The relative magnitude of an event (number magnitude) can have direct implications on timing judgments. Previous studies have found that large magnitude numbers are perceived to have longer durations than those of smaller numbers. This bias can be accounted for in several ways; first, the internal clock model theorizes that stimulus magnitude directly interacts with the components of a dedicated cognitive timer by increasing pacemaker speed. Another explanation posits that different quantitative dimensions (space, time, size, intensity and number) are all represented within a common cortical metric thus facilitating interactions within and across dimensions. I have expanded on this framework by proposing that perceived duration is inferred using flexibly applied rules of thumbs (heuristics) in which information from a more accessible dimension (e.g., number magnitude) is substituted for duration. Three paradigms were used to test this theory. First, commonalities in how the intervals separating discrete stimuli of different magnitudes were judged was examined across a variety of quantitative dimensions (number, size, and colour saturation). Perceived duration judgments increased systematically as the magnitude difference between the stimuli increased. This finding was robust against manipulations to sequence direction, and order, suggesting that interval duration was estimated by substituting information regarding the absolute magnitude difference. Second, the impact of number magnitude on sound intensity judgments was examined. When target sounds were presented simultaneously with large digits, they were categorized as loud more frequently, suggesting that participants substituted number magnitude when performing difficult sound intensity judgments in a manner similar to when judging duration. Third, the repetition of magnitude information presented in either symbolic (Arabic digits) or non symbolic (numerosities) formats was manipulated prior to the presentation of a target number, whose duration was judged. The results demonstrated that large numbers were judged to last for longer durations relative to small numbers. Furthermore, context had an effect in which a greater discrepancy in the target’s numerical magnitude from the initial context sequence resulted in a longer perceived duration. The results across all three paradigms suggest that people generally employ information regarding one magnitude dimension (number) when making difficult perceptual decisions in a related dimension (time, sound intensity). / February 2016

Riding's (1991) wholist-analytic dimension of cognitive style proposes a unidimensional view of global-analytic constructs, however, very little empirical evidence exists in support of a relationship between the styles in the wholist-analytic family, which has led to suggestions that style is best conceptualised as a more complex multidimensional construct (Hodgkinson and Sadler-Smith, 2003). Another major problem for Riding's (1991) wholist-analytic style construct is its lack of temporal reliability (Peterson, Deary and Austin, 2003; Rezaei and Katz, 2004; Parkinson, Mullally and Redmond, 2004; Cook, 2008). Furthermore, the current thesis argues that in addition to problems of reliability, the wholist-analytic dimension lacks predictive and construct validity. This thesis outlines two major methodological limitations with the current wholist-analytic ratio measurement, which have raised doubts over the efficacy of the ratio in discriminating between part processing and whole processing style. Firstly, the wholist-analytic ratio is confounded by reflective-impulsive style differences (Kagan, Rosman, Day, Albert and Phillips, 1964). Secondly, the nature of the tasks, combined with strategy preferences, set up an asymmetry in the basis of the wholist-analytic ratio. A new measure of wholist-analytic style, hereafter called the 'Wholist-Analytic Style (WAS) Analysis' has been developed to experimentally manipulate the presentation order of the subtests and the number of parts in the geometric stimuli. Performances on the WAS analysis and the CSA were compared to other styles in the wholist-analytic family to test the unidimensional approach to style. It was found that the wholist-analytic ratio is confounded by sensitivity to reflective style, with much of its discriminatory power being limited to the first subtest, and 6 there is an asymmetry in the part-whole processing basis of the wholist-analytic ratio. Furthermore, there is a consistent relationship between reflective-impulsive style and part-whole processing. This thesis proposes the theory of diminished reflection, which renders the wholist-analytic ratio invalid in its current form. The theory can account for the hereto-unexplained lack of temporal reliability of the wholist-analytic ratio and offers a practical solution to improve both the validity and stability of the ratio. This thesis offers partial support for the unidimensional perspective of style but makes strong links between reflective-impulsive style and part-whole processing preferences.

Eyewitness behaviour is a very important issue in social psychology. Recent years have seen a boom in research in this area; however, very little of this research has addressed the important and fundamental issues raised by the social factors that are involved when eyewitnessing takes place. The present thesis reports research which addresses the effect of social- stereotypic information upon a number of aspects of the eyewitness situation. Of particular interest is the effect of stereotypic information upon the judgment of aggressive and violent actions, and face and body stimuli; on memory for information associated with a dramatic staged incident, when presented either before or after target material; and its impact in an eyewitness interview situation. Finally, an interview technique is designed and tested which aims to reduce the negative impact of stereotypic information on eyewitness memory. Throughout, the impact of stereotypic information presented at encoding and at retrieval is contrasted and compared. The effect of delay between encoding and retrieval is also considered. It is concluded that stereotypic information may affect judgments of information relevant to the eyewitnessing situation whether presented before or after target material. Similarly, stereotypic information may affect memory when it is presented before target material. Little effect is however to be expected on memory when stereotypic information is presented at retrieval, although the exact effects may be found to vary with the nature of the target stimuli used. The source-monitoring interview, based on research by Marcia Johnson and her colleagues, appears a promising means of reducing the distorting effect of stereotypes on memory; particularly when a delay occurs between the encoding and retrieval of target material.

