Proposed legislation in the United States and Canada would require calorie information to be presented on the menus/menu boards of restaurants. To test the possible impacts of such legislation, the present study examined the effects of calorie information on the food selection and intake of restrained and unrestrained eaters. Female students were presented with a menu containing two items, a salad and a pasta dish, for which calorie information was either present or absent. Results of the present study indicate that the provision of calorie information does not alter food choice but does influence the amount people eat. Although the salad and pasta contained the same number of calories, calorie information decreased consumption of pasta, but increased consumption of salad.

The present study investigated the role of differential experience in one’s processing of facial age information. Study 1 examined how differential experience with own- and other-race individuals, as well as differential experience with own- and other-age individuals, influences children’s and adults’ abilities to process facial age information. Study 2 examined how differential sociocultural experiences influence adults’ abilities to process facial age information. The results suggest that the influence of differential experience with own- and other-race faces is most evident when individuals have extremely limited to no experience with other-race faces. There was also a clear other-age effect in young adults’ facial age judgments, presumably due to their extensive experience with own-age peers. However 9- to 10-year-olds and 13- to 14-year-olds also showed an advantage in processing facial age information for young adult faces relative to child and middle-age adult faces. Thus, the 9- to 10-year-olds and 13- to 14-year-olds may have also had the most extensive experience with young adult individuals relative to individuals from other age groups. In addition, results suggest that the efficiency with which individuals process facial age information is influenced by differential sociocultural emphases on the need to differentiate between the facial ages of social partners.

Proposed legislation in the United States and Canada would require calorie information to be presented on the menus/menu boards of restaurants. To test the possible impacts of such legislation, the present study examined the effects of calorie information on the food selection and intake of restrained and unrestrained eaters. Female students were presented with a menu containing two items, a salad and a pasta dish, for which calorie information was either present or absent. Results of the present study indicate that the provision of calorie information does not alter food choice but does influence the amount people eat. Although the salad and pasta contained the same number of calories, calorie information decreased consumption of pasta, but increased consumption of salad.

The present study investigated the role of differential experience in one’s processing of facial age information. Study 1 examined how differential experience with own- and other-race individuals, as well as differential experience with own- and other-age individuals, influences children’s and adults’ abilities to process facial age information. Study 2 examined how differential sociocultural experiences influence adults’ abilities to process facial age information. The results suggest that the influence of differential experience with own- and other-race faces is most evident when individuals have extremely limited to no experience with other-race faces. There was also a clear other-age effect in young adults’ facial age judgments, presumably due to their extensive experience with own-age peers. However 9- to 10-year-olds and 13- to 14-year-olds also showed an advantage in processing facial age information for young adult faces relative to child and middle-age adult faces. Thus, the 9- to 10-year-olds and 13- to 14-year-olds may have also had the most extensive experience with young adult individuals relative to individuals from other age groups. In addition, results suggest that the efficiency with which individuals process facial age information is influenced by differential sociocultural emphases on the need to differentiate between the facial ages of social partners.

