cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.17910/b7h592
title: Ledge and wedge: Younger and older adults' perception of action possibilities

description: Younger (college age) and older adults (65 years or older) decided whether they could squeeze sideways through narrow doorways and inch sideways along narrow ledges while walking over a raised platform. Doorways and ledges varied in width from 0 to 64 cm. Doorway and ledge widths were presented with a psychophysical staircase procedure and each participant received ~ 33 trials per condition. Participants' behaviors were recorded from overhead frontal and side views; doorway and ledge widths were also recorded. At the end of each session, participants' body size was measured in the doorway.
DOI: 10.17910/b77p4v
title: Children's social and motor play on a playground

description: Two pre-adolescent girls engaged in social and gross motor free play on a public playground. The girls were instructed to show the camera operators the various ways in which they play. They used monkey bars, fences, ledges, trees, swings, climbers, and other equipment in ways that were not the likely uses intended by the playground designers. The girls were filmed from two camera views. Other children and parents entered and left the scene.
DOI: 10.17910/b73w2x
title: Numerical Cognition Without Words: Evidence from Amazonia

description: Several videos depict Pirahã children and adults engaging in everyday activities. There are also depictions of pilot experimental tasks. Most of these are not the actual data collections reported in Gordon (2004). However, some of the videos depict elicitations of numerical quantities by Keren Everett, and these are included in the Supplementary Online Materials in Gordon (2004) and are briefly described in the paper. Abstract from Gordon (2004): Members of the Piraha˜ tribe use a ‘‘one-two-many’’ system of counting. I ask whether speakers of this innumerate language can appreciate larger numerosities without the benefit of words to encode them. This addresses the classic Whorfian question about whether language can determine thought. Results of numerical tasks with varying cognitive demands show that numerical cognition is clearly affected by the lack of a counting system in the language. Performance with quantities greater than three was remarkably poor, but showed a constant coefficient of variation, which is suggestive of an analog estimation process.
DOI: 10.17910/b7.11
title: Caregivers and infants using a traditional "gahvora" cradling practice in Tajikistan

description: Does restricted movement in infancy impair motor skills? And if so, do effects persist into early childhood? Researchers have long documented the importance of movement for infant motor development, and clinicians have designed exercise regimens and interventions to promote motor development in infants with disabilities. However, for ethical reasons, the effects of restriction on motor development are largely unexamined. Infants in Central Asia spend large portions of the day swaddled and bound in a “gahvora” cradle, presenting a unique opportunity to investigate the effects of restriction on motor development by exploiting natural variations in cultural practices. We investigated short-term effects of cradling in 182 1- to 24-month-old infants in Tajikistan. Infants showed striking delays in motor skills compared to World Health Organization standards: At 12 months of age, when 97% of infants crawl and 50% walk by WHO standards, only 53% of Tajik infants crawled and none walked. Delays showed a dose-response effect: Infants with longer cradle durations and less time awake unrestricted showed less advanced motor skills.
DOI: 10.17910/b7059d
title: Facial expressions in 6-month old infants and their parents in the still face paradigm and attachment at 15 months in the Strange Situation

description: Six-month-old infants and their parents were video-recorded in the Face-to-Face/Still-Face (FFSF) procedure (Adamson & Frick, 2003). Infants sat in a carseat and their parents sat across from them. Parents and infants engaged in 3 minutes of natural positive interaction, then 2 minutes of parent still-face in which parents were asked to not respond to their infants, and then 3 minutes of renewed interaction. At 15 months, these infants and parents then completed the Strange Situation to assess attachment security, which consists of a series of separations and reunions. Consent was obtained to share six of the twelve dyads.
DOI: 10.17910/b7vc7g
title: Excerpt volume: Human quadrupeds, primate quadrupedalism, and Uner Tan Syndrome

description: Since 2005, an extensive literature documents individuals from several families afflicted with “Uner Tan Syndrome (UTS),” a condition that in its most extreme form is characterized by cerebellar hypoplasia, loss of balance and coordination, impaired cognitive abilities, and habitual quadrupedal gait on hands and feet. Some researchers have interpreted habitual use of quadrupedalism by these individuals from an evolutionary perspective, suggesting that it represents an atavistic expression of our quadrupedal primate ancestry or “devolution.” In support of this idea, individuals with “UTS” are said to use diagonal sequence quadrupedalism, a type of quadrupedal gait that distinguishes primates from most other mammals. Although the use of primate-like quadrupedal gait in humans would not be sufficient to support the conclusion of evolutionary “reversal,” no quantitative gait analyses were presented to support this claim. Using standard gait analysis of 518 quadrupedal strides from video sequences of individuals with “UTS”, we found that these humans almost exclusively used lateral sequence–not diagonal sequence–quadrupedal gaits. The quadrupedal gait of these individuals has therefore been erroneously described as primate-like, further weakening the “devolution” hypothesis. In fact, the quadrupedalism exhibited by individuals with UTS resembles that of healthy adult humans asked to walk quadrupedally in an experimental setting. We conclude that quadrupedalism in healthy adults or those with a physical disability can be explained using biomechanical principles rather than evolutionary assumptions.
DOI: 10.17910/b7qp46
title: An analysis of optic flow observed by infants during natural activities

