Simona Ghetti, Ph.D. - US grants

False-Memory rejection in Children and Adults: The Role of the Memorability-based Strategy

Have you ever witnessed any episode of interpersonal violence? Assuming that you did not, how did you determine that the correct answer to that question is indeed No? You may, perhaps, have decided that you never had that experience, after you conducted a memory search and failed to retrieve any relevant information. It is commonplace, however, to fail to retrieve information from memory, not because of lack of experience, but because of forgetting. Thus, the simple absence of a "positive memory" (i.e., memory of an occurrence) may not provide a sufficient basis for rejection of an event occurrence. An intuitively appealing account is that individuals use the perceived memorability of an event, in conjunction with failure to retrieve any information about that event, to infer the event's nonoccurrence: If you expect to remember witnessing interpersonal violence, yet you cannot retrieve any memory for this event, then you may infer that you have had this experience.
In previously NSF-funded research, evidence for the existence of this psychological mechanism was found. This mechanism has been labeled memorability-based strategy (MBS). In the first wave of studies, we began to examine age differences in the ability to rely on the MBS in childhood, and the conditions that promote and challenge the use of the MBS. This research showed that spontaneous use of the MBS is not detected before age 9, and that specific instructions about the MBS only partially helped children younger than 9. Further, results showed that even older children's and adults' use of the MBS may be compromised after individuals deliberately imagine events or knowingly confabulate about false details concerning such events.
The current studies build directly on these previous studies to identify favorable conditions under which MBS-training results in enhancement of false-memory rejection. Specifically, the current research is aimed at enhancing the MBS-training effectiveness to induce reliance on the MBS in children who would not spontaneously use it (i.e., 7-year-olds), and strengthen its use in children who can spontaneously implement it (i.e., children aged 9 or older). In addition, we will investigate the role of individual differences (e.g., inference skills, executive function, and self-efficacy) in the ability to use the MBS ability and in that of taking advantage of the training. Two experiments will be conducted to achieve these aims.
This research will have important implications for both theory and application. New theoretical knowledge about the conditions under which children and adults use the MBS to avoid false-memory formation will be gained. Although factors influencing false-memory acceptance (and its development) have been studied extensively, the factors responsible for false-memory rejection have received relatively little attention. Yet, such factors may be crucial for individuals' abilities to communicate effectively that events did not happen and provide accurate statements. For theory, an understanding of false-memory rejection is necessary for a comprehensive theory of memory accuracy.
For application, findings from the current research will facilitate the development of age-specific forensic procedures that enhance witnesses' abilities to identify false information and gate it out of their reports. The vast literature on child memory and suggestibility has led to the development of useful procedures to enhance children's recollections in forensic settings, but these procedures may not be as successful at helping children identify and reject false events. Presently, no parallel age-specific procedures have been introduced to promote false-memory rejection, which is equally important for the validity of child testimony.

[unreadable] DESCRIPTION (provided by applicant): Background and Aims: The ability to recognize past events is a fundamental aspect of our ability to remember. Two processes are thought to underlie recognition memory: recollection and familiarity. Recollection is the process that allows for the retrieval of distinct features associated with the context in which the event was originally encountered. Familiarity is the process that allows for the global assessment of the strength of the memory trace of the event, in the absence of memory for contextual features. A developmental dissociation between the two processes has been documented in behavioral research: Whereas recollection appears to continue to develop over the course of childhood and adolescence, familiarity appears to become relatively stable during childhood. Cognitive neuroscience research with adults has shown that recollection and familiarity rely on distinct brain structures and that activity in these brain regions is dissociable both at time of encoding and at time of retrieval. One gap in our knowledge concerns the neural mechanisms underlying the developmental dissociation between recollection and familiarity. The proposed research aims to address this gap by examining encoding-related processes during development. The specific aims of the proposed project are: (1) to identify the neural correlates of the development of recollection, and (2) to identify the neural correlates of the development of familiarity. Methods: The proposed research involves an event-related functional magnetic resonance imaging (fMRI) experiment with 8-, 10-, 14-, and 18-years-olds (20 participants per age group). Participants will be scanned during an incidental encoding task. Memory for the items processed in the scanner will be tested later, and measures of brain activity will be extracted as a function of this later memory performance. Significance: The proposed research will generate new knowledge about age-differences in the neural substrates of recollection and familiarity related to encoding processes. The findings will contribute to the development of a more comprehensive theory of recognition memory, as well as to an understanding of the relation between brain functioning and cognitive development. Relevance for public health: Knowledge about typical memory development is critical to understanding atypical memory development, as seen, for example, in child populations with traumatic brain injury or type-1 diabetes. Understanding the neural correlates of the development of various learning mechanisms is relevant to facilitating adaptive functioning in a wide range of domains. [unreadable] [unreadable] [unreadable]

