Piaget (1953) believed object permanence emerges through a series of stages at approximately 18-months. Contemporary researchers have suggested infants achieve object permanence by 3.5-months. A series of studies by Baillargeon (1987) utilized a violation-of-expectation paradigm habituating infants to a paddle moving 180$\sp\circ$. During test trials, a block was positioned in the path of the paddle. During "possible" trials, the paddle moved 120$\sp\circ$, stopped at the block and returned. During the "impossible" trials, the paddle moved 180$\sp\circ$, seemingly through the block. Infants looked longer at the impossible events suggesting an understanding that one object cannot occupy the space of another object contiguously. Looking times could not be explained by detecting perceptual novelty because the impossible event was the more familiar of the test events. Hunter and Ames (1988) have demonstrated that infants look longer at familiar stimuli if they have not thoroughly encoded habituation stimuli. These researchers believed that habituation is a function of time, age, and task difficulty. The current research examines the possibility that infants look longer at impossible events because these events are perceptually familiar. To test whether infants had sufficient opportunity to encode habituation events using the moving paddle paradigm, the number of habituation trials and infants' age were manipulated. Four-month-olds who received 7-180$\sp\circ$ habituation trials looked longer at the 180$\sp\circ$ test event (a significant familiarity preference). Four-month-olds receiving 7-112$\sp\circ$ habituation trials looked longer at the 112$\sp\circ$ test event (a significant familiarity preference). Four-month-olds receiving 12-180$\sp\circ$ habituation events looked significantly longer at the 112$\sp\circ$ test event (a significant novelty preference). A group of 6-month-olds habituated to 7-180$\sp\circ$ trials showed no preterential looking during the test trials. For the four-month-olds, looking times during the test trials were a function of the type of familiarity event and whether there were enough trials to fully encode the habituation events. Looking time was not necessarily a function of an inferred violation of physics. Performance on the moving paddle paradigm might be more easily explained by perceptual mechanisms.

Although it has been hypothesized that children's attention is mediated by their comprehension (Anderson & Lorch, 1983), very little research has examined what toddlers actually understand of what they see on television, mostly due to their limited verbal abilities. Research on the comprehension of other symbolic media (i.e., pictures or scale models) indicates a rapid developmental change between two and three years of age in the realization that a symbol represents something other than itself. Two experiments were designed to non-verbally test whether 2- to 3-year-olds showed a similar developmental progression in understanding the correspondence between television and reality. In Study One, 2-, 2.5-, and 3-year-olds were shown a video of a toy being hidden in a room. Subsequently, they were asked to find the toy. Their performance was compared to that of children who saw the same event through a window. At all ages, children who watched through the window were able to find the toys. Three-year-olds who watched the events on TV were also able to find the toys. Two- and 2.5-year-olds who watched the events on TV were able to find the toy during their first trial but on subsequent trials frequently made an error of going to the location where the toy had previously been hidden. The 2.5-year-olds were able to correct such errors but 2-year-olds had difficulty doing so. In Study Two, 2-year-olds' ability to use televised information was examined with an easier task. They watched on video or through a window as a person placed a toy on a piece of furniture. They were subsequently asked to imitate the toy placement. Performance was again superior after watching presentations through a window than on TV. Two-year-olds performed better with this imitation task than they had with the searching task. Performance was better during the first 2 trials than during the latter 2 trials. The findings from this research indicate that toddlers have some sense of the correspondence between TV and reality. Nevertheless, there are considerable developmental advances in the stability of this understanding between two and three years of age. It was suggested that young toddlers' difficulty with using televised information was due to a weaker representation, requiring them to use alternative strategies. Understanding of the correspondence between television and reality appears to show a developmental progression similar to that seen with other symbol systems, suggesting that there are underlying cognitive changes that are necessary in order for children to be able to understand the representational function.

