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Biomedical subjects

Stephanie M Carlson

Publications and source records attributed to Stephanie M Carlson.

10 recordsLinked to original sources
PubMed2006

The development of executive functioning and theory of mind. A comparison of Chinese and U.S. preschoolers.

Preschoolers' theory-of-mind development follows a similar age trajectory across many cultures. To determine whether these similarities are related to similar underlying ontogenetic processes, we examined whether the relation between theory of mind and executive function commonly found among U.S. preschoolers is also present among Chinese preschoolers. Preschoolers from Beijing, China (N= 109), were administered theory-of-mind and executive-functioning tasks, and their performance was compared with that of a previously studied sample of U.S. preschoolers (N= 107). The Chinese preschoolers outperformed their U.S. counterparts on all measures of executive functioning, but were not similarly advanced in theory-of-mind reasoning. Nonetheless, individual differences in executive functioning predicted theory of mind for children in both cultures. Thus, the relation between executive functioning and theory of mind is robust across two disparate cultures. These findings shed light on why executive functioning is important for theory-of-mind development.

Age Factors↗
PubMed2005

Induction of photosensitivity by heterologous expression of melanopsin.

Melanopsin has been proposed to be the photopigment of the intrinsically photosensitive retinal ganglion cells (ipRGCs); these photoreceptors of the mammalian eye drive circadian and pupillary adjustments through direct projections to the brain. Their action spectrum (lambda(max) approximately 480 nm) implicates an opsin and melanopsin is the only opsin known to exist in these cells. Melanopsin is required for ipRGC photosensitivity and for behavioural photoresponses that survive disrupted rod and cone function. Heterologously expressed melanopsin apparently binds retinaldehyde and mediates photic activation of G proteins. However, its amino-acid sequence differs from vertebrate photosensory opsins and some have suggested that melanopsin may be a photoisomerase, providing retinoid chromophore to an unidentified opsin. To determine whether melanopsin is a functional sensory photopigment, here we transiently expressed it in HEK293 cells that stably expressed TRPC3 channels. Light triggered a membrane depolarization in these cells and increased intracellular calcium. The light response resembled that of ipRGCs, with almost identical spectral sensitivity (lambda(max) approximately 479 nm). The phototransduction pathway included Gq or a related G protein, phospholipase C and TRPC3 channels. We conclude that mammalian melanopsin is a functional sensory photopigment, that it is the photopigment of ganglion-cell photoreceptors, and that these photoreceptors may use an invertebrate-like phototransduction cascade.

Animals↗
PubMed2005

Less is more: executive function and symbolic representation in preschool children.

Executive function is recognized as a critical component of children's cognitive and social development. In two studies, a measure of executive function that had been used in research with chimpanzees was adapted for preschoolers. On this task, called Less Is More, children must point to a smaller reward (two candies) to receive a larger reward (five candies). In Study 1 (N= 101), performance was significantly related to age (3 vs. 4), verbal ability, and established measures of executive function. In Study 2 (N= 128), symbolic representations substituted for real candies in this task. Three-year-olds' performance improved significantly as a function of symbolic distancing. This research has implications for the role of symbol systems in the development of executive control over thought and action.

Age Factors↗
PubMed2005

Developmentally sensitive measures of executive function in preschool children.

Changes in executive functioning in the preschool years are recognized as playing a critical role in cognitive and social development, yet comprehensive data and recommendations about measurement of these changes are lacking. The performance of 602 preschool children on several executive function tasks was analyzed and reported as (a) age trends in performance and (b) task difficulty scales at 2, 3, 4, and 5 to 6 years of age. This analysis informs theories of executive function development and offers researchers an evidence-based guide to task selection and design.

Child↗
PubMed2005

Preschool children's performance in task switching on the dimensional change card sort task: separating the dimensions aids the ability to switch.