When performing a cognitive task or answering a question, can young children tell when they might be wrong? Can they use their subjective assessment of uncertainty to guide decisions about future behaviors? How do children gain the ability to introspect on the experience of uncertainty? Answers to these questions will provide critical insight into basic mechanisms of cognitive development during the preschool years. To date, a large body of research has focused on young children's conceptual understanding of knowledge (e.g., children's understanding that knowing differs from guessing); however, the study of uncertainty monitoring (i.e., the ability to perform on-line assessments of one's own subjective experience of un/certainty in the accuracy of a response) has been largely neglected. Yet the ability to monitor uncertainty has significant implications. Children may learn more effectively if they recognize when they are uncertain about their knowledge and, as a result, they act to overcome this state of uncertainty (e.g., by asking for clarification, requesting more information, studying materials more carefully). The proposed research will examine the emergence and early development of uncertainty monitoring with three experiments. Experiment 1 will investigate whether preschoolers can introspect on their uncertainty. To do so, 3-, 4- and 5-year-olds will be trained to provide confidence judgments on a number of cognitive tasks. It is expected that even 3-year-olds will show some uncertainty monitoring ability, as indicated by higher confidence ratings for accurate compared to inaccurate responses in the task, but improvements in this ability will be observed throughout the preschool years. Experiment 2 will examine 3-, 4- and 5-year-olds' ability to use their uncertainty to guide their decisions. Experiment 2a will examine whether children are more likely to ask for clarification when they are uncertain, compared to when they are certain, whereas Experiment 2b will examine whether children are more likely to refrain from responding when they are uncertain compared to when they are certain. It is expected that even 3-year-olds will show evidence of reliance on uncertainty in both contexts, but that, with age, children become increasingly attuned and able to act on their uncertainty states.

The ability to evaluate one's sense of certainty about the likely accuracy of one's knowledge and the ability to act strategically in the face of this evaluation are essential to learning. Although there is a general consensus that children learn rapidly from an early age, a dominant view is that young children cannot advance their learning by reflecting on their own uncertainty states. The proposed research will provide new insight into early learning and establish whether, even at young ages, children gain from reflecting on their states of uncertainty. In addition to providing critical insight into mechanisms of learning and development, the results of the current research will have important implications for educational settings and other contexts where children's awareness of the degree to which they know or do not know something is critical (e.g., legal settings). Findings from the proposed research may promote the development of age-specific procedures that enhance young children's ability to report on their current states of knowledge.

DESCRIPTION (provided by applicant): Episodic memory, or the ability to consciously remember past events, is central to the human experience. In a number of mental health disorders, this form of memory is among the most severely impaired cognitive functions. In the case of schizophrenia, episodic memory dysfunction precedes the onset of the full-blown disorder and predicts long-term functional outcomes. In typically developing children, episodic memory improves rapidly during childhood, and then improves more slowly during adolescence. The brain mechanisms supporting these improvements are not yet understood. Neuroscientific research has shown that the hippocampus plays a fundamental role in episodic memory, supporting the formation and retrieval of representations that bind the different aspects of an event. By contrast, lateral prefrontal cortex is thought to play a supportive role in episodic memory, controlling the strategic encoding and retrieval of relevant memories through long-range projections to the hippocampus. It has long been assumed that the hippocampus-dependent binding mechanism is already in place by early childhood, and that the large changes in episodic memory observed during middle childhood and beyond result from the protracted development of the prefrontal cortex. Challenging this view, the proposed research will investigate whether and how changes in the hippocampus - as well as changes in specific tracts that project to the hippocampus - contribute to the development of episodic memory. The proposed research will examine the within-individual changes in brain structure and brain function that underlie changes in episodic memory performance from age 8 to 14 years. To this end, a sample of 180 typically-developing children will be tested three times over the course of 5 years. As compared with cross- sectional research, which is the norm in developmental cognitive neuroscience, this longitudinal approach will enable the identification of the antecedents and consequences of changes in brain structure, brain function, and episodic memory. Relevance to Public Health: The proposed research will lay the foundation for future research on such mental health disorders as schizophrenia, for which atypical hippocampal development may be an early indicator of disease onset.

