Comparing Me to You: Comparison Between Novel and Familiar Goal-Directed Actions Facilitates Goal Extraction and Imitation

Recognizing the goals of others' actions is critical for much of human development and social life. Origins of this knowledge exist in the first year and are a function of both acting as an intentional agent and observing movement cues in actions. In this dissertation, I explore a new mechanism I believe plays an important role in infants' understanding of novel actions---comparison. In four studies, I examine how the opportunity to compare a familiar action with a novel, tool use action (through physical alignment of the two actions) helps 7- and 10-month-old infants extract and imitate the goal of a tool use action. In Studies 1 and 2, 7-month-old infants given the chance to compare their own reach for a toy with an experimenter's reach using a claw later imitated the goals of an experimenter's tool use actions. In contrast, infants who engaged with the claw, were familiarized with the claw's causal properties, learned the associations between claw and toys, or interacted in a socially contingent manner with the experimenter using the claw did not later imitate the experimenter's goals. Study 3 replicated the finding that engagement in physical alignment facilitated goal extraction and imitation and indicated that this was true for older infants (10-month-olds). It also demonstrated that observation of the same physical alignment did not lead to goal imitation at this age. Finally, Study 4 revealed that 10-month-old infants could learn about the goals of novel actions through the observation of physical alignment when a cue to focus on the goal of the two actions was presented during the alignment process (i.e., a verbal label), indicating that infants gained a conceptual representation of the goal and used structure mapping to extract the common goal between actions. Infants who heard a non-label vocalization during the observation of physical alignment did not later imitate the experimenter's goals. The nature, breadth, and implications of these findings are discussed. Together, these findings indicate that infants can extract the goal-relation of a novel action through comparison processes; comparison could thus have a broad impact on the development of action knowledge

What's in a Mitten?: The Effects of Active Versus Passive Experience on Action Understanding

Prior research has shown that young infants understand something about others' goals. This understanding has been developmentally linked to infants' own actions. An open question is what aspects of experience are crucial to action understanding. In the current studies, we sought to examine the relation between experience and action understanding in 3-month-old infants and to investigate the differential effects of active and passive experience. Findings from Study 1 demonstrated a threshold effect: a minimal amount of active experience led to subsequent action understanding. In Study 2, we assessed whether visual experience alone would have the same effect by giving another group of infants matched passive experience. These infants, however, did not reap the same benefits from passive experience. These findings demonstrate that active experience provides important information, above and beyond that which can be gleaned from passive experience, at a time when intention understanding is first emerging

Exploring the benefits of doll play through neuroscience

It has long been hypothesized that pretend play is beneficial to social and cognitive development. However, there is little evidence regarding the neural regions that are active while children engage in pretend play. We examined the activation of prefrontal and posterior superior temporal sulcus (pSTS) regions using near-infrared spectroscopy while 42 4- to 8-year-old children freely played with dolls or tablet games with a social partner or by themselves. Social play activated right prefrontal regions more than solo play. Children engaged the pSTS during solo doll play but not during solo tablet play, suggesting they were rehearsing social cognitive skills more with dolls. These findings suggest social play utilizes multiple neural regions and highlight how doll play can achieve similar patterns of activation, even when children play by themselves. Doll play may provide a unique opportunity for children to practice social interactions important for developing social-emotional skills, such as empathy

Young children’s memories for social actions: influences of age, theory of mind, and motor complexity

Children learn actions performed by a social partner better when they misremember these actions as their own. Identifying the factors that alter the propensity to make appropriation errors is critical for optimizing social learning. In two experiments (N = 110), we investigate the developmental trajectory of appropriation errors and examine social‐cognitive and motor‐related factors in 3‐ to 8‐year‐olds. Children with better theory of mind (ToM) skills made fewer appropriation errors for motorically complex actions. Appropriation errors did not differ as a function of ToM if children could perform the corresponding actions. A second experiment replicated this effect and found no influence of collaborative context on appropriation errors. This research sheds light on the complex relations among development, social‐cognition, and motor‐related factors

Doll play prompts social thinking and social talking: representations of internal state language in the brain

