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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Hemispheric asymmetries in the attentional blink

Holländer, Antje January 2004 (has links)
The attentional blink (AB) refers to a decrement in detecting the occurrence of a probe item if it closely follows a previous target item in a stream of stimuli in rapid serial visual presentation (RSVP). In a series of experiments I investigated the question of hemispheric asymmetries in the AB. Experiment 1 was a simplification of the experiment by Raymond et al. (1992) to determine whether the particular stimuli and task conditions of my study would produce an AB. In Experiments 2 and 3, two RSVP streams were presented in parallel, one in each visual field. The AB occurred only when participants both identified and located the target, and not when they simply located it. When targets and probes were both presented in the right visual field (RVF), the typical AB pattern was obtained, sparing probes in the first post-target location ("lag 1 sparing"). However, the AB was greatly attenuated when both target and probe were in the left visual field (LVF). When target and probe were in different spatial locations, there was a strong decrement in detecting the probe in the first post-target position-again more marked in the RVF. Cross-stream decrements may reflect the transient effects of shifting attention, while the AB itself appeared to be largely restricted to within-stream sequences, and to processing by the left cerebral hemisphere. Experiment 4 was a further behavioural study, in which I examined differences in functional cerebral asymmetries modulated by gonadal steroid hormones during the menstrual cycle in women. Twenty-one right handed women, with regular menstrual cycle, were tested with a double RSVP task (one stream in each visual field) during the low steroid menses and the high steroid midluteal phase. An AB was obtained bilaterally in the midluteal phase, while during menses the probe detection deficit was evident only in the RVF. Low steroid levels appeared to stabilize functional cerebral asymmetries. In contrast, high levels of estradiol and progesterone in the midluteal phase appeared to reduce functional asymmetries due to a selective enhancement of the AB in the right hemisphere. In Experiment 5 and 6 I recorded event-related potentials (ERPs) to examine the temporal course of the AB. probe-related ERPs were compared between the control condition and the experimental condition when the probe was presented in the blink period (post-target position 2-4) and in the no-blink period (post-target position 6-8). In the control condition in which the subjects were told to ignore the target, there was a negative peak around 300 ms following the probe, regardless of whether the probe was presented during the blink phase or during the no-blink phase. The same peak was found for the experimental condition when the probe was presented during the no-blink phase, but was missed for probes presented during the blink phase. This finding provides strong evidence that the AB reflects an impairment in a postperceptual stage of probe processing, probably at the stage of working memory. I replicated the finding (Vogel, Luck, & Shapiro, 1998) that the AB and the P3 elicited by the target component are related. Source localisation of electrophysiological activities using low-resolution electromagnetic tomography (LORETA; Pascual-Marqui, Michel, & Lehmann, 1994) revealed reduced activation during the AB in the left cerebral hemisphere when letters were used as stimuli, whereas the right hemisphere showed reduced activation when symbols were used. / Whole document restricted, but available by request, use the feedback form to request access.
82

Central auditory processing in children with a history of neonatal jaundice

Greville, K. A. January 1990 (has links)
An experimental group (Group A) of 22 children around 7 years of age who had normal hearing for pure tones but who had experienced neonatal jaundice with peak bilirubin levels of at least 300 µmol/l was tested on a range of audiological tests selected to assess aspects of their central auditory processing. Children who had not been tested for bilirubin level were selected as control subjects (Group B); they were matched on the variables gender, race, gestational age, birthweight, Apgar scores and occurrence of respiratory problems. A smaller experimental group, Group C (n=7), with peak bilirubin levels between 250 and 299 µmol/l but with perinatal complications was also studied. The experimental groups had higher mean acoustic reflex thresholds and lower mean reflex amplitudes than the control group. Acoustic reflex threshold patterns of abnormality consistent with central dysfunction occurred in two children from the main experimental group and two children in the control group. None of the children from Group C showed abnormal reflex thresholds. Acoustic reflex amplitude patterns of abnormality consistent with central dysfunction were present in six children from Group A and two children from Group C, compared with three children from the control group. Masking level differences were absent in five subjects from Group A and three children from Group C, compared with three control subjects. No group differences were evident for ABR latency or amplitude measures, but poor morphology or repeatability of wave V was observed in ten subjects from Group A and three children from Group C, compared with five children from the control group. A larger number of failures within the experimental groups was found for two of the four speech tests, that is, for interrupted and filtered speech tests, but not speech in noise or competing words tests. Five children from Group A (but none from Group C) performed poorly on the interrupted speech test, compared with two from Group B. The filtered speech test was failed by six children from Group A and two children from Group C, compared with two from Group B. Parental reports of behavioural or learning disorders were distributed equally among the groups and were not associated with particular patterns of test failure. Overall, children in the experimental groups failed significantly more tests of central auditory functioning than did children in the control group (F(2,48)=5.5,p<.01). The results were interpreted as implicating jaundice in long-term central auditory processing abnormalities.
83