The hippocampus, which is a critical brain region for episodic autobiographical memory (AM), is particularly vulnerable to damage following periods of early thyroid hormone (TH) deficiency. Although numerous studies have examined AM performance in adult patients with hippocampal damage, no study has yet examined AM in children exposed to early TH deficiency, such as children with congenital hypothyroidism (CH) and offspring of women who were hypothyroid during pregnancy (HYPO). Given that both animal and human studies have shown that early TH deficiency results in significant hippocampal abnormalities and memory impairments, the purpose of this dissertation was to investigate the effects of early TH deficiency on AM and hippocampal structure and function during childhood. Study I examined AM performance in a large sample of typically developing children and adolescents in order to validate the use of the newly-developed Children’s Autobiographical Interview (CAI). In Study II, the CAI was used to investigate AM performance in children with early TH deficiency (i.e., CH and HYPO groups). Similar to the findings observed in adults with hippocampal damage, CH and HYPO groups both exhibited weaknesses in episodic AM, but not semantic AM, relative to controls. In addition, structural MRI revealed mild bilateral hippocampal volume reductions in HYPO, but not CH, which is consistent with animal models suggesting that early prenatal TH deficiency (i.e., HYPO) may be associated with greater abnormalities in hippocampal structure than postnatal TH deficiency (i.e., CH). Study III investigated children’s AM accuracy performance using a staged event and indicated that children with early TH deficiency had proportionally less accurate recollections of the staged event than controls. Importantly, smaller hippocampal volumes in both CH and HYPO groups predicted lower AM accuracy scores. Finally, in Study IV, functional MRI revealed that children with early TH deficiency exhibited abnormal (i.e., greater bilateral) hippocampal activation during episodic AM retrieval, but not during semantic AM retrieval, relative to controls, which may reflect neural compensation or may be a by-product of the degree of hippocampal damage. Overall, this dissertation provides critical new insight into the long-term effects of early TH deficiency on children’s AM performance and the hippocampus.

Learning and memory are complex phenomena; numerous biochemical and neurobiological mechanisms subserving these functions have been identified. A key molecular component involved in learning and memory, the NMDA-R (N-Methyl-D-Aspartate Receptor) is impaired by MK-801(dizocilpine), an antagonist compound. Here I analyze the effects of MK-801 on the performance characteristics of zebrafish (Danio rerio) as these in turn can significantly influence the outcome of learning tasks. Subsequently, I study the effects of MK-801 on the acquisition, consolidation, and recall of memory in a plus maze, a new task I adapted from zebrafish literature. Although MK-801 seemed to have no effect on acquisition of memory in zebrafish, it disrupted their ability to consolidate and recall in the plus maze, echoing results found in rodent literature. Combined, these results suggest that zebrafish can be used as a tool to further advance the discovery of learning and memory.

Learning and memory are complex phenomena; numerous biochemical and neurobiological mechanisms subserving these functions have been identified. A key molecular component involved in learning and memory, the NMDA-R (N-Methyl-D-Aspartate Receptor) is impaired by MK-801(dizocilpine), an antagonist compound. Here I analyze the effects of MK-801 on the performance characteristics of zebrafish (Danio rerio) as these in turn can significantly influence the outcome of learning tasks. Subsequently, I study the effects of MK-801 on the acquisition, consolidation, and recall of memory in a plus maze, a new task I adapted from zebrafish literature. Although MK-801 seemed to have no effect on acquisition of memory in zebrafish, it disrupted their ability to consolidate and recall in the plus maze, echoing results found in rodent literature. Combined, these results suggest that zebrafish can be used as a tool to further advance the discovery of learning and memory.

The hippocampus, which is a critical brain region for episodic autobiographical memory (AM), is particularly vulnerable to damage following periods of early thyroid hormone (TH) deficiency. Although numerous studies have examined AM performance in adult patients with hippocampal damage, no study has yet examined AM in children exposed to early TH deficiency, such as children with congenital hypothyroidism (CH) and offspring of women who were hypothyroid during pregnancy (HYPO). Given that both animal and human studies have shown that early TH deficiency results in significant hippocampal abnormalities and memory impairments, the purpose of this dissertation was to investigate the effects of early TH deficiency on AM and hippocampal structure and function during childhood. Study I examined AM performance in a large sample of typically developing children and adolescents in order to validate the use of the newly-developed Children’s Autobiographical Interview (CAI). In Study II, the CAI was used to investigate AM performance in children with early TH deficiency (i.e., CH and HYPO groups). Similar to the findings observed in adults with hippocampal damage, CH and HYPO groups both exhibited weaknesses in episodic AM, but not semantic AM, relative to controls. In addition, structural MRI revealed mild bilateral hippocampal volume reductions in HYPO, but not CH, which is consistent with animal models suggesting that early prenatal TH deficiency (i.e., HYPO) may be associated with greater abnormalities in hippocampal structure than postnatal TH deficiency (i.e., CH). Study III investigated children’s AM accuracy performance using a staged event and indicated that children with early TH deficiency had proportionally less accurate recollections of the staged event than controls. Importantly, smaller hippocampal volumes in both CH and HYPO groups predicted lower AM accuracy scores. Finally, in Study IV, functional MRI revealed that children with early TH deficiency exhibited abnormal (i.e., greater bilateral) hippocampal activation during episodic AM retrieval, but not during semantic AM retrieval, relative to controls, which may reflect neural compensation or may be a by-product of the degree of hippocampal damage. Overall, this dissertation provides critical new insight into the long-term effects of early TH deficiency on children’s AM performance and the hippocampus.