Doll play provides opportunities for children to practice social skills by creating imaginary worlds, taking others’ perspectives, and talking about others’ internal states. Previous research using functional near-infrared spectroscopy (fNIRS) found a region over the posterior superior temporal sulcus (pSTS) was more active during solo doll play than solo tablet play, implying that doll play might present opportunities for rehearsing theory of mind and empathy skills, even when playing alone. In this research, we addressed this more directly by investigating 4–8-year-old children's (N = 33) use of internal state language (ISL; i.e., references to emotions, desires, and cognitions) when playing with dolls and on tablets, both by themselves and with a social partner, and their associated brain activity in the pSTS using fNIRS. We found that children used more ISL about others when playing with dolls than when playing on tablets, particularly when they were playing alone. This mirrored the patterns seen in pSTS activity in previous research. When individual variability in ISL about others was considered, more ISL about others was linked to stronger pSTS activation. Thus, variability in pSTS activity during play is not about the perceptual or physical differences between toys (e.g., dolls are more human-like) but about what children think about when they engage in different kinds of play. This is the first research to investigate brain activity during spontaneously occurring ISL and indicates that children have a tendency to take and discuss others’ perspectives during doll play, with implications for social processing in the brain. A video abstract of this article can be viewed at https://youtu.be/58HgxbuhBzU

Sensitivity to structure in action sequences:an infant event-related potential study

Infants are sensitive to structure and patterns within continuous streams of sensory input. This sensitivity relies on statistical learning, the ability to detect predictable regularities in spatial and temporal sequences. Recent evidence has shown that infants can detect statistical regularities in action sequences they observe, but little is known about the neural process that give rise to this ability. In the current experiment, we combined electroencephalography (EEG) with eye-tracking to identify electrophysiological markers that indicate whether 8–11-month-old infants detect violations to learned regularities in action sequences, and to relate these markers to behavioral measures of anticipation during learning. In a learning phase, infants observed an actor performing a sequence featuring two deterministic pairs embedded within an otherwise random sequence. Thus, the first action of each pair was predictive of what would occur next. One of the pairs caused an action-effect, whereas the second did not. In a subsequent test phase, infants observed another sequence that included deviant pairs, violating the previously observed action pairs. Event-related potential (ERP) responses were analyzed and compared between the deviant and the original action pairs. Findings reveal that infants demonstrated a greater Negative central (Nc) ERP response to the deviant actions for the pair that caused the action-effect, which was consistent with their visual anticipations during the learning phase. Findings are discussed in terms of the neural and behavioral processes underlying perception and learning of structured action sequences

linc-mipep and linc-wrb encode micropeptides that regulate chromatin accessibility in vertebrate-specific neural cells

Thousands of long intergenic non-coding RNAs (lincRNAs) are transcribed throughout the vertebrate genome. A subset of lincRNAs enriched in developing brains have recently been found to contain cryptic open-reading frames and are speculated to encode micropeptides. However, systematic identification and functional assessment of these transcripts have been hindered by technical challenges caused by their small size. Here, we show that two putative lincRNAs (linc-mipep, also called lnc-rps25, and linc-wrb) encode micropeptides with homology to the vertebrate-specific chromatin architectural protein, Hmgn1, and demonstrate that they are required for development of vertebrate-specific brain cell types. Specifically, we show that NMDA receptor-mediated pathways are dysregulated in zebrafish lacking these micropeptides and that their loss preferentially alters the gene regulatory networks that establish cerebellar cells and oligodendrocytes - evolutionarily newer cell types that develop postnatally in humans. These findings reveal a key missing link in the evolution of vertebrate brain cell development and illustrate a genetic basis for how some neural cell types are more susceptible to chromatin disruptions, with implications for neurodevelopmental disorders and disease

Navigating to new frontiers in behavioral neuroscience: traditional neuropsychological tests predict human performance on a rodent-inspired radial-arm maze

We constructed an 11-arm, walk-through, human radial-arm maze (HRAM) as a translational instrument to compare existing methodology in the areas of rodent and human learning and memory research. The HRAM, utilized here, serves as an intermediary test between the classic rat radial-arm maze (RAM) and standard human neuropsychological and cognitive tests. We show that the HRAM is a useful instrument to examine working memory ability, explore the relationships between rodent and human memory and cognition models, and evaluate factors that contribute to human navigational ability. One-hundred-and-fifty-seven participants were tested on the HRAM, and scores were compared to performance on a standard cognitive battery focused on episodic memory, working memory capacity, and visuospatial ability. We found that errors on the HRAM increased as working memory demand became elevated, similar to the pattern typically seen in rodents, and that for this task, performance appears similar to Miller's classic description of a processing-inclusive human working memory capacity of 7 ± 2 items. Regression analysis revealed that measures of working memory capacity and visuospatial ability accounted for a large proportion of variance in HRAM scores, while measures of episodic memory and general intelligence did not serve as significant predictors of HRAM performance. We present the HRAM as a novel instrument for measuring navigational behavior in humans, as is traditionally done in basic science studies evaluating rodent learning and memory, thus providing a useful tool to help connect and translate between human and rodent models of cognitive functioning