A Quantitative and Qualitative Analysis of Women’s Body Image: Comparisons Between Normal Weight, Overweight, Eating Disordered and Body Building Women

Hammond, Kay Maree January 1996 (has links)
This thesis approaches the area of women's body image with the aim of expanding existing knowledge based on traditional male/female comparisons of how women respond to quantitative measures of body image. It does so by distinguishing between some different body-type groups of women. These were mostly Caucasian women aged eighteen and over who lived in the greater Auckland area. They were grouped as: normal weight (n=43); overweight (n=37); women with eating disturbances (n=27); and body builders (n=17). A pilot study involving ten normal weight women examined the face validity of several established international measures of body image as well as additional ones developed for the main study. The established questionnaires were: the Rosenberg Self Esteem Scale, the Body Esteem Scale, the Weight Locus of Control Scale, a Figure Rating Scale and a Silhouette Rating scale. The newer measures consisted of modifications made to the Figure Rating Scale and the Silhouette Rating scale. Verbal questions about teasing history were also asked, the intention being to formulate a teasing history questionnaire for the main study. These measures were found to be valid by the women. In part one of the main study quantitative comparisons between the groups revealed some differences, but also some surprising similarities. Desirable body types of normal weight and muscular physique were described positively in physical and personality terms. The undesirable body types of thin and overweight received negative descriptions irrespective of the women's own group membership. The eating disordered women scored the lowest self-esteem while the other groups did not differ. The body builders scored the highest body-esteem while the normal weight and overweight, and overweight and eating disordered groups did not differ. Correlations between self-esteem and body-esteem were significant for all groups except the body builders. The correlation was strong for the eating disordered group and moderate for the normal weight and overweight groups. In the Figure Rating Scale the body builders chose more muscular ideal figures than the other groups and for all groups the ideal and current figures were usually one figure size different. At least half the women in each group felt their body was the same size as they thought it was' Of those remaining who gave different answers to the think versus feel ratings, nearly all in the eating disordered group reported they felt bigger. In the other groups there was an even split between those who felt bigger and those who felt smaller than they thought they were. The women were most united in their selection of the figure they thought men would find most attractive. In approximately a quarter to one third of each group (excluding the body builders due to small numbers) the figure selected as attractive to men was also chosen as the self ideal. Approximately a quarter of each group [excluding body builders) selected the same self ideal and peer ideal, however a considerable percentage of women selected a larger self ideal than peer ideal. All groups reported there should not be an ideal figure at all in society. All groups tended to believe that their weight was under their own control. Most women reported having been teased about their appearance and being affected by this teasing. This was especially noticeable for the eating disordered group, a considerable percentage reporting they still felt adversely affected by it. Part two of the study introduces feminist poststructuralist theory and the Foucaultian concept of power and discourse analysis as ways to explore body image research. The body image literature introduced in part one is then revisited showing how this area of research can be harmful for women. The presentation of the interviews with 28 women follows, seven women from each body type group. A short form of discourse analysis was used for the women's responses to issues in body building, their explanations of the self-esteem, body-esteem, and the results of the correlation of the two. Issues related to the presence of an ideal figure size in society are also discussed. A longer form of discourse analysis was involved for the readings of the women's accounts of having been teased about their appearance. These readings showed many women located their accounts of teasing within a discourse of trivialisation-of-teasing, indicating that the seemingly trivial practice of teasing is a powerful form of social control, resulting in feelings of vulnerability. The study concluded with summaries and conclusions from the literature presented in the introductions of both parts one and two. The quantitative and qualitative research methods were compared to see what both could offer body image research. Finally speculations were made about directions which body image research could take at both the individual and cultural level.
84

