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1.
J Infect Dev Ctries ; 18(3): 362-370, 2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38635617

RESUMO

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is caused by the SARS-CoV-2 virus. It has impacted millions of individuals and caused numerous casualties. Consequently, there was a race to develop vaccines against the virus. However, there has been unequal vaccine distribution among nations, and concerns over side effects have resulted in vaccine hesitancy, reducing vaccination rates in many countries and hindering pandemic eradication. Preventive measures like well-fitted masks, frequent hand washing, alcohol-based sanitizers, and maintaining physical distance remain crucial to curb SARS-CoV-2 transmission. This study examined the adoption of these preventive measures among sellers in the Beni Mellal region of Morocco. RESULTS: We analyzed a cohort of 700 merchants, including 40.28% middle-aged males. Among them, 53% (371/700) wore masks, with 61.08% using medical masks, and 44.05% correctly positioned their masks. Additionally, 20.29% (142/700) carried disinfectants, of whom 117 used them at least once in 30 minutes. However, physical distancing was lacking in 78.29% of sellers, particularly among young and middle-aged males (18% and 31.86%, respectively). More than 80% of the vendors had frequent physical contact with others, primarily through hands. Surprisingly, only 1% (7/700) of participants combined the following preventive measures: using a disinfectant at least once, wearing a well-fitted mask, practicing physical distancing, and avoiding contact with others. Two individuals (0.29%) refrained from touching any surfaces. Money accounted for 76.57% of commonly touched surfaces; yet only 0.29% adhered to the preventive measures while handling money. Furthermore, a majority of individuals (92.14%, 645/700) were observed touching their faces at least once.


Assuntos
COVID-19 , Desinfetantes , Masculino , Pessoa de Meia-Idade , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , SARS-CoV-2 , Marrocos/epidemiologia , Máscaras , Pandemias/prevenção & controle
2.
Data Brief ; 54: 110299, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38524840

RESUMO

The dataset includes thermal videos of various hand gestures captured by the FLIR Lepton Thermal Camera. A large dataset is created to accurately classify hand gestures captured from eleven different individuals. The dataset consists of 9 classes corresponding to various hand gestures from different people collected at different time instances with complex backgrounds. This data includes flat/leftward, flat/rightward, flat/contract, spread/ leftward, spread/rightward, spread/contract, V-shape/leftward, V-shape/rightward, and V-shape/contract. There are 110 videos in the dataset for each gesture and a total of 990 videos corresponding to 9 gestures. Each video has data of three different (15/10/5) frame lengths.

3.
Res Dev Disabil ; 148: 104711, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38520885

RESUMO

BACKGROUND: Studies on late talkers (LTs) highlighted their heterogeneity and the relevance of describing different communicative profiles. AIMS: To examine lexical skills and gesture use in expressive (E-LTs) vs. receptive-expressive (R/E-LTs) LTs through a structured task. METHODS AND PROCEDURES: Forty-six 30-month-old screened LTs were distinguished into E-LTs (n= 35) and R/E-LTs (n= 11) according to their receptive skills. Lexical skills and gesture use were assessed with a Picture Naming Game by coding answer accuracy (correct, incorrect, no response), modality of expression (spoken, spoken-gestural, gestural), type of gestures (deictic, representational), and spoken-gestural answers' semantic relationship (complementary, equivalent, supplementary). OUTCOMES AND RESULTS: R/E-LTs showed lower scores than E-LTs for noun and predicate comprehension with fewer correct answers, and production with fewer correct and incorrect answers, and more no responses. R/E-LTs also exhibited lower scores in spoken answers, representational gestures, and equivalent spoken-gestural answers for noun production and in all spoken and gestural answers for predicate production. CONCLUSIONS AND IMPLICATIONS: Findings highlighted more impaired receptive and expressive lexical skills and lower gesture use in R/E-LTs compared to E-LTs, underlying the relevance of assessing both lexical and gestural skills through a structured task, besides parental questionnaires and developmental scales, to describe LTs' communicative profiles.


