The purpose of the present study was to examine cognitive abilities and problem solving processes of young and older adults. Specifically, three areas of inquiry were investigated: possible age-related differences in problem solving cognitive abilities, possible differences in cognitive processes used during problem solution, and possible differences in determinants of problem solving cognitive processes.

Includes bibliographical references (leaves 349-421) Addresses some of the mechanisms which may potentially contribute to the physiological anorexia of ageing, as suggested by previous animal and human studies.

Reprints of the author's previously published articles included as an appendix. Bibliography: leaves 165-188. "This thesis describes a series of experiments that aimed to investigate the effects of folic acid deficiency and defects in folate metabolism on chromosome damage rates in human lymphocytes. The accumulation of chromosome damage over time is an important issue because it is thought to contribute to the mechanism of ageing and the aetiology of diseases of age such as cancer and Alzheimer's disease."

Reprints of the author's previously published articles included as an appendix. / Bibliography: leaves 165-188. / xiv, 189 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / "This thesis describes a series of experiments that aimed to investigate the effects of folic acid deficiency and defects in folate metabolism on chromosome damage rates in human lymphocytes. The accumulation of chromosome damage over time is an important issue because it is thought to contribute to the mechanism of ageing and the aetiology of diseases of age such as cancer and Alzheimer's disease." / Thesis (Ph.D.)--University of Adelaide, Dept. of Physiology, 2002?

A relatively new phenomenon in learning research called highlighting occurs when participants show a seemingly irrational preference to attribute a stronger cue-outcome association to a later presented perfect predictor when it is paired with an imperfect predictor than that of an earlier presented perfect predictor paired with the same imperfect predictor (Kruschke, 1996). Current research suggests that the highlighting effect depends on the ability to learn to shift attention away from an irrelevant cue toward a more relevant cue in order to reduce errors in causal judgment and preserve an earlier formed association (Kruschke, 2003). Much research has suggested that older adults have difficulty disengaging attention from irrelevant information, which could be problematic in the highlighting procedure (Cohn, Dustman, & Bradford, 1984; Tipper, 1991; Mutter, Naylor, & Patterson, 2005). However, the results of the current experiment suggest that older adults can learn attentional shifts in order to guide associative learning and reduce errors in causal judgments. These data prove to be a problem for many models of associative learning (e.g., Mackintosh, 1975; Rescorla & Wagner, 1972; Van Hamme & Wasserman, 1994), but support a model proposed by Kruschke (2006).

This study examined the behaviors relating to the utilization of prescription and over-the-counter medications in a small group of elderly subjects in the 65 years and over age range. This group was attending an Elderhostel at Western Oregon State College during the summer of 1991, when the information was obtained. The objectives of this study were to ascertain specific medication taking behaviors, and whether or not directions were adhered to as prescribed by physicians for this highly educated group, or if their behaviors were similar to those referred to in the literature for all elderly. A sample of 38 elderly was obtained during an Elderhostel Wellness Vacation at Western Oregon State College in Monmouth, Oregon during July, 1991. Subjects completed questionnaires regarding medication-taking behaviors as part of a wellness class session regarding the safe use of medications. Questionnaires were filled out prior to the class discussion. Data were assembled using one survey instrument with questions relating to medication usage. Descriptive statistics using histograms showing frequency distributions were used for data analysis. Sixty-five percent of this group were taking prescription medications and sixty-eight percent of this group were taking over-the-counter medications. Medications were being obtained from more than one physician and more than one pharmacy. The subjects took fewer doses of medications per day and less medication per dose than prescribed. Medications were discontinued prematurely if feeling better or worse. Leftover medications from previous prescriptions were being taken. Outdated or expired medications were being taken. Alcoholic beverages were being used in conjunction with the use of prescription medications. In some cases, prescriptions were not filled because they were considered to be unnecessary. Recommendations for education and future research in the problematic area of drug use in the elderly include: 1) More time spent by health care professionals to educate the elderly in the correct and safe use of medications; 2) Community health promotion programs targeted at the well elderly; 3) Personalized "brown bag" medication counselling sessions; 4) Medication education programs at Elderhostels throughout the country; 5) Education programs through the American Association of Retired Persons; and 6) Further studies of larger groups of well-educated, healthy and active elderly. / Graduation date: 1993