Assessment of the quality of observers' records of behaviour

Mudford, Oliver Charles January 1990 (has links)
The measurement of behaviour by direct observation may be improved when observers have been provided with equipment which enables real-time recording. There are no data available concerning the quality of this type of measurement. Indeed, there is no consensus among researchers as to appropriate methods of quality assessment. In the present series of studies, observers were provided with hand-held computers programmed to act as real-time recorders. The quality of their records was assessed by three "traditional" methods, representative of those which have been used most frequently in previous behavioural research: interobserver agreement, observer/criterion agreement, and relative error. An instrument calibration procedure, the standard method for measurement accuracy analysis in the natural sciences and engineering, was demonstrated for comparison with traditional methods. The traditional methods were found to be unsatisfactory for theoretical and empirical reasons. The calibration procedure was shown to have some considerable potential advantages for applied behaviour analysis. Disadvantages, both statistical and practical, were also discussed.
85

Young people's reactions to nuclear issues : a constructivist analysis

Oliver, Pam, 1949- January 1992 (has links)
The 1980s saw an increasing interest amongst psychologists, both as researchers and as practitioners, in the ways in which people react to nuclear weapons issues, especially the perceived threat of nuclear war. Much of the research in relation to "nuclear threat", undertaken either within the United States or by United States psychiatrists in collaboration with European colleagues, and using extensive questionnaire surveys, focused on the fears of children and teenagers. Some researchers concluded that large proportions of young people were at risk of impaired psychological development because of nuclear threat which resulted in a pervasive sense of futurelessness and a distrust of .adults. This research has been widely criticised since because of apparent researcher bias in the methods used, interpretations offered, and general paradigm. I also found much of the research ethically objectionable. My research has involved 52 interviews with young New Zealanders and administration of a questionnaire to more than 2000 others, including ages nine to 18 and three ethnocultural groups, as well as interviews with some teachers. The objectives of these studies were: (1) to produce detailed information about how young New Zealanders react to nuclear weapons issues which might be used by educationalists, mental health professionals, parents, and young people themselves in dealing with those issues; (2) to make specific recommendations about young New Zealanders' apparent needs and preferences for learning about and dealing with nuclear weapons and related issues; (3) to provide a detailed methodological comparison of interview and questionnaire approaches to this research topic, and discuss issues of theory and paradigm; and (4) to comment on ethical and practical issues for both the researcher and the researched in undertaking research on emotive and potentially distressing topics, especially with young people. As a result Chapter 1 of my thesis contains a comprehensive critical review of the international research and theory relating to young people's perceptions of nuclear weapons, examining the problems of method, interpretation and paradigm associated with this area of research. Both interview and survey data are presented in relation to: (a) young people's levels of awareness and sources of information about nuclear issues; (b) their emotional, cognitive and behavioural reactions to nuclear issues, including coping strategies and activism: (c) their perceptions of the future; (d) comparisons across gender, age and ethnocultural group; (e) the role of adults; and (f) differences between New Zealanders and other national groups. The data are discussed in terms of: (i) their patterns, contexts and meanings; (ii) their implications for peace and global issues education; and (iii) their implications for research method, including ethical issues. Recommendations are made for how psychologists and others can help young people and adults in dealing with global and social threats, including how to undertake research which is empowering as well as valid and useful.
86

Performance in multiple schedules

Charman, Lesle Frances January 1983 (has links)
Four experiments are reported. Each experiment investigated a different variable which at sometime has been thought to influence performance in multiple schedules. Variable-interval schedules were used in all experiments and twelve pigeons served as subjects, six in the first two experiments and six in the third and fourth. The parametric data provided by each experiment were analysed using the generalized matching law and comparisons with findings in concurrent-schedule research were made. In Experiment 1 the effects of component durations and component reinforcer rates on multiple-schedule performance were investigated. Component duration did not affect sensitivity to the ratios of reinforcer rates. In Experiment 2 the effects of food deprivation and component reinforcer rates on multiple-schedule performance were investigated. Sensitivity to the ratios of reinforcer rates increased as deprivation was reduced. However, the data could only be explained by a model which assumed no direct component interaction. In Experiment 3 the discriminability of the stimuli customarily used in multiple-schedule research was investigated. The stimuli were perfectly discriminable. It was shown that the undermatching of response and reinforcer ratios typical of multiple-schedule performance was not the result of a failure to discriminate the stimuli signalling the components. In Experiment 4, a procedure for investigating time allocation in multiple schedules was introduced. The birds could switch in to the component in effect, and the components alternated at three minute intervals. Each switch in to a component gave acess to the schedule in effect for fixed brief periods. Ratios of component response rates showed typical multiple-schedule undermatching. However, a commonality in concurrent and multiple-schedule performance was revealed in respect to local or switched-in response rates. In both types of schedule, it appears that pigeons allocate time so as to equalize the local response rates. It is apparent that the differences reported between concurrent and multiple-schedules with respect to the sensitivity with which responses are distributed between the components as a function of the distribution of reinforcers are a result of the constraints imposed on the subjects' allocation of time in multiple schedules.
87