Assuntos
Gestos , Transtornos do Desenvolvimento da Linguagem , Humanos , Compreensão/fisiologia , Pais , Testes de Linguagem , Vocabulário
4.
Top Cogn Sci ; 2024 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-38493475

RESUMO

Language is inherently multimodal. In spoken languages, combined spoken and visual signals (e.g., co-speech gestures) are an integral part of linguistic structure and language representation. This requires an extension of the parallel architecture, which needs to include the visual signals concomitant to speech. We present the evidence for the multimodality of language. In addition, we propose that distributional semantics might provide a format for integrating speech and co-speech gestures in a common semantic representation.

5.
Anim Cogn ; 27(1): 18, 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38429467

RESUMO

Gestures play a central role in the communication systems of several animal families, including primates. In this study, we provide a first assessment of the gestural systems of a Platyrrhine species, Geoffroy's spider monkeys (Ateles geoffroyi). We observed a wild group of 52 spider monkeys and assessed the distribution of visual and tactile gestures in the group, the size of individual repertoires and the intentionality and effectiveness of individuals' gestural production. Our results showed that younger spider monkeys were more likely than older ones to use tactile gestures. In contrast, we found no inter-individual differences in the probability of producing visual gestures. Repertoire size did not vary with age, but the probability of accounting for recipients' attentional state was higher for older monkeys than for younger ones, especially for gestures in the visual modality. Using vocalizations right before the gesture increased the probability of gesturing towards attentive recipients and of receiving a response, although age had no effect on the probability of gestures being responded. Overall, our study provides first evidence of gestural production in a Platyrrhine species, and confirms this taxon as a valid candidate for research on animal communication.


Assuntos
Ateles geoffroyi , Atelinae , Humanos , Animais , Gestos , Comunicação Animal , Individualidade
6.
Neuropsychol Rev ; 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38448754

RESUMO

Researchers and clinicians have long used meaningful intransitive (i.e., not tool-related; MFI) gestures to assess apraxia-a complex and frequent motor-cognitive disorder. Nevertheless, the neurocognitive bases of these gestures remain incompletely understood. Models of apraxia have assumed that meaningful intransitive gestures depend on either long-term memory (i.e., semantic memory and action lexicons) stored in the left hemisphere, or social cognition and the right hemisphere. This meta-analysis of 42 studies reports the performance of 2659 patients with either left or right hemisphere damage in tests of meaningful intransitive gestures, as compared to other gestures (i.e., MFT or meaningful transitive and MLI or meaningless intransitive) and cognitive tests. The key findings are as follows: (1) deficits of meaningful intransitive gestures are more frequent and severe after left than right hemisphere lesions, but they have been reported in both groups; (2) we found a transitivity effect in patients with lesions of the left hemisphere (i.e., meaningful transitive gestures more difficult than meaningful intransitive gestures) but a "reverse" transitivity effect in patients with lesions of the right hemisphere (i.e., meaningful transitive gestures easier than meaningful intransitive gestures); (3) there is a strong association between meaningful intransitive and transitive (but not meaningless) gestures; (4) isolated deficits of meaningful intransitive gestures are more frequent in cases with right than left hemisphere lesions; (5) these deficits may occur in the absence of language and semantic memory impairments; (6) meaningful intransitive gesture performance seems to vary according to the emotional content of gestures (i.e., body-centered gestures and emotional valence-intensity). These findings are partially consistent with the social cognition hypothesis. Methodological recommendations are given for future studies.

7.
PeerJ ; 12: e16800, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38406280

RESUMO

Using field observations from a sanctuary, Oña and colleagues (DOI: 10.7717/peerj.7623) investigated the semantics of face-gesture combinations in chimpanzees (Pan troglodytes). The response of the animals to these signals was encoded as a binary measure: positive interactions such as approaching or grooming were considered affiliative; ignoring or attacking was considered non-affiliative. The relevant signals are illustrated in Fig. 1 (https://doi.org/10.7717/peerj.7623/fig-1), together with the outcome in terms of average affiliativeness. The authors observe that there seems to be no systematicity in the way the faces modify the responses to the gestures, sometimes reducing affiliativeness, sometimes increasing it. A strong interpretation of this result would be that the meaning of a gesture-face combination cannot be derived from the meaning of the gesture and the meaning of the face, that is, the interpretation of chimpanzees' face-gesture combinations are non compositional in nature. We will revisit this conclusion: we will exhibit simple compositional systems which, after all, may be plausible. At the methodological level, we argue that it is critical to lay out the theoretical options explicitly for a complete comparison of their pros and cons.


