Understanding the development of motion processing by characterizing optic flow experienced by infants and their mothers
Contributors: Gilmore, Rick O., Raudies, Florian, Franchak, John, Adolph, Karen, National Science Foundation (NSF), National Institute of Child Health and Human Development (NICHD)
... Abstract Understanding the development of mature motion processing may require knowledge about the statistics of the visual input that infants are exposed to, how these change across development, and how they influence the maturation of motion-sensitive brain networks. Here we develop a set of techniques to study the optic flow experienced by infants and mothers during locomotion as a first step toward a broader analysis of the statistics of the natural visual environment during development.
Contributors: Fausey, Caitlin M., Jayaraman, Swapnaa, Smith, Linda B.
... Abstract Human development takes place in a social context. Two pervasive sources of social information are faces and hands. Here, we provide the first report of the visual frequency of faces and hands in the everyday scenes available to infants. These scenes were collected by having infants wear head cameras during unconstrained everyday activities. Our corpus of 143 hours of infant-perspective scenes, collected from 34 infants aged 1 month to 2 years, was sampled for analysis at 1/5 Hz. The major finding from this corpus is that the faces and hands of social partners are not equally available throughout the first two years of life. Instead, there is an earlier period of dense face input and a later period of dense hand input. At all ages, hands in these scenes were primarily in contact with objects and the spatio-temporal co-occurrence of hands and faces was greater than expected by chance. The orderliness of the shift from faces to hands suggests a principled transition in the contents of visual experiences and is discussed in terms of the role of developmental gates on the timing and statistics of visual experiences.
Contributors: Adolph, Karen, National Institute of Child Health and Human Development (NICHD)
... Abstract Some grips on the handle of a tool can be planned on the basis of information directly available in the scene. Other grips, however, must be planned on the basis of the final position of the hand. “End-state comfort” grips require an awkward or uncomfortable initial grip so as to later implement the action comfortably and efficiently. From a cognitive perspective, planning for end-state comfort requires a consistent representation of the entire action sequence, including the latter part, which is not based on information directly available in the scene. Many investigators have found that young children fail to demonstrate planning for end-state comfort and that adultlike performance does not appear until about 12 years of age. In 2 experiments, we used a hammering task that engaged children in a goal-directed action with multiple steps. We assessed end-state-comfort planning in novel ways by measuring children’s hand choice, grip choice, and tool implementation over multiple trials. The hammering task also uniquely allowed us to assess the efficiency of implementation. We replicated the previous developmental trend in 4-, 8-, and 12-year-old children with our novel task. Most important, our data revealed that 4-year-olds are in a transitional stage during which several competing strategies were exhibited during a single session. Preschoolers changed their grip within trials and across trials, indicating awareness of errors and a willingness to sacrifice speed for more efficient implementation. The end-state-comfort grip initially competes as one grip type among many but gradually displaces all others. Children’s sensitivity to costs and drive for efficiency may motivate this change.
Contributors: Gilmore, Rick O., National Science Foundation (NSF)
... Abstract 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.
Contributors: Naigles, Letitia
... Abstract Verb learning is clearly a function of observation of real-world contingencies; however, it is argued that such observational information is insufficient to account fully for vocabulary acquisition. This paper provides an experimental validation of Landau & Gleitman's (1985) syntactic bootstrapping procedure; namely, that children may use syntactic information to learn new verbs. Pairs of actions were presented simultaneously with a nonsense verb in one of two syntactic structures. The actions were subsequently separated, and the children (MA = 2;1) were asked to select which action was the referent for the verb. The children's choice of referent was found to be a function of the syntactic structure in which the verb had appeared.
An eye tracking investigation of developmental change in bottom-up attention orienting to faces in cluttered natural scenes
Contributors: Amso, Dima, James S. McDonnell Foundation (JSMF), National Institute of General Medical Sciences (NIGMS)
Contributors: Gilmore, Rick O., Norcia, Anthony M., National Science Foundation (NSF)
... Abstract There exists an abundance of visual symmetry within our environment. Yet research on human perception has almost exclusively been limited to studies of a single type of symmetry— two-fold reflection—leaving uncertainty about human perceptual sensitivity to the other types of symmetry as derived from the mathematics of Group Theory. Clarke et al. (2011) found that five of the seventeen wallpaper groups—P1, P3M1, P31M, P6, and P6M—have a high degree of self-similarity, as determined by the frequency with which participants grouped random-dot noise representations of the same wallpaper group together. The current study attempts to replicate Clarke et al. (2011) in a limited form. Here, we sought to understand the salience of lower-order features within each of five wallpaper groups, and concordantly, their impact on symmetry detection. Adult participants were presented with twenty exemplars of each of the five aforementioned wallpaper groups and instructed to sort them into as many subsets as they wished based on any criteria they saw appropriate. Participants were then surveyed on the methods they used to classify these images. Analysis suggest several factors—including contrast and presence of salient secondary structures—influence the detection of symmetry in wallpaper groups.
Facial expressions in 6-month old infants and their parents in the still face paradigm and attachment at 15 months in the Strange Situation
Contributors: Messinger, Daniel, National Science Foundation (NSF), National Institutes of Health (NIH), Autism Speaks
... Abstract 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.
Contributors: Frank, Michael C.
... Abstract 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.
Contributors: Rhodes, Marjorie, National Science Foundation (NSF)
... Abstract Social essentialism entails the belief that certain social categories (e.g., gender, race) mark fundamentally distinct kinds of people. Essentialist beliefs have pernicious consequences, supporting social stereotyping and contributing to prejudice. How does social essentialism develop? In the studies reported here, we tested the hypothesis that generic language facilitates the cultural transmission of social essentialism. Two studies found that hearing generic language about a novel social category diverse for race, ethnicity, age, and sex led 4-y-olds and adults to develop essentialist beliefs about that social category. A third study documented that experimentally inducing parents to hold essentialist beliefs about a novel social category led them to produce more generic language when discussing the category with their children. Thus, generic language facilitates the transmission of essentialist beliefs about social categories from parents to children.