A Rhetoric of mysticism

Adams, Peter James January 1991 (has links)
Research into mystical experience has to date relied primarily on retrospective self reports of mystical states. Analysis of such reports assumes a direct correspondence between their content and the content of the experiences. But experiencers themselves often express dissatisfaction with the capacity of language to convey these states, and the language they do choose to use is typically vague and ambiguous. The current dissertation argues that vagueness is not an accidental nor an unfortunate feature of mystical communications. Because of difficulties in direct expression, mystical communicators rely on the active and imaginative participation of the listener/reader to complete the expression. A theory of provocative gaps is developed to explain how this operates. A "gap" is conceived of as an open receptacle in linguistic space. It provides a site within a discourse upon which receptive listeners/readers can insert content from their own experience. Gaps can be created by blatant omissions of content, but in written descriptions are more likely to occur in indirect forms by exploiting subtleties in grammar and meaning. A simple diagrammatic system is developed for explaining the gap-provoking potential of several major rhetorical strategies. Three studies were designed to explore whether and at what frequency written testimonials of mystical experience exploit a selection of 31 of these gap-provoking strategies: the first study exposed their high frequency in extracts by well-known published mystics; the second indicated similarly high frequencies for the average person's description; and the third found significantly higher rates in mystical testimonials than in descriptions by the same participants of dream or travel experiences. A similar use of vagueness can be found in the language of hypnotic trance induction, and as an adjunct to the second study, the hypnotic susceptibility of 81 subjects was assessed and results indicated that subjects with mystical inclinations were more susceptible to hypnosis than those without. The general support of the studies for a theory of provocative gaps suggests that the notion of intentional vagueness could have useful application in the study of other types of communication, including: the media, art criticism, teaching, psychotherapy and academic discourse. / Whole document restricted, but available by request, use the feedback form to request access.
88

An evaluation of three treatment programmes for alcoholism: an experimental study with six- and eighteen-month follow-ups

Howden-Chapman, Philippa January 1984 (has links)
To evaluate the efficacy of a typical range of New Zealand alcoholism treatment programmes, 113 male and female alcoholics were randomly assigned after inpatient detoxification to one of three programmes that provided decreasing amounts and intensity of treatment: a six-week inpatient programme, a six-week outpatient programme, and a single confrontational interview where patients were referred to non-hospital services. Those who refused or dropped out of treatment were followed up in a semi-control group. A broad range of patient measures were taken at intake and 6 and 18 months afterwards, when 86% of subjects were located. No treatment was more effective than another (in terms of statistically significant differences) in helping subjects to abstain or drink less, nor did any treatment appear to be more effective than another in promoting social and psychological recovery. Furthermore, those who stayed in treatment did not show significantly more long-term improvement than those who refused or dropped out of treatment. Two programmes did significantly reduce the alcohol consumption of the alcoholics assigned to them at the 6-month follow-up compared to those who dropped out, but by 18 months there was no longer a significant treatment effect. Although the two follow-ups showed individual drinking patterns were unstable, on average almost half the subjects located had improved either because they had abstained or were drinking moderately. There were only small gains on direct measures of social adjustment. Compared to the general New Zealand population, subjects were more likely to be divorced or separated, manual workers and unemployed. Nonetheless, these characteristics did not contribute to predicting the subjects' response to treatment. Multiple regression equations explained between 33% and 57% of the variance in amount drunk after treatment. The patients' own predictions of their chances of drinking again, evidence of electrocardiographic abnormalities and the patients’ net weekly incomes, were more consistent variables in explaining drinking levels and predicting abstinence in the long term than the demographic and psychological variables. Variables that were significant in explaining drinking levels were often not significant when it came to predicting abstinence and vice versa. Abstinent subjects felt more often than drinkers that they had achieved the goals that they had set themselves aria by the final follow-up there were many positive differences in lifestyle apparent. Thus, in the final outcome, although abstinence was clearly demonstrated to be a worthwhile goal, no treatment was significantly more effective than another in helping to achieve this goal. Patients who underwent treatment apparently showed greater recovery than those who dropped out of treatment but this result was also not statistically significant.
89