Assuntos
Hominidae , Pan troglodytes , Animais , Pan troglodytes/fisiologia , Gestos , Semântica
8.
Anat Sci Educ ; 17(3): 462-467, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38351605

RESUMO

The ability to create efficient "mental models" or representations of anatomical structures is crucial for achieving competence in most areas of anatomy. Gesture-based teaching has been recognized to lighten cognitive loads and allow superior mental model creation compared to non-gestural teaching practices. This commentary explores the cognitive basis and possible mechanisms behind this advantage such as (1) reducing visual working memory load, (2) allowing parallel and sequential development of internal representations, and (3) facilitating preferential feature extraction and improved organization of spatial information. We also highlight how information transfer limitations of the gestural medium, interestingly, unveil features and organizational motifs preserved in the "expert's" mental schemas concerning particular anatomical structures. The universal and innate use of gestures in communication, their visual nature, and the ability to break down complex spatial information through sequential steps, all add to the immense potential of this subtle yet powerful tool of hand gestures. As pedagogical practices in the anatomical sciences continue to evolve largely towards technology-enhanced teaching utilizing perceptually richer media, the unique advantages of gesture-based teaching need to be reemphasized.


Assuntos
Anatomia , Gestos , Anatomia/educação , Aprendizagem , Cognição , Memória de Curto Prazo
9.
Bioengineering (Basel) ; 11(2)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38391594

RESUMO

Prosthetic technology has witnessed remarkable advancements, yet challenges persist in achieving autonomous grasping control while ensuring the user's experience is not compromised. Current electronic prosthetics often require extensive training for users to gain fine motor control over the prosthetic fingers, hindering their usability and acceptance. To address this challenge and improve the autonomy of prosthetics, this paper proposes an automated method that leverages computer vision-based techniques and machine learning algorithms. In this study, three reinforcement learning algorithms, namely Soft Actor-Critic (SAC), Deep Q-Network (DQN), and Proximal Policy Optimization (PPO), are employed to train agents for automated grasping tasks. The results indicate that the SAC algorithm achieves the highest success rate of 99% among the three algorithms at just under 200,000 timesteps. This research also shows that an object's physical characteristics can affect the agent's ability to learn an optimal policy. Moreover, the findings highlight the potential of the SAC algorithm in developing intelligent prosthetic hands with automatic object-gripping capabilities.

10.
J Child Lang ; : 1-25, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38314574

RESUMO

Based on the linguistic analysis of game explanations and retellings, the paper's goal is to investigate the relation of preschool children's situated discourse competence and iconic gestures in different communicative genres, focussing on reinforcing and supplementary speech-gesture-combinations. To this end, a method was developed to evaluate discourse competence as a context-sensitive and interactively embedded phenomenon. The so-called GLOBE-model was adapted to assess discourse competence in relation to interactive scaffolding. The findings show clear links between the children's competence and their parents' scaffolding. We suggest this to be evidence of a fine-tuned interactive support system. The results also indicate strong relations between higher discourse competence and increased frequency of iconic gestures. This applies in particular to reinforcing gestures. The results are interpreted as a confirmation that the speech-gesture system undergoes systematic changes during early childhood, and that gesturing becomes more iconic - and thus more communicative - when discourse competence is growing.