description: Global pattern of optic flow can distinguish between different types of self-motion, such as rotation versus translation and forward/backward translation from up/down or side-to-side translation. The circumstances in which human observers produce different types of eye, head, and body motions differ across the life span, in part due to changes in locomotor abilities and declines in the frequency of passive locomotion. Scene geometry and body posture and position also contribute to the statistics of optic flow. Previous research has shown that 9.5 month-old infants undergoing passive locomotion -- carried by their parents in a forward facing carrier -- view different patterns and speeds of retinal- and head-centered optic flow (Raudies et al., 2012). Here we assess the patterns and speeds of head-centered optic flow experienced by infants across a wider range of ages, postures, and geometries. The data come from videos recorded from infant and adult observers who wore head-mounted cameras while they performed simple natural activities -- walking, sitting, playing with toys, and interacting with caregivers. We estimated optic flow from short (~30 sec) long segments using the method of Brox et al. (2004). From the flow estimates, we characterized the relative frequency of global rotation (yaw, pitch, and roll) and translation (forward/backward, up/down, and side to side) patterns and overall speeds. We found that infants who are not moving passively view translational flow patterns significantly more often than infant/mother dyads in paired locomotion. Further, infants who are not coupled to an adult in locomotion view a broader, wider, and slower distribution of flow speeds. Thus, the statistics of optic flow differ depending on the type (active vs. passive) self-motion. This implies that the relative frequency of experienced flow patterns and speeds may change substantially across development. Computer vision-based techniques permit a detailed analysis of the statistics of the natural visual environment during development.
DOI: 10.17910/b7kw28
title: Excerpt volume: Specificity of learning: Why infants fall over a veritable cliff

description: Nine-month-old infants were tested at the precipice of safe and risky gaps in the surface of support. Their reaching and avoidance responses were compared in two postures, an experienced sitting posture and a less familiar crawling posture. The babies avoided reaching over risky gaps in the sitting posture but fell into risky gaps while attempting to reach in the crawling posture. This dissociation between developmental changes in posture suggests that (a) each postural milestone represents a different, modularly organized control system and (b) infants' adaptive avoidance responses are based on information about their postural stability relative to the gap size. Moreover, the results belie previous accounts suggesting that avoidance of a disparity in depth of the ground surface depends on general knowledge such as fear of heights, associations between depth information and falling, or knowledge that the body cannot be supported in empty space.
DOI: 10.17910/b7g59r
title: Preliminary investigation of visual attention to human figures in photographs: Potential considerations for the design of aided AAC visual scene displays

description: Purpose: Many individuals with complex communication needs may benefit from visual aided augmentative and alternative communication systems. In visual scene displays (VSDs), language concepts are embedded into a photograph of a naturalistic event. Humans play a central role in communication development and might be important elements in VSDs. However, many VSDs omit human figures. In this study, the authors sought to describe the distribution of visual attention to humans in naturalistic scenes as compared with other elements. Method: Nineteen college students observed 8 photographs in which a human figure appeared near 1 or more items that might be expected to compete for visual attention (such as a Christmas tree or a table loaded with food). Eye-tracking technology allowed precise recording of participants' gaze. The fixation duration over a 7-s viewing period and latency to view elements in the photograph were measured. Results: Participants fixated on the human figures more rapidly and for longer than expected based on the size of these figures, regardless of the other elements in the scene. Conclusions: Human figures attract attention in a photograph even when presented alongside other attractive distracters. Results suggest that humans may be a powerful means to attract visual attention to key elements in VSDs.
DOI: 10.17910/b7bc7t
title: Excerpt volume: Learning in the development of infant locomotion