To date, research on cognitive aging has treated attention as a unitary resource that operates according to a single mechanism of top-down selection. However, contemporary theoretical models of attention propose that it is a distributed resource, embedded in distinct cortical subsystems, and operates in a manner that reflects the properties of those subsystems. For instance, perceptual attention is thought to originate in posterior sensory subsystems and filter competing unattended input prior to encoding, resulting in early selection of attended information. Executive attention, by contrast, is thought to originate in frontal control subsystems and filter unattended input after encoding, resulting in late selection of attended information. Guided by a distributed resource model, the work described here focuses on how healthy advanced aging influences early selection mechanisms embedded in posterior subsystems, perceptual encoding, and the relationship with frontal subsystems mediating late selection. To examine perceptual attention in isolation, object discrimination tasks were devised in which perceptual competition between repeated objects was manipulated while holding demand on executive control constant. Cortical mechanisms of early selection were probed using functional magnetic resonance imaging (fMRI) indices of neural response and adaptation. Evidence of an age-related impairment in early selection was detected across two fMRI experiments. Unlike young adults, unattended objects not only interfered with perceptual encoding in older adults, but were co-encoded along with the contents of attended input. Age impairments in early selection were also associated with greater reliance on frontally-mediated late selection resources, and, reduced functional connectivity with basal forebrain nuclei. In sum, the results indicate that with increasing age, frontal control subsystems become increasingly encumbered with compensatory redistribution of function from the perceptual cortices, possibly due to loss of central cholinergic integrity. Many well-described age-related deficits of executive attention may therefore represent a consequence of impaired early selection, rather than its cause.

To date, research on cognitive aging has treated attention as a unitary resource that operates according to a single mechanism of top-down selection. However, contemporary theoretical models of attention propose that it is a distributed resource, embedded in distinct cortical subsystems, and operates in a manner that reflects the properties of those subsystems. For instance, perceptual attention is thought to originate in posterior sensory subsystems and filter competing unattended input prior to encoding, resulting in early selection of attended information. Executive attention, by contrast, is thought to originate in frontal control subsystems and filter unattended input after encoding, resulting in late selection of attended information. Guided by a distributed resource model, the work described here focuses on how healthy advanced aging influences early selection mechanisms embedded in posterior subsystems, perceptual encoding, and the relationship with frontal subsystems mediating late selection. To examine perceptual attention in isolation, object discrimination tasks were devised in which perceptual competition between repeated objects was manipulated while holding demand on executive control constant. Cortical mechanisms of early selection were probed using functional magnetic resonance imaging (fMRI) indices of neural response and adaptation. Evidence of an age-related impairment in early selection was detected across two fMRI experiments. Unlike young adults, unattended objects not only interfered with perceptual encoding in older adults, but were co-encoded along with the contents of attended input. Age impairments in early selection were also associated with greater reliance on frontally-mediated late selection resources, and, reduced functional connectivity with basal forebrain nuclei. In sum, the results indicate that with increasing age, frontal control subsystems become increasingly encumbered with compensatory redistribution of function from the perceptual cortices, possibly due to loss of central cholinergic integrity. Many well-described age-related deficits of executive attention may therefore represent a consequence of impaired early selection, rather than its cause.