for temporal kinematics, speakers' co-speech movements were less rhythmic and jerkier than their non-communicative movements, but signers' communicative movements were more rhythmic and smoother than their non-communicative movements. We thus found differences in the temporal aspects of co-speech gestures vs. classifier signs, leading to 3 conclusions: (i) Communicative movements do not always have the same kinematic signatures but depend on the expressive system within which they are embedded. (ii) Since signers' and speakers' communicative movements have different kinematic features, even highly iconic signed movements cannot be considered entirely gestural. (iii) We need fine-grained techniques to measure communicative movements, particularly when trying to identify the gestural aspects of sign. Communicative movements, even when superficially similar, differ as a function of the system they are part of.

Children who are exposed to minimal linguistic input can nevertheless introduce linguistic features into their communication systems at the level of morphology, syntax, and semantics (Goldin-Meadow, 2003a). However, it is not clear whether they can do so at the level of phonetics and phonology. This study asks whether congenitally deaf children, unable to learn spoken language and living in a hearing family without exposure to sign language, introduce phonology and phonetics into the gestural communication systems they create, called homesigns. We focused on two foundational properties of phonetics and phonology--discreteness of forms, which is defined independently of meaning and thus forms the basis of duality of patterning. We examined index finger and open flat handshapes in deaf children's homesigns and their hearing mothers' co-speech gestures. We found that handshapes in deictic gestures were more discrete in homesign than in co-speech gesture. Moreover, the degree of discreteness depended on meaning (emblems vs. deictics) in co-speech gesture, but not in homesign. Children can thus create discrete forms that are meaning-independent in their homesign systems even without a model for this feature. This finding helps explain why this feature of language is universal in spoken and signed languages.

How did the languages we use today come about? One way to make this problem more tractable is to think about language, not as a single entity but as a compilation of properties. Biological evolution may have resulted in the creation of some properties of language. However, cultural evolution, which relies on changes introduced by successive generations of users and is quicker than biological evolution, may also be responsible for the introduction of properties into language. Although it is difficult to distinguish linguistic properties introduced through biological evolution from those introduced through cultural evolution, one way to approach this problem is to observe a modern-day child who has not been exposed to a usable model for language. Despite the lack of a language model, a child in this situation can communicate and uses gestures to do so. These gestures, called homesigns, contain many, but not all, of the properties found in natural language. I suggest that the properties of language found in homesign are good candidates for linguistic properties that arose through biological evolution. By contrast, the properties not found in homesign are good candidates for linguistic properties that were introduced into language through cultural evolution. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Children learning structurally different languages display variability in the way they package semantic elements of a physical motion event in gesture, mirroring the patterns found in speech for the same events. In this study, we ask whether these differences extend to metaphorical motion events and, if so, when in development the patterns become evident. We studied the speech and gestures produced by 100 children learning English or Turkish (n = 50/language)-equally divided into 5 age groups: 3-4, 5-6, 7-8, 9-10, 11-12 years-when describing metaphorical motion events (e.g., idea runs out of the mind). We compared the patterns to previously reported findings on the same children describing physical motion (e.g., girl runs out of the house). Our results showed evidence for cross-linguistic differences in the expression of metaphorical motion events in both speech and gesture, akin to cross-linguistic differences observed in the expression of physical motion events. But language-specific patterns emerged later in metaphorical than in physical motion descriptions, both in speech and in co-speech gesture. Our results suggest that gesture and speech form tightly integrated systems in the expression of metaphorical concepts, as they do for the expression of physical events, by children learning structurally different languages.

