Browsing by Subject "Psychology - General"

Now showing 1 - 11 of 11
  • Thumbnail Image
    Item
    Open Access
    A cross-linguistic study of certain temporal features of speech in stuttering and nonstuttering children
    (1986) Oosthuizen, Carol Louise; Du Preez, Peter
    Four experiments were performed to measure temporal coarticulatory speech features in the perceptually fluent speech of 120 South African children. The aim was to test, in a limited way, the postulate that stuttering may be essentially a disorder of speech timing. Comparisons were made between English- and Afrikaans-speakers, between younger (mean age 4.1 years) and older (mean age 6. 7 years) children, and between stutterers and nonstop utterers. Experiment one investigated voice onset time (VOT) of word-initial voiced and voiceless bilabial and apical stop plosives in isolated eve nonsense syllables. The VOTs were measured from oscilloscopic displays. Nonparametric statistical treatment identified certain trends in the data. English-speakers used short- and long-lag categories to express voiced and voiceless initial stops respectively. They showed a developmental trend in the direction of lengthening of VOT for voiceless stops. Afrikaans-speakers used two sets of short-lag VOT without aspiration to produce voiced and voiceless stops. Voicing lead occurred randomly as a stylistic variant. The stuttering children demonstrated longer VOTs than did nonstutterers. In addition, English-speaking stutterers failed to lengthen VOT for voiceless stops in the normal manner. This was attributed to difficulty with the physiological demands of long-lag VOT. Afrikaans speakers, who did not have to contend with the long-lag category, clearly distinguished between voiced and voiceless stops by means of VOT. Experiment two dealt with the categorical labelling of nonsense syllables employing the voicing contrast. In younger nonstuttering subjects, English-speakers performed better than did Afrikaans-speakers, owing to the greater number of perceptual cues available to them. All younger subjects needed a lot of training in order to label correctly, whereas older subjects needed little training. English stutterers performed slightly poorer than did nonstutterers, while even older Afrikaans stutterers performed very poorly. It was postulated that stutterers might be dependent on perceptual cues which become redundant for nonstuttering listeners. Afrikaans stutterers were additionally handicapped by the paucity of perceptual cues in their language. In experiments three and four, medial stop closure duration in vev nonsense syllables and medial vowel durations in eve nonsense syllables were measured. English and Afrikaans nonstutterers had longer stop closure durations on voiceless-than stops and in high vowel compared with low vowel environments. A devel6p:nental trend was identified in the direction of differential stop closure lengthening. Medial vowel durations were also lengthened in voiced and voiced sibilant consonant environments. Subjects showed increasing vowel differential durations with age. Stutterers showed the normal trends towards differential medial stop closure and vowel durations but appeared to have a developmental lag in this respect relative to nonstutterers. Since stutterers did not differ from nonstutterers on measures of whole syllable duration or medial VOT it did not appear as if they were simply moving their articulators slowly. Experiments three and four probably tapped neutrally programmed coarticulatory effects, whereas the VOT measure might reflect a lower aerodynamic-neuromuscular level of speech functioning, the voicing feature being primarily involved at both levels. The possibility exists and is strengthened by the results of the categorical labelling task, that a central timing disorder, manifest as a developmental lag, may have been operating in the stuttering subjects.
  • Thumbnail Image
    Item
    Open Access
    An investigation into parental perception of aspects of development and temperament in abused children
    (1980) Carlin, Leslie Stanley; Grovar, Vere M
    This investigation focussed on child-related and parent-related characteristics in the area of child abuse. Specifically. developmental and temperament factors were stressed in non- CNS impaired abused children. Suggestions in the literature have pointed to the possible importance of studying temperament factors in these children. especially in the light of features in the developmental and medical histories which may place them at increased risk for abuse. Levels of development in abused children have been explored in other studies. but their findings with respect to the non-CNS impaired sub-group have not yielded clarity on their developmental status. The perceptions of the children's temperaments and levels of development by the mother was also investigated in the light of theoretical models of child abuse which have claimed that abusing parents place unrealistic demands on their children. who are not capable of complying. The performance of ten abused children was compared with normal controls (matched for age and sex and from the same social class) on the Grover Developmental Charts. The same two groups of children were observed in a free-play situation during which time their behaviour was rated on six categories of temperament. and in three areas of development. viz. gross-motor functioning. receptive language and socialization skills. Temperament categories and scoring methods for both parents and children were adapted for use in this research from the work of Alexander Thomas and his co-workers. Results suggested that the abused children performed at significantly lower levels in the areas of gross-motor functioning and language. Their performance in the language area was characterised by a tendency to fail in items having a "social" component. No significant differences were found in the other areas of development studied (socialization skills and cognitive development). However, these results suggested a trend towards lower levels of functioning which was in keeping with the significant findings in the gross-motor and language areas. The temperament comparisons did not yield significant findings. Analysis of the data obtained from mothers suggested that they tended to rate their children's language development significantly lower than controls. we're not significant. The other perceptual comparisons the findings are considered in the light of relevant theoretical models in the area of child abuse. Implications of the findings for future research, the limitations of the methodology employed, and the usefulness of the findings for clinical practice are discussed.