Fifty-seven children (53% female) at 3 ages (2 1/2, 3, and 3 1/2 years) were tested on the standard Dimensional Change Card Sort (DCCS) task with integrated stimuli (e.g., a red truck) and on a separated-dimensions version where colorless shapes were presented on a colored background (e.g., a black truck on a red background). Roughly twice as many children successfully switched sorting dimensions when color was a property of the background than when color was a property of the shape itself. Children succeeded 6 months earlier in switching sorting criteria when the dimensions were separated. When evidence of both indecision and accuracy was taken into account, a clear and rich developmental progression emerged. These results support an inhibitory control interpretation of preschoolers' problems on the DCCS task. Diamond theorized that young children can have difficulty integrating features not part of a single object and separating features of a single object so that the object can be categorized first by one attribute and then by another. Preschoolers remain stuck in thinking about objects according to the objects' initially relevant attribute (attentional inertia; Kirkham, Cruess, & Diamond, 2003). To switch perspectives, the old way of thinking about the objects must be inhibited. Separating color and shape reduced the need for such inhibition; a truck was always a truck, and the background was always red.

Child, Preschool↗
PubMed2004

Individual differences in executive functioning and theory of mind: An investigation of inhibitory control and planning ability.

This research examined the relative contributions of two aspects of executive function-inhibitory control and planning ability-to theory of mind in 49 3- and 4-year-olds. Children were given two standard theory of mind measures (Appearance-Reality and False Belief), three inhibitory control tasks (Bear/Dragon, Whisper, and Gift Delay), three planning tasks (Tower of Hanoi, Truck Loading, and Kitten Delivery), and a receptive vocabulary test (Peabody Picture Vocabulary Test [PPVT-3]). Multiple regression analyses indicated that two inhibition tasks (Bear/Dragon and Whisper) were significantly related to theory of mind after accounting for age, receptive vocabulary, and planning. In contrast, the planning tasks did not share unique variance with theory of mind. These results increase our understanding of the specific nature of executive function-theory of mind relations during early childhood.

Child Development↗
PubMed2004

Executive function and theory of mind: stability and prediction from ages 2 to 3.

Several studies have demonstrated a relation between executive functioning (EF) and theory of mind (ToM) in preschoolers, yet the developmental course of this relation remains unknown. Longitudinal stability and EF-ToM relations were examined in 81 children at 24 and 39 months. At Time 1, EF was unrelated to behavioral measures of ToM but was significantly related to parent report of children's internal-state language, independent of vocabulary size. At Time 2, behavioral batteries of EF and ToM were significantly related (r=.50, p<.01). Furthermore, EF (Time 1) significantly predicted ToM (Time 2), independent of several controls. A reciprocal relation (internal-state language --> EF at Time 2) was nonsignificant with the controls included. Individual differences in EF were relatively stable.

Child Development↗
PubMed2004

The characteristics and correlates of fantasy in school-age children: imaginary companions, impersonation, and social understanding.

Past research with 152 preschoolers found that having an imaginary companion or impersonating an imaginary character was positively correlated with theory of mind performance. Three years later, 100 children from this study were retested to assess the developmental course of play with imaginary companions and impersonation of imaginary characters and how these types of role play were related to emotion understanding, self-perception, and personality. The results showed that school-age children interact with imaginary companions and impersonate imaginary characters as much as preschoolers. Overall, 65% of children up to the age of 7 had imaginary companions at some point during their lives. School-age children who did not impersonate scored lower on emotion understanding. Theory of mind at age 4 predicted emotion understanding 3 years later.

Child↗
PubMedDate not supplied

Gesture as a window on children's beginning understanding of false belief.

Given that gestures may provide access to transitions in cognitive development, preschoolers' performance on standard tasks was compared with their performance on a new gesture false belief task. Experiment 1 confirmed that children (N=45, M age=54 months) responded consistently on two gesture tasks and that there is dramatic improvement on both the gesture false belief task and a standard task from ages 3 to 5. In 2 subsequent experiments focusing on children in transition with respect to understanding false beliefs (Ns=34 and 70, M age=48 months), there was a significant advantage of gesture over standard and novel verbal-response tasks. Iconic gesture may facilitate reasoning about opaque mental states in children who are rapidly developing concepts of mind.

Child, Preschool↗