A growing body of research suggests that children's use and understanding of cardinal number gestures (e.g., raising two fingers to indicate "two") reflect greater cardinal number knowledge than their number words alone (e.g., Butts, 2025; Gibson et al., 2019, 2022; Gunderson et al., 2015; Orrantia et al., 2024; Oswald et al., 2025). The present study adds to these findings by examining how often, and in what contexts, parents and their young children use iconic number gestures, with a particular focus on how these gestures are used in relation to number words. In a naturalistic, at-home longitudinal study, we found that 14- to 58-month-old children and their parents used iconic number gestures far less often than number words. Parents used more number words than the children, but children used more number gestures than the parents. Both children and parents used number gestures more often for nonpresent entities than for present entities, even though they both displayed the opposite pattern for number words (i.e., more number words for present than nonpresent entities). Finally, children were more likely to use number gestures if their parents used them (some parents never used number gestures during the observations), but neither parents' nor children's use of number gestures early on predicted children's cardinal number knowledge at 46 months of age. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Language is traditionally characterized as an arbitrary, symbolic system, made up of discrete, categorical forms. But iconicity and gradience are pervasive in communication. For example, in spoken languages, word forms can be "played with" in iconic gradient ways by varying vowel length, pitch, or speed (e.g., "It's been a loooooooong day"). However, little is known about this process in sign languages. Here, we (1) explore gradient modification in three dimensions of motion in American Sign Language (ASL), and (2) ask whether the three dimensions are equally likely to be modified. We asked deaf signers of ASL (n = 11, mean age = 49.3) to describe an event manipulated along speed, direction, or path, and observed their use of gradient modification in lexical and depicting signs. We found that signers alter the forms of both types of signs to enhance meaning. However, the three motion dimensions were not modified equally in lexical signs, suggesting constraints on gradient modification. These constraints may be linguistic in nature, found only in signers. Alternatively, the constraints could reflect difficulties in using the hands to convey particular modifications and, if so, should be found in speakers as well as signers.

This paper examines whether observers use gestural information to decide the meaning of the polysemous verb touch in ambiguous contexts. To address this question, three studies were carried out. Study 1 tests whether observers could accurately distinguish the meaning of the verb touch just by looking at hand gestures. Study 2 explores which gesture location and handshape combinations are associated with the physical and emotional meanings of touch. Study 3 investigates whether observers decide the meaning of touch faster when they see a co-speech hand gesture and whether reaction time varies depending on the specific gesture combination observed. The main findings illustrate how the modality of gesture helps observers to disambiguate the meaning of a polysemous word such as the verb touch. Thus, this research shows that location and handshape are key components that bias the meaning of touch when the verbal message is ambiguous or absent.

Instrumental movements are kinematically different from communicative movements. Kinematics differ when we use our hands to hammer a nail vs. using them to describe hammering a nail. Here, we ask whether communicative movements all share the same kinematic profiles and thus differ from instrumental movements in the same way. We compared spontaneous gestures produced by hearing speakers when they talk (co-speech gesture) to productive iconic signs produced by deaf signers when the signs superficially resemble co-speech gestures (classifier signs). We used motion tracking and kinematic analyses to disentangle the spatial and temporal kinematic patterns of communicative movements in 33 English-speakers and 10 American Sign Language (ASL) signers, using each group’s instrumental movements as a control. Participants copied a movement on an object performed by a model (instrumental movement) and then described what they did with the object (communicative movement). We found no instrumental-communicative differences between groups in spatial kinematics. However, for temporal kinematics, speakers’ co-speech movements were less rhythmic and jerkier than their instrumental movements; in contrast, signers’ communicative movements were more rhythmic and smoother than their instrumental movements. We thus found differences in the temporal (but not spatial) kinematic signatures of co-speech gestures vs. classifier signs, leading to 3 conclusions: (i) communicative movements do not always have the same kinematic signatures; (ii) since signers’ and speakers’ communicative movements have different kinematic features, even highly iconic signed movements cannot be considered entirely gestural; and (iii) we need fine-grained techniques to measure movement components when identifying the gestural aspects of sign.