Individuals' ability to recognize when they know something, when they do not, and when they are unsure is critical for everyday functioning. To operate effectively in day to day activities, individuals must realize when they need to seek out additional information in order to avoid acting on faulty or insufficient information. An important question is how young children develop the ability to assess their own knowledge and how they learn to recognize and act on their own uncertainty. This project investigates the emergence of this ability in 2- to 3-year-old children.

Previous research indicates that children as young as three years of age recognize when they are likely to be wrong in answering a question. They avoid answering questions to which they do not know the answer, express low confidence in their responses, and request further information. Even toddlers exhibit behaviors that suggest they are tracking their own knowledge states, hesitating when their knowledge is limited and looking confident when they have relevant information. However, it is not clear if these indicators reliably reflect the accuracy of toddlers' knowledge, and whether they contribute to later emerging abilities to introspect on how well they know. In this project, Dr. Simona Ghetti will address this question, investigating the developmental emergence of these abilities. The study investigates the hypothesis that toddlers' behaviors (e.g., hesitation) and their rudimentary awareness of their states of ignorance (e.g., captured by such statements as 'I don't know') are developmental precursors of the ability to overtly introspect on uncertainty. Using a longitudinal design, the investigator will explore how these precursor behaviors at age 2 relate to measures of the ability to introspect on uncertainty at age 3.

This research will provide new insight into the emergence of introspection, which will be beneficial in educational settings. Findings from the proposed research may help identify early cues to uncertainty that could signal to educators the need to provide additional information, and might promote the development of age-specific procedures to enhance young children's ability to monitor their own knowledge states.

Understanding the patterns of communication between brain regions, and how they develop across childhood, is critical for understanding the development of the neural mechanisms that implement complex cognitive operations such as reasoning. Functional connectivity, or correlations in patterns of brain activation (measured via fMRI), is thought to reflect this inter-regional communication. But communication between brain regions ultimately depends on structural connectivity: the white matter tracts that, either directly or indirectly, connect them. This proposal is aimed at resolving two open questions: 1) What are the dynamic relationships between structural and functional connectivity, for the key networks known to be involved in reasoning and other higher cognitive processes, as these develop together across childhood?, and 2) How do these dynamic relationships affect developmental improvements in reasoning ability? The answers that we obtain will provide both fundamental insight into the development of brain connectivity and mechanistic insight into the development of reasoning ability. This knowledge could impact future research both on educational and training programs designed to teach reasoning ability, and on interventions or medical programs designed to correct problems in reasoning.

To address these questions, we will combine fMRI, DTI, and behavioral data from three longitudinal developmental datasets, collected at UC Berkeley, UC Davis, and Vanderbilt University. By combining datasets, we are able to examine longitudinal data from 400 children and young adults between the ages of 6 and 22. Our primary measures of interest include a) intrinsic functional connectivity between specific regions of interest; b) structural connectivity, measured via fractional anisotropy along tracts that connect these regions; and c) reasoning ability, measured via standard cognitive tests. Our main analyses will focus on connectivity within and between two brain networks, the fronto-parietal network and cingulo-opercular network, which are most closely associated with reasoning and other higher cognitive functions. Mixed-model regression analyses will be employed to examine concurrent relationships among structural and functional connectivity in these networks and reasoning ability. Multivariate latent difference score models will be employed to examine lead-lag relationships. The outcome of this research will be a model of interacting structural and functional connectivity development across childhood, and of how the co-development of these two indicators of neural communication relates to developmental improvements in reasoning ability.

PROJECT SUMMARY Episodic memory, or the ability to remember past events with specific detail, is central to the human experience and is related to learning and adaptive functioning in a variety of domains. In typically developing children, episodic memory improves emerges during infancy and improves during early childhood and beyond. Despite remarkable early episodic memory skills, most early recollections are lost to infantile amnesia, individuals' inability to recall events occurred in the first 2 or 3 years of life. Neuroscientific research has shown that the hippocampus plays a fundamental role in episodic memory, supporting the formation and retrieval of representations that bind the different aspects of an event. Of importance, developmental processes within the hippocampus are hypothesized to be primarily responsible for both the early emergence of episodic memory in children and the loss of early recollections due to infantile amnesia. However, these hypotheses are based on non-human models and no direct in-vivo evidence of early hippocampal contribution to early memory functioning and loss is available to date. This limitation is mostly due to the methodological challenge of acquiring neuroimaging data, particularly task-related functional neuroimaging data, from young children. The proposed research will explore new methods to test hippocampal structure and function in toddlers and begin to examine within-individual changes that underlie improvements and loss of episodic memory performance from 25 to 40 months, a period during which episodic memory improves, but infantile amnesia operates. Relevance to Public Health: Healthy episodic memory provides a foundation for the emergence and development of autobiographical memory, continuity of self from past to future, and is associated with the skills assessed in many measures of intellectual ability and achievement. Finally, the development of episodic memory is impaired following even mild forms of acquired neurological insult, mental health conditions such as anxiety and depression, and neurodevelopmental disorders underscoring that a characterization of its development is key to understanding adaptive functioning in various populations of children.