Infants less than 8 months old appear to lack the concept of object permanence because they fail to search for hidden objects. However, when looking rather than reaching is assessed, infants appear to have object permanence long before 8 months. One explanation for the discrepancy is that young infants lack the means-end motor skill to retrieve objects hidden by covers. The present research tested the object permanence deficit hypothesis against the means-end deficit hypothesis. Direct-reach search tasks were used, which should result in increased search by young infants if the means-end deficit hypothesis is correct. In Experiment 1, 6- and 10-month-old infants were presented with an object visible in water, partly visible in milk hidden in milk, or hidden under a cloth. As predicted by the object permanence deficit hypothesis, 6-month-old infants were less likely to search when the object was hidden than when it was visible or partly visible, but there were no differences at 10 months. The means-end deficit hypothesis prediction that younger infants would be less likely to search when the object was hidden by a cloth than when it was hidden by milk was not confirmed. In Experiment 2, 6- and 10-month-old infants were presented with an object visible behind a transparent curtain, partly visible through a hole in an opaque curtain, partly visible (fit flashlight) under a cloth, and hidden behind a completely opaque curtain. As predicted by the object permanence deficit hypothesis, 6-month-old infants were less likely to search when the object was hidden than when it was visible or partly visible, but there were almost no differences at 10 months. Unexpectedly, measures of locomotor ability were not reliably related to infants' search at 6 months. In a comparison of the cloth event of Experiment 1 and the flashlight event of Experiment 2, half the results indicated that 6-month-old infants were more likely to search in the partly visible event. The results are more consistent with the object permanence deficit hypothesis than with the means-end deficit hypothesis.

Young adults with severe psychiatric disabilities face many significant challenges that put them at risk for being able to transition into adult roles, some of which include: high unemployment rates, the low participation in postsecondary training and education programs, and a strong probability of remaining on public assistance after high school. These young adults also have impairments in the cognitive processing of forethought, planning, and risk assessment—yet most programs do not emphasize the necessary skills and experiences. The purpose of this study is to investigate participants' experiences with education and support to identify the factors that would facilitate their vocational development and recovery. This study used a mixed method research design that involved both quantitative and qualitative measures. The study involved thirty-three participants from the Jump Start program, a career development and mentoring program that matched young adults ages 16–26 with severe psychiatric disabilities with mentors who themselves have had a psychiatric disability. The central research instrument used was an open-ended semi-structured participant questionnaire. There were three quantitative measures that were used: a Demographic Inventory, the Recovery Attitudes Questionnaire (RAQ-7) and the Interpersonal Support Evaluation List (ISEL). In-depth interviews were conducted with seven mentors from the Jump Start program to evaluate the mentoring relationship from their perspective. The study found that many participants prefer specific and tangible learning activities that supported them in taking positive steps in their recovery. Results also showed that interaction with supports was a critical component of their vocational development and recovery. In particular supports involving place, professionals, family, staff and peers played significant roles for the participants. The research also demonstrated that the mentoring relationship made a difference in the lives of both the participants and the mentors. Based on the findings, the researcher recommends three topics for further study. These include: (1) a longitudinal study with a larger sample as an examination of participants' experiences with education and supports; (2) a study designed to identify the variables, which foster young adults readiness to change their behaviors; and (3) a study that looks at what specific factors affects participants' ability to change their behaviors.

Kindergarten, first grade, and second grade students' knowledge of fractions and whole numbers was tested using a number line consisting of whole circles. After a brief training session, students placed displays consisting of circles and pieces of circles on a number line. Kindergarten students did not complete the task correctly. First and second grade students performed better than kindergarten students; however, their performance was related to the training procedure they received. Training with a number line consisting of fractional quantities increased first and second grade students' performance. The findings fail to support the belief that elementary students treat fractions as whole numbers. Instead, the findings provide tentative evidence that task related issues, such as the type of number line used during training, may underlie students' performance on similar number line tasks.