Distinctive encoding is the processing of unique item-specific information in the context of more general relational or organizational information. It enhances memory performance for both younger and older adults (Smith, 2006). The current work examined how adults use distinctive encoding to aid their free recall performance and whether task experience alters subsequent use of a distinctive encoding strategy. At study participants saw a series of five-item taxonomically categorized lists (e.g., FRUITS). They were first required to generate a category-consistent label (e.g., TASTY FRUIT). In the guided condition, they were then required to generate a single word representing either (1) another category-consistent characteristic (e.g., GROWS) or (2) a characteristic that distinguished a study target from the other items (e.g., FUZZY for the target KIWI). In the self-initiated condition, participants were allowed to select an encoding strategy on their own. After test, all participants completed a second study-test phase with self-initiated strategies. Younger adults initially rated distinctive encoding as more effective, relative to relational encoding, than did older adults, and this difference persisted after test experience, indicating an age difference in learning about the relative superiority of distinctive processing. Consistent with these ratings, distinctive encoding was implemented more so by unguided younger adults than older adults in phase 1. However, both strategy use and recall performance were similar across age and study conditions in phase 2. Both older and younger adults were capable of utilizing distinctive encoding effectively following task experience, although perceptions of strategic effectiveness did not always correspond to self-initiated study behaviors.

Information in a message can either be fully expressed (explicitly) or indirectly stated (implied) and understood by inference or association. Previous research suggested an age-related decline in performance of implicit compared to explicit information and that this relationship is moderated by prior knowledge. Whereas previous studies mainly obtained quantitative data of inferencing performance, the current study employed both quantitative and qualitative techniques to understand age-related differences in inferencing. Twenty younger and older participants evaluated whether a series of one-sentence statements were true or false based on specific two-sentence text passages. Text passages either resembled real warnings (taken from actual products) or were novel (the opposite of a warning found on an actual product). Statements either explicitly stated information from the text passage or required participants to go beyond information given in the text. Quantitative analysis showed that older adults accuracy compared to that of younger adults when evaluating real text passages, with explicit items being evaluated more accurately than implicit items. For novel text passages (generally lower accuracy scores), younger adults showed the same pattern as for real text passages, whereas older adults accuracy was low for both explicit and implicit statements. Qualitative analyses supported that participants correct answers generally reflected that the intended inference was drawn and that for incorrect answers the inference was not mentioned. The data also suggested that accuracy scores may underestimate the actual ability to infer. Both age groups mentioned most often that text-related factors (e.g., clarity) influenced their decision and brought outside information (e.g., education, experience, expectations) to the task regardless of text passage or statement type. Older adults more often referred to outside information than younger adults, particularly when evaluating novel text passages and their answer was wrong. This study substantiated that age-related differences in a task requiring inferencing may be explained by a combination of the factors of working memory (time and availability of information) and prior knowledge as well as a possible decline in inferencing ability. Prior knowledge is important for both age groups and especially so for older adults. Important implications for designers are to make information available and explicit.

This project introduces a judgment of source learning (JOSL), an evaluative judgment by which participants make predictions about their ability to remember the source or modality of stimuli in the future (at test). The JOSL is an open-ended judgment that encapsulates a) participants confidence in the information they are able to retrieve at the time of the judgment, b) participants confidence in the strategy that they are using for retrieval, and c) participants confidence in how effective their current retrieval and monitoring strategies will be in the future. Younger and older adults studied a paired associate list comprised of unrelated text-sound, or text-picture stimuli. They provided judgments of learning for paired-associate memory (JOLs), and some provided judgments of source learning for target source memory (JOSLs). Participants also provided strategy reports for study. JOSLs did not reliably predict source recall, and level of source recall varied as a function of target type rather than condition. Age differences were found in JOL resolution, where younger adults were more accurate in their prediction of future paired associate memory than older adults. Confidence gammas showed that both younger and older adults could reliably identify which items they answered correctly; however, the confidence gamma for source recall of sound targets was reliably negative, mostly likely a result of a PICTURE response bias and overconfidence in wrongly source attributed sound targets.

Thesis (Ph. D.)--University of California, San Diego, and San Diego State University, 2004. / Vita. Includes bibliographical references (leaves 47-50).