11.
J Robot Surg ; 18(1): 47, 2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38244130

RESUMO

To collect validity evidence for the assessment of surgical competence through the classification of general surgical gestures for a simulated robot-assisted radical prostatectomy (RARP). We used 165 video recordings of novice and experienced RARP surgeons performing three parts of the RARP procedure on the RobotiX Mentor. We annotated the surgical tasks with different surgical gestures: dissection, hemostatic control, application of clips, needle handling, and suturing. The gestures were analyzed using idle time (periods with minimal instrument movements) and active time (whenever a surgical gesture was annotated). The distribution of surgical gestures was described using a one-dimensional heat map, snail tracks. All surgeons had a similar percentage of idle time but novices had longer phases of idle time (mean time: 21 vs. 15 s, p < 0.001). Novices used a higher total number of surgical gestures (number of phases: 45 vs. 35, p < 0.001) and each phase was longer compared with those of the experienced surgeons (mean time: 10 vs. 8 s, p < 0.001). There was a different pattern of gestures between novices and experienced surgeons as seen by a different distribution of the phases. General surgical gestures can be used to assess surgical competence in simulated RARP and can be displayed as a visual tool to show how performance is improving. The established pass/fail level may be used to ensure the competence of the residents before proceeding with supervised real-life surgery. The next step is to investigate if the developed tool can optimize automated feedback during simulator training.


Assuntos
Procedimentos Cirúrgicos Robóticos , Masculino , Humanos , Procedimentos Cirúrgicos Robóticos/métodos , Gestos , Competência Clínica , Próstata , Prostatectomia/métodos
12.
JMIR Hum Factors ; 11: e45494, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38277201

RESUMO

BACKGROUND: Social robots are becoming increasingly important as companions in our daily lives. Consequently, humans expect to interact with them using the same mental models applied to human-human interactions, including the use of cospeech gestures. Research efforts have been devoted to understanding users' needs and developing robot's behavioral models that can perceive the user state and properly plan a reaction. Despite the efforts made, some challenges regarding the effect of robot embodiment and behavior in the perception of emotions remain open. OBJECTIVE: The aim of this study is dual. First, it aims to assess the role of the robot's cospeech gestures and embodiment in the user's perceived emotions in terms of valence (stimulus pleasantness), arousal (intensity of evoked emotion), and dominance (degree of control exerted by the stimulus). Second, it aims to evaluate the robot's accuracy in identifying positive, negative, and neutral emotions displayed by interacting humans using 3 supervised machine learning algorithms: support vector machine, random forest, and K-nearest neighbor. METHODS: Pepper robot was used to elicit the 3 emotions in humans using a set of 60 images retrieved from a standardized database. In particular, 2 experimental conditions for emotion elicitation were performed with Pepper robot: with a static behavior or with a robot that expresses coherent (COH) cospeech behavior. Furthermore, to evaluate the role of the robot embodiment, the third elicitation was performed by asking the participant to interact with a PC, where a graphical interface showed the same images. Each participant was requested to undergo only 1 of the 3 experimental conditions. RESULTS: A total of 60 participants were recruited for this study, 20 for each experimental condition for a total of 3600 interactions. The results showed significant differences (P<.05) in valence, arousal, and dominance when stimulated with the Pepper robot behaving COH with respect to the PC condition, thus underlying the importance of the robot's nonverbal communication and embodiment. A higher valence score was obtained for the elicitation of the robot (COH and robot with static behavior) with respect to the PC. For emotion recognition, the K-nearest neighbor classifiers achieved the best accuracy results. In particular, the COH modality achieved the highest level of accuracy (0.97) when compared with the static behavior and PC elicitations (0.88 and 0.94, respectively). CONCLUSIONS: The results suggest that the use of multimodal communication channels, such as cospeech and visual channels, as in the COH modality, may improve the recognition accuracy of the user's emotional state and can reinforce the perceived emotion. Future studies should investigate the effect of age, culture, and cognitive profile on the emotion perception and recognition going beyond the limitation of this work.


Assuntos
Robótica , Humanos , Emoções , Comunicação não Verbal , Gestos , Percepção
13.
Artigo em Inglês | MEDLINE | ID: mdl-38270620