Project Summary. Children with type 1 diabetes (T1D) suffer from subtle cognitive impairments and structural alterations in the brain. These impairments progress with age and may eventually lead to increased difficulty managing the disease, resulting in worsening glycemic control, potentially life-threatening complications, and reductions in quality of life. Causes of cognitive decline in T1D are not well understood. Episodes of hypoglycemia, chronic hyperglycemia, glycemic variability and diabetic ketoacidosis (DKA) have all been suggested to play roles. Increased understanding of factors linked to cognitive decline in T1D, and the mechanisms responsible for these associations, is essential such that interventions to preserve cognition could be proposed. Recent data suggest that neuroinflammation resulting from hyperglycemia and episodes of DKA may be play a prominent role in causing cognitive decline. There is also evidence that modifiable factors such as nutrition, exercise, and sleep quality might modulate effects of chronic neuroinflammation and influence cognitive outcomes. In this project, we will engage in efforts to plan a comprehensive study of factors associated with cognition in children with T1D. At the completion of the proposed planning project, we will be prepared to conduct a longitudinal cohort study of children with newly diagnosed T1D. This study will determine how glycemic control and DKA exposure predict altered brain structure and cognition and establish whether markers of neuronal injury and inflammatory processes explain these longitudinal relations. Proposed assessments will include T1D-related factors (glycemic control, glycemic variability, hypoglycemia, DKA), brain structure and cognitive function (attention, memory and IQ). In addition, we will plan measurements of inflammatory mediators and markers of neuroinflammation using blood assays (cytokine measurements, exosome analyses, RNA microarrays), and evaluate factors that might modify inflammation such as diet (nutrient content), sleep quality and exercise. To optimize the study design, we will utilize the expertise of a multidisciplinary team to develop the study protocol, including experts in pediatric diabetes, cognitive development, neural and systemic inflammation, MR imaging, nutrition, sleep medicine, and data science. The team will work together to finalizing the protocol, work-flow and outcome measures, and identify the necessary computational infrastructure and data analysis strategies. The team will also assess study feasibility (factors affecting enrollment success and tolerance of the protocol) and determine necessary sample size by evaluating variability in biochemical and imaging measures. Alternative approaches to increase participant retention, such as remote (online) versus in person cognitive testing, will be explored. At the conclusion of this planning project, we will have developed and optimized a protocol to explore factors associated with cognitive decline in children with T1D, laying a foundation for future studies aimed at preserving cognitive function.

PROJECT SUMMARY Episodic memory, or the ability to remember past events with specific detail, is central to the human experience and is related to learning and adaptive functioning in a variety of domains. In typically developing children, episodic memory improves emerges during infancy and improves during early childhood and beyond. Despite remarkable early episodic memory skills, most early recollections are lost to infantile amnesia, individuals' inability to recall events occurred in the first 2 or 3 years of life. Developmental processes within the hippocampus are hypothesized to be primarily responsible for both the early emergence of episodic memory in children and the loss of early recollections due to infantile amnesia. However, these hypotheses are based on non-human models and in-vivo investigations in early human development have been significantly limited by the methodological challenge of acquiring neuroimaging data, particularly task-related functional neuroimaging data, from young children. Recent studies in adults have highlighted that the hippocampus is involved in the acquisition of the initially arbitrary association between new words and their referents, a capacity markedly impaired in hippocampal amnesia. We propose to leverage the remarkable word-learning skills in infants and toddlers to explore whether neural substrates of memory for words can be used as a marker of early episodic memory. The proposed research will explore new methods to test hippocampal structure and function in infants and toddlers ages 18 to 30 months, a period during which episodic memory improves, hundreds of words are being learned, but infantile amnesia operates. Relevance to Public Health: Healthy episodic memory provides a foundation for the emergence and development of autobiographical memory, continuity of self from past to future, and is associated with intellectual ability and academic achievement. The development of episodic memory is impaired following even mild forms of acquired neurological insult, mental health conditions such as anxiety and depression, and neurodevelopmental disorders; language acquisition is additionally impaired in a number of disorders underscoring that a characterization of memory and vocabulary development is key to understanding adaptive functioning in various populations of children.