description: Infants master crawling and walking in an environment filled with varied and unfamiliar surfaces. At the same time, infants' bodies and skills continually change. The changing demands of everyday locomotion require infants to adapt locomotion to the properties of the terrain and to their own physical abilities. This Monograph examines how infants acquire adaptive locomotion in a novel task--going up and down slopes. Infants were tested longitudinally from their first week of crawling until several weeks after they began walking. Everyday locomotor experience played a central role in adaptive responding. Over weeks of crawling, infants' judgments became increasingly accurate, and exploration became increasingly efficient. There was no transfer over the transition from crawling to walking. Instead, infants learned, all over again, how to cope with slopes from an upright position. Findings indicate that learning generalized from everyday experience traveling over flat surfaces at home but that learning was specific to infants' typical method of locomotion and vantage point. Moreover, learning was not the result of simple associations between a particular locomotor response and a particular slope. Rather, infants learned to gauge their abilities on-line as they encountered each hill at the start of the trial. Change in locomotor responses and exploratory movements revealed a process of differentiation and selection spurred by changes in infants' everyday experience, body dimensions, and locomotor proficiency on flat ground.
DOI: 10.17910/b76p4j
title: Where infants look determines how they see: eye movements and object perception performance in 3-month-olds

description: A fundamental question of perceptual development concerns how infants come to perceive partly hidden objects as unified across a spatial gap imposed by an occluder. Much is known about the time course of development of perceptual completion during the first several months after birth, as well as some of the visual information that supports unity perception in infants. The goal of this investigation was to examine the inputs to this process. We recorded eye movements in 3-month-old infants as they participated in a standard object unity task and found systematic differences in scanning patterns between those infants whose post-habituation preferences were indicative of unity perception versus those infants who did not perceive unity. Perceivers, relative to nonperceivers, scanned more reliably in the vicinity of the visible rod parts and scanned more frequently across the range of rod motion. These results suggest that emerging object concepts are tied closely to available visual information in the environment, and the process of information pickup.
DOI: 10.17910/b7z593
title: Four-month-olds' discrimination of optic flow patterns depicting different directions of observer motion

description: One of the most powerful sources of information about spatial relationships available to mobile organisms is the pattern of visual motion called optic flow. Despite its importance for spatial perception and for guiding locomotion, very little is known about how the ability to perceive one’s direction of motion, or heading, from optic flow develops early in life. In this article, we report the results of 3 experiments that tested the abilities of 4-month-old infants to discriminate optic flow patterns simulating different directions of self-motion. The combined results from 2 different experimental paradigms suggest that 4-month-olds discriminate optic flow patterns that simulate only large (&gt;32 deg) changes in the direction of the observer’s motion through space. This suggests that prior to the onset of locomotion, there are limitations on infants’ abilities to process patterns of optic flow related to self-motion.
DOI: 10.17910/b7tg6t
title: Spatio-temporal tuning of coherent motion evoked responses in 4–6 month old infants and adults

description: Motion cues provide a rich source of information about translations of the observer through the environment as well as the movements of objects and surfaces. While the direction of motion can be extracted locally these local measurements are, in general, insufficient for determining object and surface motions. To study the development of local and global motion processing mechanisms, we recorded Visual Evoked Potentials (VEPs) in response to dynamic random dot displays that alternated between coherent rotational motion and random motion at 0.8 Hz. We compared the spatio-temporal tuning of the evoked response in 4–6 months old infants to that of adults by recording over a range of dot displacements and temporal update rates. Responses recorded at the frequency of the coherent motion modulation were tuned for displacement at the occipital midline in both adults in infants. Responses at lateral electrodes were tuned for speed in adults, but not in infants. Infant responses were maximal at a larger range of spatial displacement than that of adults. In contrast, responses recorded at the dot-update rate showed a more similar parametric displacement tuning and scalp topography in infants and adults. Taken together, our results suggest that while local motion processing is relatively mature at 4–6 months, global integration mechanisms exhibit significant immaturities at this age.
DOI: 10.17910/b7pp4w
title: Representing exact number visually using mental abacus

description: Mental abacus (MA) is a system for performing rapid and precise arithmetic by manipulating a mental representation of an abacus, a physical calculation device. Previous work has speculated that MA is based on visual imagery, suggesting that it might be a method of representing exact number nonlinguistically, but given the limitations on visual working memory, it is unknown how MA structures could be stored. We investigated the structure of the representations underlying MA in a group of children in India. Our results suggest that MA is represented in visual working memory by splitting the abacus into a series of columns, each of which is independently stored as a unit with its own detailed substructure. In addition, we show that the computations of practiced MA users (but not those of control participants) are relatively insensitive to verbal interference, consistent with the hypothesis that MA is a nonlinguistic format for exact numerical computation.
DOI: 10.17910/b7k01x
title: Development of infants’ attention to faces during the first year