RESUMO

Temporal coordination of communicative behavior is not only located between but also within interaction partners (e.g., gaze and gestures). This intrapersonal synchrony (IaPS) is assumed to constitute interpersonal alignment. Studies show systematic variations in IaPS in individuals with autism, which may affect the degree of interpersonal temporal coordination. In the current study, we reversed the approach and mapped the measured nonverbal behavior of interactants with and without ASD from a previous study onto virtual characters to study the effects of the differential IaPS on observers (N = 68), both with and without ASD (crossed design). During a communication task with both characters, who indicated targets with gaze and delayed pointing gestures, we measured response times, gaze behavior, and post hoc impression formation. Results show that character behavior indicative of ASD resulted in overall enlarged decoding times in observers and this effect was even pronounced in observers with ASD. A classification of observer's gaze types indicated differentiated decoding strategies. Whereas non-autistic observers presented with a rather consistent eyes-focused strategy associated with efficient and fast responses, observers with ASD presented with highly variable decoding strategies. In contrast to communication efficiency, impression formation was not influenced by IaPS. The results underline the importance of timing differences in both production and perception processes during multimodal nonverbal communication in interactants with and without ASD. In essence, the current findings locate the manifestation of reduced reciprocity in autism not merely in the person, but in the interactional dynamics of dyads.

14.
Q J Exp Psychol (Hove) ; 77(2): 257-277, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36890437

RESUMO

This study examined whether the metacognitive system monitors the potential positive effects of gestures on spatial thinking. Participants (N = 59, 31F, Mage = 21.67) performed a mental rotation task, consisting of 24 problems varying in difficulty, and they evaluated their confidence in their answers to problems in either gesture or control conditions. The results revealed that performance and confidence were higher in the gesture condition, in which the participants were asked to use their gestures during problem-solving, compared with the control condition, extending the literature by evidencing gestures' role in metacognition. Yet, the effect was only evident for females, who already performed worse than males, and when the problems were difficult. Encouraging gestures adversely affected performance and confidence in males. Such results suggest that gestures selectively influence cognition and metacognition and highlight the importance of task-related (i.e., difficulty) and individual-related variables (i.e., sex) in elucidating the links between gestures, confidence, and spatial thinking.


Assuntos
Gestos , Metacognição , Masculino , Feminino , Humanos , Adulto Jovem , Adulto , Resolução de Problemas , Cognição , Mãos
15.
J Hum Kinet ; 89: 5-18, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38053963

RESUMO

Fluency is a movement parameter combining smoothness and hesitation, and its objective measurement may be used to determine the effects of practice on sports performance. This study aimed to measure fluency in parkour, an acrobatic discipline comprising complex non-cyclical movements, which involves fluency as a critical aspect of performance. Inter-individual fluidity differences between advanced and novice athletes as well as intra-individual variations of fluency between different parts and subsequent repetitions of a path were addressed. Seventeen parkour participants were enrolled and divided into two groups based on their experience. We analysed signals captured from an inertial measurement unit fixed on the back of the pelvis of each participant during three consecutive repetitions of a specifically designed parkour routine under the guidance of video analysis. Two fluency parameters, namely smoothness and hesitation, were measured. Smoothness was calculated as the number of inflexions on the so-called jerk graph; hesitation was the percentage of the drop in the centre of mass velocity. Smoothness resulted in significantly lower values in advanced athletes (mean: 126.4; range: 36-192) than in beginners (mean: 179.37; range: 98-272) during one of the three motor activities (p = 0.02). A qualitative analysis of hesitation showed that beginner athletes tended to experience more prominent velocity drops and negative deflection than more advanced athletes. In conclusion, a system based on a video and an inertial measurement unit is a promising approach for quantification and the assessment of variability of fluency, and it is potentially beneficial to guide and evaluate the training process.

16.
Brain Sci ; 13(12)2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38137160

RESUMO

This paper investigates the influence of gestures on foreign language (FL) vocabulary learning. In this work, we first address the state of the art in the field and then delve into the research conducted in our lab (three experiments already published) in order to finally offer a unified theoretical interpretation of the role of gestures in FL vocabulary learning. In Experiments 1 and 2, we examined the impact of gestures on noun and verb learning. The results revealed that participants exhibited better learning outcomes when FL words were accompanied by congruent gestures compared to those from the no-gesture condition. Conversely, when meaningless or incongruent gestures were presented alongside new FL words, gestures had a detrimental effect on the learning process. Secondly, we addressed the question of whether or not individuals need to physically perform the gestures themselves to observe the effects of gestures on vocabulary learning (Experiment 3). Results indicated that congruent gestures improved FL word recall when learners only observed the instructor's gestures ("see" group) and when they mimicked them ("do" group). Importantly, the adverse effect associated with incongruent gestures was reduced in the "do" compared to that in the "see" experimental group. These findings suggest that iconic gestures can serve as an effective tool for learning vocabulary in an FL, particularly when the gestures align with the meaning of the words. Furthermore, the active performance of gestures helps counteract the negative effects associated with inconsistencies between gestures and word meanings. Consequently, if a choice must be made, an FL learning strategy in which learners acquire words while making gestures congruent with their meaning would be highly desirable.