Children's understanding of sexual orientation

Saphira, Miriam Edna January 1990 (has links)
In 1989 New Zealand is considering legislation which will make discrimination against lesbians, transexuals and gay men illegal. To increase children's understanding of sexual orientations educators need to have some knowledge of what children already understand and how children use their information. The three studies address this issue in spite of the difficulties in obtaining permission to ask children about homosexuality. A homophobia questionnaire was administered to 290 first year psychology students. They were also asked to recall their childhood feelings about gay people when they first met a homosexual and first understood the concept of homosexuality. Older women were the least homophobic. A second study was carried out with 5, 7, and 11 year old children in three schools with a family discrimination task. A third of the 11 year olds could label the couples of the same sex as gay, homosexual or lesbian and gave more positive items to the two-parent families. A third study involved 31 children from two-parent families and 32 from lesbian families. Out of the 63 six to ten year olds, 27 could define 'homosexual' and 'gay' and 37 could define lesbian. Twenty could use a strategy to recognise a lesbian. Although social discrimination against non-heterosexual orientations placed some constraints on this research, it yielded preliminary evidence for the emergence of children's understanding of sexual orientations between 7 and 11 years of age.
90

Locomotion experience, age, familiarity, and the use of the social referencing strategy in infancy

McComas, Katherine Joan January 1989 (has links)
Researchers and theorists have stressed the importance of self-produced locomotion for the development of more distal forms of communication such as social referencing but this notion has not been specifically tested. Social referencing research has also been conducted exclusively in the university laboratory. Three studies examined the influence of self-produced locomotion on the development of social referencing and compared social referencing behaviour in familiar and unfamiliar settings. Social referencing was defined as occurring when, following a novel event, infants looked to a familiar adult and used the information provided by the adult to adjust their behaviour towards the event appropriately. In the first study, forty infants, half locomoting and half non-locomoting, were seen in their own homes at either 7-months (10 crawling, l0 not crawling) or 9-months (10 crawling, l0 not crawling). Testing was repeated on all infants 2 months later. Infants were videotaped in each of three maternal availability conditions (mother available; not available; or not interactive) before a remote control toy car moved toward them. Mothers were instructed to give either a positive or negative facial signal when their infant looked at them during this final phase. The infants were responsive to the availability of the mother on a number of dependent measures. Locomoting infants approached their mothers more, played with the toys less, and differed in some aspects of looking behaviour during the availability phases. During the final social referencing phase neither group consistently used the information provided by the mother to change their behaviour. A second study examined a further ten, 9-month-old infants using an identical procedure. The infants were delayed in the onset of self-produced locomotion due to surgical and immobilization procedures prescribed for club foot. This group did not differ from the normal non-crawling 9-month-olds in the availability phases of the study but did look to their mothers more quickly and vocalized less during the social referencing phase. The third study used a similar procedure and identical novel stimulus to examine 20, 11-month-old infants' social referencing behaviour in a laboratory situation. There was a significant difference between the infants who received a positive versus negative message for the contact with the car measures. When they received a negative message, infants tested in the laboratory were less likely to touch the stimulus car and touched it for a shorter time than infants of the same age and tested at home. Mothers of all infants participating in this study completed the Infant Characteristics Questionnaire. None of the infant characteristics predicted which infants would use the social referencing strategy. It is concluded that social referencing is not a strategy used extensively by 7-and 9-month old infants although social looking is common at these ages in response to new events. Locomotion experience has little effect on social referencing. Infants use information from a variety of sources to assess a new situation and 11-month-old infants are more likely to use social referencing as a strategy in an unfamiliar setting. Theoretical implications of the results are discussed in relation to the cognitive requirements of preverbal and emotional communication and the relative importance of social influences for interpreting novel events.

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