This study examines the nature of parental involvement in the infants' play with objects (toys) and the effectiveness of the various forms of the parent's (mother's) intervention on the infant's cognitive growth. Assessment of the levels of the infants' cognitive competence were obtained through the administration of the Uzgiria and Hunt's "Infants Psychological Development Scales" which provided a formal measure of performance in various tasks that are related to specific areas of sensorimotor intelligence. Videotapes of 15-minute mother-infant play sessions in their homes, involving 6-, 9-, 12- and 15-month-old infants were quantified in terms of maternal and infant categories of behaviour that described variations in the involvement and complexity of the mothers' participation and the cognitive and social components of the infants' orientation to toys in an interpersonal context. Besides this cross-sectional method of data- collection, for each group, a quasi-longitudinal approach was adopted to trace the developmental changes of interpersonal play with objects across a period of three months. Analyses of maternal categories revealed quantitative and qualitative changes in maternal style of interaction as a function of the infant's age, as well as his level of cognitive abilities -relative to age peers. Mothers of 6-manth-olds were different from the mothers in the other groups in that they directed their infants' play into specific channels to an equal extent as their passive participation in the infants' spontaneous manipulative acts. All the other mothers adopted this latter 'enhancing' role to a greater extent than the former 'modifying' one. All mothers engaged in very little structured 'teaching' and very little 'assistance' of their infants. Analysis of the infants' data showed definite developmental changes in all forms of infants' orientation to objects in an interpersonal context. Cooperative play became noticeably more frequent and was more often infant-initiated after age 15 months. Rejection of play with the mother and lack of concentration on the play-task was characteristic of the 9-12 month-old infants. From the data, three conclusions were derived with respect to parental support and its effectiveness. Firstly, parents encourage autonomy and spontaneity in the infant since they 'enhance interaction' with the toys more than they 'modify' it. 'Modifying' is situation-specific in the sense that it increased when the infants' spontaneous manipulations were relatively infrequent, or when they were characterised by a low-level of cognitive complexity, or when the infant was less advanced than his peers on the sensorimotor intelligence scales. However, with age increases the mothers increased their demands from the infants by initiating more tasks for them to reciprocate. The second conclusion is that when the mothers 'modify' interaction they time their activities in accordance with the infants' ongoing behaviour thereby encouraging the infants' attention to the mother and increasing the likelihood of achieving the goal set by her. The third conclusion relates to the effectiveness of parental intervention. Infants whose age was above 9 months seemed to be more dependent on, and more affected by, their mothers' directive intervention. These findings are discussed in terms of the implication for child- rearing practices and pre-school education.

Researchers have found that young children often make "confusion errors" in judging visual stimuli for sameness. That is, children are reported to treat as "just the same" stimuli that are not identical in all respects. Explanations of these confusion errors have focussed on separate aspects of children's performance: language development (e.g., acquisition of relational terms), or perceptual and cognitive development (e.g., visual scanning or selection of criteria! features). The latter appear more successful in explaining the types of errors manifested. For instance, Taylor (1973) found that children, judging sameness among schematic faces, consistently correctly matched particular features and confused others, and later evidence (Wales, pers. comm., 1974) suggested their responses may be affected by the presence or absence of a visual frame around the face .The present series of experiments investigated potential influences on judgments of sameness among sets of schematic faces by children of pre-school and early school age. Variables examined included presence of a visual frame of reference around the face, type of stimulus array, task requirements, and salience of stimulus features relative to each other. Initial results confirmed that, in tasks like matching-from-sample or pair-comparison, children systematically matched only certain features of the faces and confused other features. Type of task (including stimulus and response variables) and presence/absence of a visual frame interacted with each other to influence the response patterns. Subsequent experiments suggested that neither objective visual salience of one stimulus feature over another, nor selection of a visual criterial attribute, satisfactorily accounted for the observed response patterns. A more likely contributor was subjective weighting of features on grounds of their contextually-afforded significance. Faces were not compared feature-by-feature; instead, the criterion seemed to be sameness of affective expression conveyed. It is argued that many of the confusion errors were not due simply to linguistic or perceptual immaturity. Rather, in circumstances where adults take "same" to refer to identity across all features, the children took it as "same kind of thing": their responses reflected their bases for classifying the faces (i.e., by affective content) rather than ability to judge identity. Having judged unidentical faces as the same, a considerable number of children indicated in justifying their judgments that while certain features were the same, others were not. Thus they appeared able to understand and use "same" in its various adult senses, but interpreted the task instructions differently from adults.