Throughout development, infants are continually adding new skills to their behavioral, cognitive and perceptual repertoire. During the period in which these skills are new, they require some degree of controlled processing, and present the potential to reduce resources available for other cognitive or motor activities. The current study examined the function of attention in managing concurrent demands of cognitive and perceptual-motor processes in 24 month-old children. A primary cognitive task (nonspatial working memory search) was combined with one of three secondary action tasks (requiring high, reduced, or minimal levels of controlled processing), in order to tax attentional resources to the point that performance on the primary search task would suffer. Significant disruptions in search performance were observed with the introduction of a secondary task, but the expected differential interference effects based on level of controlled processing were largely absent. Those conditions which required controlled processing showed no added interference compared to conditions with lessened or no controlled processing requirements. The primary costs to search performance seem to be incurred as children encounter a new task and shift their focus away from the initial task. If children experience any differential effects due to cognition-action resource conflicts, they appear to be masked by the significant effects of disengaging and reengaging with the primary search task.

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In this dissertation, three studies investigate how a person's beliefs about the cues that indicate deception are related to actual accuracy in detecting deception. Based on social cognition research, it was hypothesized that people with accurate beliefs about the cues that predict deception are better at detecting deception only when those beliefs are cognitively available and activated. In contrast, without activation of appropriate beliefs, detection will be no better than for those with inaccurate beliefs. Study I tested this hypothesis in a laboratory study, where participants viewed video fragments of people who are either being honest or dishonest. A questionnaire measured participants' beliefs and the activation of these beliefs was accomplished by manipulating suspicion. Study I provided clear evidence for the main hypothesis, where suspicious participants who had accurate beliefs were better at detecting deception compared to other participants. In Study II, a modified belief questionnaire was administered to 669 undergraduate participants in order to have a better understanding of the attributes of a scale that attempts to measure people's beliefs about the cues that predict deception. Study III attempted to conceptually replicate Study I in a field study. Undergraduate participants watched a video of actual passengers who either were or were not attempting to pass contraband past an experimenter. This study did not show the same pattern of results as Study I, but did show that suspicious participants were better at detecting deception. Study IV attempted to teach and activate the beliefs about cues that predict deception. Either correct or incorrect beliefs were taught to the participants and participants, involvement was manipulated. The main test of the hypothesis in this study did not show an increase in accuracy for participants who were highly involved and given the correct cues, but indirect evidence suggest that belief accuracy may be related to participant's detection accuracy.

Existing research suggests that there is a relation between academic and cognitive ability and externalizing behavior in young children, but the direction of this relation is unclear. The present study tested competing models of the relation between academic and cognitive functioning and behavior problems during early childhood. Participants were 223 children (120 boys, 103 girls) who participated in a longitudinal study from age 3 to 6. A reciprocal model was supported in which early academic and cognitive problems and externalizing behavior predict one another over time, controlling for mothers' education and family stress. When hyperactivity, inattention, and aggression were examined separately with controls, there was evidence that the reciprocal relation was driven primarily by inattention and hyperactivity. No significant gender differences were found. These results suggest that the reciprocal relation between academic and cognitive ability and inattention/hyperactivity is evident early in development, highlighting the need for early assessment and intervention.

The literature on age-related cognitive changes suggests that some older adults may begin to experience cognitive declines resulting in difficulty engaging in adaptive behavior necessary for functional independent living. Understanding the relationship between these cognitive and functional changes will be important for guiding researchers and clinicians in addressing this issue. Many theories regarding the underlying causes of cognitive aging have been proposed. Most causes appear to be related to changes in the efficiency and accuracy with which information is processed. Two current, competing hypotheses of cognitive aging include the processing speed theory of aging and the frontal lobe theory of aging; however, these theories propose two different mechanisms of cognitive change. Processing speed theory suggests that cognitive aging is a bottom-up process in which diffuse declines in a foundational cognitive process impact higher order cognitive functions. In contrast, frontal lobe theory suggests a top down process in that frontal lobe functions decline first and influence other processes in the brain. The current project examined data collected from a large multi-site sample during the Staying Keen in Later Life (SKILL) study. Specifically, the current study investigated both processing speed and frontal lobe theories of aging in an effort to determine which hypothesis best fit the data. It was observed that each model fit the data equally well, thus suggesting that both processes play a critical role in daily functioning. Additionally, the constructs overlapped substantially suggesting that the cognitive constructs may not be as separable as traditionally thought. Finally, the model was invariant across age groups and no differences were observed between young-old, middle-old, and old-old groups.