description: In simple tests of preference, infants as young as newborns prefer faces and face-like stimuli over distractors. Little is known, however, about the development of attention to faces in complex scenes. We recorded eye-movements of 3-, 6-, and 9-month-old infants and adults during free-viewing of clips from A Charlie Brown Christmas (an animated film). The tendency to look at faces increased with age. Using novel computational tools, we found that 3-month-olds were less consistent (across individuals) in where they looked than were older infants. Moreover, younger infants’ fixations were best predicted by low-level image salience, rather than the locations of faces. Between 3 and 9 months of age, infants gradually focused their attention on faces. We discuss several possible interpretations of this shift in terms of social development, cross-modal integration, and attentional/executive control.
DOI: 10.17910/b7f59f
title: Number as a cognitive technology: Evidence from Pirahã language and cognition

description: Does speaking a language without number words change the way speakers of that language perceive exact quantities? The Pirahã are an Amazonian tribe who have been previously studied for their limited numerical system [Gordon, P. (2004). Numerical cognition without words: Evidence from Amazonia. Science 306, 496–499]. We show that the Pirahã have no linguistic method whatsoever for expressing exact quantity, not even “one.” Despite this lack, when retested on the matching tasks used by Gordon, Pirahã speakers were able to perform exact matches with large numbers of objects perfectly but, as previously reported, they were inaccurate on matching tasks involving memory. These results suggest that language for exact number is a cultural invention rather than a linguistic universal, and that number words do not change our underlying representations of number but instead are a cognitive technology for keeping track of the cardinality of large sets across time, space, and changes in modality.
DOI: 10.17910/b79g65
title: Measuring the development of social attention using free-viewing

description: How do young children direct their attention to other people in the natural world? Although many studies have examined the perception of faces and of goal-directed actions, relatively little work has focused on what children will look at in complex and unconstrained viewing environments. To address this question, we showed videos of objects, faces, children playing with toys, and complex social scenes to a large sample of infants and toddlers between 3 and 30 months old. We found systematic developmental changes in what children looked at. When viewing faces alone, younger children looked more at eyes and older children more at mouths, especially when the faces were making expressions or talking. In the more complex videos, older children looked more at hands than younger children, especially when the hands were performing actions. Our results suggest that as children develop they become better able to direct their attention to the parts of complex scenes that are most interesting socially.
DOI: 10.17910/b75p47
title: Visual search and attention to faces during early infancy

description: Newborn babies look preferentially at faces and face-like displays, yet over the course of their first year much changes about both the way infants process visual stimuli and how they allocate their attention to the social world. Despite this initial preference for faces in restricted contexts, the amount that infants look at faces increases considerably during the first year. Is this development related to changes in attentional orienting abilities? We explored this possibility by showing 3-, 6-, and 9-month-olds engaging animated and live-action videos of social stimuli and also measuring their visual search performance with both moving and static search displays. Replicating previous findings, looking at faces increased with age; in addition, the amount of looking at faces was strongly related to the youngest infants’ performance in visual search. These results suggest that infants’ attentional abilities may be an important factor in facilitating their social attention early in development.
DOI: 10.17910/b72018
title: The development of predictive processes in children’s discourse understanding

description: We investigate children's online predictive processing as it occurs naturally, in conversation. We showed 1-7 year-olds short videos of improvised conversation between puppets, controlling for available linguistic information through phonetic manipulation. Even one- and two-year-old children made accurate and spontaneous predictions about when a turn-switch would occur: they gazed at the upcoming speaker before they heard a response begin. This predictive skill relies on both lexical and prosodic information together, and is not tied to either type of information alone. We suggest that children integrate prosodic, lexical, and visual information to effectively predict upcoming linguistic material in conversation.
DOI: 10.17910/b7x59s
title: Magnet imitation task demonstration

description: This is an excerpt of children doing the magnet imitation task on both a touchscreen and on a magnet board. The task allows researchers to probe how children learn to transfer information between 2D and 3D surfaces to examine memory representations. In practice the task has implications for puzzle play and also for learning from touchscreens and television during early childhood. Video file of information about the task. http://www.georgetown.edu/video/1242739572192.html
DOI: 10.17910/b7sg6h
title: Head camera clips: parent infant object play at 36 to 57 weeks of age

description: These 40 video clips were recorded from head cameras worn by 10 infants 36 to 57 weeks of age. There are four video clips per dyad. In two clips the parent was holding an object and showing it to the infant. In two clips the child was manually in contact with an object and interacting it. These clips are from a larger project and were used in an undergraduate class to show objects from the infant’s perspective and how infant handling of an object results in different views than parent handling.