During aging, a decline in metabolism appears to be associated with altered hippocampal function. Thus, 1-13C-glucose and 2-13C-acetate were employed to assess neural metabolism in the dentate gyrus and CA1 of F344 rats with respect to aging and cognitive status. The results obtained when 1-13C-glucose was used as the metabolic substrate suggest that glucose metabolism may not be altered in neural tissue itself with respect to aging or a decline in hippocampal function. In contrast, the use of 2-13C-acetate, a substrate that is preferentially metabolized by astrocytes, revealed significantly increased astroglial metabolism associated with age and preserved hippocampal function. Specifically, greater 2-13C-acetate incorporation into glutamine and glutamate was observed in the dentate gyrus and CA1 of aged rats that performed similar to young rats in the Morris water maze task. Since glutamate is the primary excitatory neurotransmitter of the hippocampus and plays a central role in synaptic plasticity, the mechanism proposed to underlie learning and memory, these finding were taken to represent an adaptive metabolic response by astroglia in the aged hippocampus. Subsequently, astroglia metabolism could potentially be a future target of therapeutic strategies for age-related cognitive decline.

The impact of pain intensity upon tasks of attention and memory was investigated, with the specific aim of evaluating differences in effortful versus automatic processing, implicit versus explicit memory, and right versus left hemisphere measures. All research participants in the study had been diagnosed with chronic pain conditions and each person completed memory and attention tasks, measures of intelligence, emotional functioning, and cognitive failures, and provided pain intensity ratings. Ratings regarding level of fatigue, quality of sleep, perceived control over pain, and perceived effect of pain on attention and memory were also obtained. With age, education, fatigue, and self-efficacy controlled, performance on the cognitive tasks was used to predict pain intensity through a series of hierarchical multiple regressions. Performance on the cognitive tasks was not able to account for a significant amount of the variance in pain intensity. Self-efficacy and fatigue were also noted as strong predictors of pain intensity among this sample. Implications are discussed in view of rehabilitation and neuropsychological assessment of persons with chronic pain, as well as clinical interventions with this population. / Graduate

This thesis addressed the question of whether global, 'executive' control processes are involved in switching between discrete cognitive tasks. The involvement of executive working memory processes in the control of switching was examined, using a combination of cognitive and cognitive neuropsychological methods. In all studies, participants switched unpredictably between two simple tasks, and in some cases they also performed concurrent tasks. The focus throughout was on two putative areas of executive control that may influence task switching, goal-directed advance processing, and the suppression of interference between tasks. The first series of experiments explored whether the central executive of working memory is required to prepare for a task switch, but found no evidence that this is the case, whether an endogenous or an exogenous method of task cueing is used. The possibility was then raised that cognitive control does not just operate when the task switches, and a further study showed that this is, indeed, the case. However, two experiments using different task cueing methods did not reveal any evidence that executive processes in working memory carry out this control. It did, however, appear that the central executive is required for overall task performance, as opposed to task switching, when the method of cueing requires that participants keep track of and update information about which task is to be performed. The final study examined task switching and executive function in a group of patients with damage to the frontal lobes, and to posterior areas of the brain. Although a number of participants showed evidence of executive deficits, they had no difficulty in switching in a speeded response task. In conclusion, it is argued that local, rather than global, control processes are involved in switching tasks in the present paradigm, and implications are discussed for theories and investigation of executive control. 2

This study was designed to inform theoretical and clinical understanding of the relation between executive function and metacognition in late adulthood, and to examine the effects of Parkinson's Disease (PD) on these aspects of the executive control system. The sample included two groups of neurologically intact (NI) participants and one group of participants with PD. All participants were over the age of 55 years and screened for dementia and depression. The NI young-old group included 22 participants between the ages of 56 and 74 years of age. A second group of 20 participants, between the ages of 75 and 90 years formed the NI old-old sample. The third group included 20 nondemented participants between the ages of 55 and 84 years with a diagnosis of PD. First on measures of executive function, memory, and motor performance significant age-related differences were limited. Tasks measuring the ability to generate novel concepts and to execute target motor movements revealed a significantly lower level of performance for the NI old-old participants, relative to their younger counterparts. While age-related differences in performance did not reach significance on the remaining tasks, the mean scores for the NI young-old group were slightly higher. The participants with PD had a lower level of performance than the NI groups in all three measured areas of functioning. Second, the three measures of metacognition, performance predictions, postdictions, and data each yielded distinctive results. The accuracy of predictions was largely resilient to the effects of aging. However, the prediction accuracy of the PD participants was lower on measures of memory and gross motor performance. Groups were equivalent on measures of postdiction accuracy across measures, with the exception of the handwriting task where the NI groups showed a higher level of accuracy than the PD group. Perceptions of daily memory functioning were similar for the three groups. However, the participants with PD reported more motor problems than those reported by the NI groups. Third, the results confirmed the theoretical relation between executive functioning and metacognition in the areas of memory and fine motor control, but executive function was found to have little impact on a more routine gross motor task. The relation between executive function and metacognition appears to be domain-specific, with a stronger association on cognitively-laden tasks relative to tasks of a more routine nature. / Graduate

This thesis extends previous research on critical decision making and problem-solving by refining and validating a self-report measure designed to assess the use of critical decision making and problem solving in making life choices. The analysis was conducted by performing two studies, and therefore collecting two sets of data on the psychometric properties of the measure. Psychometric analyses included: item analysis, internal consistency reliability, interrater reliability, and an exploratory factor analysis. This study also included regression analysis with the Wonderlic, an established measure of general intelligence, to provide preliminary evidence for the construct validity of the measure.