One reason that Black and White individuals often have difficulties in their interactions may stem from differences in nonverbal communication styles (Bishop, 1979; Crago et al., 1997; J. N. Shelton et al., 2023; Varonis & Gass, 1985). Here, across four studies, we examine cultural differences in gesture, a form of nonverbal communication, in Black and White speakers. In Study 1, Black participants (N = 75) rated actors who gestured more as being more natural and White participants (N = 75) rated actors who gestured less as being more natural. In addition, Black actors were rated as being more natural when gesturing more, while White actors were rated as being more natural when gesturing less. Study 2 shows that when a Black talk show host speaks with a Black guest, he gestures more than when speaking with a White guest. Study 3 found that Black speakers (N = 25) gestured more frequently and used larger gestures compared to White speakers (N = 25). Finally, Study 4 demonstrates that Biracial Black/White speakers who had their Black identity primed (N = 32) gestured more frequently and used larger gestures than those who had their White identity primed (N = 22), suggesting that gesture is culturally tied to racial identity salience. Together, these studies suggest that there are culturally learned gesture styles based on racial group membership. Thus, gesture is an understudied aspect of interracial interactions that may influence comfort in cross-cultural communication between Black and White individuals. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

Despite increased attempts to express equality in speech, biases often leak out through subtle linguistic cues. For example, the subject-complement statement (SCS, "Girls are as good as boys at math") is used to advocate for equality but often reinforces gender stereotypes (boys are the standard against which girls are judged). We ask whether stereotypes conveyed by SCS can be counteracted by gesture. Two preregistered studies with 8- to 11- y- old children (N = 320 total) investigate whether an equal gesture-two palms placed at the same height-mitigates the gender stereotype induced by SCS. Children who saw the equal gesture along with SCS were more likely to express egalitarian beliefs than children who saw no gesture or an unequal gesture. Children can extract meaning from gesture when making stereotypical inferences, suggesting that the equal gesture may prove to be an innovative, and simple, intervention to counteract stereotypes introduced by subtle language.

Explaining the origins of language is a key challenge in understanding ourselves as a species. We present an empirical framework that draws on synergies across fields to facilitate robust studies of language evolution. The approach is multifaceted, seeing language emergence as dependent on the convergence of multiple capacities, each with their own evolutionary trajectories. It is explicitly biocultural, recognizing and incorporating the importance of both biological preparedness and cultural transmission as well as interactions between them. We demonstrate this approach through three case studies that examine the evolution of different facets involved in human language (vocal production learning, linguistic structure, and social underpinnings).

Language is a productive system--we routinely produce well- formed utterances that we have never heard before. It is, however, difficult to assess when children first achieve linguistic productivity simply because we rarely know all the utterances a child has experienced. The onset of linguistic productivity has been at the heart of a long- standing theoretical question in language acquisition--do children come to language learning with abstract categories that they deploy from the earliest moments of acquisition? We address the problem of when linguistic productivity begins by marrying longitudinal behavioral observations and computational modeling to capitalize on the strengths of each. We used behavioral data to assess when a sample of 64 English- learning children began to productively combine determiners and nouns, a linguistic construction previously used to address this theoretical question. After the onset of productivity, the children produced determiner-noun combinations that were not attested in our sample of their linguistic input from caregivers. We used computational techniques to model the onsets and trajectories of determiner-noun combinations in these 64 children, as well as characteristics of their utterances in which the determiner was omitted. Because we knew exactly what input the model was trained on, we could, with confidence, know that the model had gone beyond its input. The parallels found between child and model in the timing and number of novel combinations suggest that the children too were creatively going beyond their input.

Our hands are always with us and are used for communication all over the world. When children do not have an established language model to learn from, they use their hands to gesture, and these gestures take on the forms of language. In this role, the hands reveal the fundamental properties of the mind that give shape to language. When children do learn an established language, they again use their hands to gesture. These gestures do not look like language but form an integrated system with language. In this role, the hands can convey ideas not found in the language they accompany. In both contexts, gesture provides a clear view of the mind hidden in our hands.