17.
Appl Neuropsychol Child ; : 1-21, 2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37855408

RESUMO

Linguistic precursors (gaze, joint attention, gestures, social interaction, etc.) have a predictive value over the course of child development. The aim of the present review is to analyze the content structure, and the theoretical perspective, of assessment instruments that focus on linguistic precursors for the 6-18-month age group. The search was achieved through the following citation databases: BVS, MEDLINE/PubMed, Web of Science, SciELO, Redalyc, Web of Science, Google Scholar, as well as the American Speech-Language-Hearing Association (ASHA). Elegible articles were obtained using the following terms: "neuropsychological tests," "nonverbal communication," "child language" and "infant" as well as their equivalents in Spanish and Portuguese. Twenty-six assessment instruments were found to be compatible with the eligibility criteria. From the results, 19 instruments explore various domains of linguistic precursors, while 7 are task-specific proposals. Five instruments are aimed at early detection of signs of Autistic Spectrum Disorder. The implementation of Bruner's model of communicative functions was found on 15% of the instruments. This article provides timely information for clinicians who work with children during early stages of development, in relation to the methodical monitoring, assessment and accompaniment of infants and toddlers during the prelinguistic stage.

18.
Stud Health Technol Inform ; 309: 58-62, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37869806

RESUMO

Hand and joint mobility recovery involve performing a set of exercises. Gestures are often used in the hand mobility recovery process. This paper discusses the selection and the use of 2 models of neural networks for the classification of data that describe Leap Motion gestures. The gestures are: the hand opening and closing gesture and the palm rotation gesture. The purpose is the optimal selection of the neural network model to be used in the classification of the data describing the recovery gestures. The models chosen for the classification of the two gestures were: Linear Discriminant Analysis (LDA) and K-neighbors Classifier (KNN). The accuracies achieved in the classification of the gestures for each model are: 0.91 - LDA and 0.98 - KNN.


Assuntos
Gestos , Mãos , Análise Discriminante , Redes Neurais de Computação , Rotação , Algoritmos
19.
Med Sci Educ ; 33(5): 1035-1037, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37886266

RESUMO

Neuroanatomy ranks highly among the most difficult topics to master in medical school. We describe two gesture-based techniques aimed at simplifying the anatomy of two complex intracranial nervous structures: the trigeminal nerve and the cerebral fornix.

20.
J Intell ; 11(10)2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37888424

RESUMO

Complex and often unobservable STEM constructs and processes are represented using a variety of representations, including iconic gestures in which the body is configured or moved to resemble a referent's spatial properties or actions. Earlier researchers have suggested links between gesturing and expertise, leading some to recommend instructional gestures. Earlier research, however, has been largely correlational; furthermore, some gestures may be made with misleading positions or movements. Using the illustrative topic of strike in structural geology, we investigated the existence and impact of inaccurate instructional gestures. In Study 1, we examined videotapes of participants who had been asked to explain strikes to another person. We observed inaccurate (non-horizontal) strike gestures not only among novices (first introduced to strike during the study itself, n = 68) but also among participants who had greater expertise in geology (n = 21). In Study 2, we randomly assigned novices (N = 167) to watch video lessons in which the instructor accompanied verbal explanations of strikes with accurate, inaccurate, or no iconic gestures and tested students' learning on a strike-mapping task. Students with low spatial-perception skills showed no impact of their gestural condition on performance. Students with high spatial-perception skills showed no advantage from accurate gestures but performed significantly worse in the inaccurate-gesture condition. Findings suggest that recommendations to use gestures during instruction should include professional development programs that reduce the occurrence of inaccurate gestures.

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