  • Thumbnail Image
    Item
    Open Access
  • Thumbnail Image
    Item
    Open Access
    The hippocampus and its electrographic activity
    (1983) Hirschman, Glynne Hilton; Du Preez, Peter
    The thesis is divided into two parts. The first part presents a theoretical investigation of the functions of the hippocampus. Three theories are critically examined : (i) the Douglas ( 196 71 1972) and Kimble (1968) proposal that the hippocampus forms the neural substrate of Pavlovian internal inhibition (hereafter referred to as the inhibitory theory); (ii) the Olton, Becker & Handelmann (1979) suggestion that the hippocampus serves as a "working memory" register; and (iii) the O'Keefe & Nadel (1978) hypothesis that the hippocampus functions as a cognitive map. The adequacy of the three theories is tested against anatomical, physiological and behavioural evidence, and it is concluded that only the inhibitory theory is both internally consistent and able to accommodate the data. Furthermore, a detailed evaluation of criticisms of the theory (as presented primarily by Nadel, O'Keefe and Black 1975) reveals that many of the apparent anomalies in. the literature are, in fact, consistent with the theory, while others are based on unsound data. ,Further consideration of the anatomical and behavioural evidence suggests that the hippocampus gives rise to two separate circuits: a dorsal circuit, subserving the functions of internal inhibition, and a ventral circuit, mediating external inhibition. It is posited that the latter circuit produces its disinhibitory effect via the mammillothalamic tract.
  • Thumbnail Image
    Item
    Open Access
    Ingroup bias : the effect of status, legitimacy and cooperation on intergroup relations
    (1981) Finchilescu, Gillian; Du Preez, Peter
    Research on the effect of intergroup cooperation on intergroup relations has produced contradictory results. The functionalist proposition that cooperation leads to the reduction of intergroup discrimination has not been widely supported by empirical evidence. An emerging trend indicates that cooperation reduces bias only in circumstances where the distinction between ingroup and outgroup can be rendered less salient. The cognitive-motivational theory of intergroup relations (Tajfel and Turner, 1979) provides a framework through which intergroup bias and the salience of group distinctiveness may be understood as a function of the group's position on a status hierarchy and the perceived legitimacy of that status order. This study considered the effect of intergroup cooperation, compared with no cooperation and with intragroup cooperation, within this framework.
  • Thumbnail Image
    Item
    Open Access
    An investigation into the object grouping behaviour of young children from a low socio-economic background
    (1985) Biersteker, Linda; Davids, Fakhry
    Recent studies of object grouping in infants and preschool children by Sugarman (1983) suggest that they are capable of conceptualising inter-relationships between objects - a view which differs from accounts of classification by Inhelder and Piaget (1964) and Vygotsky (1962). These studies have concentrated on Western middle-class subjects. This study investigated the development of conceptual organisation seen in the grouping of sets of objects by young children, classified as "Coloured", from a low socio-economic background. A second focus of the study was on the effect of specific task variables on object grouping behaviour. Thirty-one low income subjects divided into four age groups - 16-24, 25-30, 31-36 and 37-42 months, were given six different free sorting tasks. Each involved the presentation of a scrambled array of eight objects to be divided into two classes. In one task the objects could be classified by bi-dimensional criteria, in the others by a single criterion. Subjects' spontaneous manipulations of the objects were measured in three ways - temporal grouping, spatial grouping and grouping procedure. Verbal references to class relations were also coded. For measures of temporal and spatial grouping, frequency of consistent one- and two-class groupings and inclusiveness of constructions were noted. Grouping procedure provided a measure of whether or not both classes were simultaneously considered. An additional two tasks designed to elicit simultaneous consideration of both classes were also administered to each subject. The data was analysed for differential age and task effects on grouping. The results indicate that performance on these tasks showed the same general developmental trends and task effects as those found in recent studies of middle-class children for both unidimensional and bidimensional groupings, thus confirming Sugarman's observations and suggesting a universal process of conceptual development. However, there was some evidence of a slower rate of development and levels of verbalisation were lower than those observed in studies of middle-class children. Subjects in this study could conceptually inter-relate objects shown both in their bidimensional groupings and in mixed order grouping procedure, but the latter was evident in elicited groupings and not in spontaneous play. These differences are discussed in relation to performance variables such as response set.
  • Thumbnail Image
    Item
    Open Access
    Manifest dream content, sex role orientation archetypes and the menstrual cycle : an experimental investigation
    (1984) Osborn, Claire Barbara; Faber, Phillip
    Previous research has found that dream content may vary as a function of the menstrual cycle. Parameters which have been found to fluctuate with the menstru.al cycle include sexual and aggressive content of dreams, dream unpleasantness, the frequency of dream recall and maternal and heterosexual dream content. This research also investigated the possibility that agency, communion and archetypality may fluctuate across the menstrual cycle. In addition to this the effect of sex-role orientation was investigated. There were consequently two groups of subjects, one with a masculine sex-role orientation and another with a feminine sex-role orientation. The subjects were 14 women aged between 21 and 28, who did not take a contraceptive pill, who had regular menstrual cycles, and who did not suffer from any severe form of psychopathology. Dream reports were obtained from both home diaries and REM awakenings. Basal body temperatures were recorded daily to enable the phase of the menstrual cycle to be accurately determined.
  • No Thumbnail Available
    Item
    Open Access
    Mental strategies and the perception of effort : implications for the psychological training of marathon runners
    (1985) Schomer, Helgo
    [missing pages 7-18] Several attempts have recently been made by psychologists to uncover the mystique that surrounds the superior athletes and their superior performance. Researchers wonder whether continuous participation in a specific sport induces both peak performance and certain mental strategies or whether the perchance or purposeful adoption of a cognitive strategy enhances performance (Cratty, 1983). In their effort to find a causal relationship, psychologists have endeavoured to understand the mental processes of athletes, speculating on how the quality or quantity of their thoughts might contribute to their excellent performance. Yet results have been clouded over by anecdotal reports and rather unsystematic accounts of subjective experiences and views. Tentative explorations into the mind of the marathoner are beginning to set the stage for the unravelling of this highly .complex and.fas~inating realm. This research project sets out to focus on the mental strategies of the marathoner and to discover their contribution to the marathoner's limit of performance.
  • Thumbnail Image
    Item
    Open Access
  • Thumbnail Image
    Item
    Open Access
    Relationship between prosocial moral reasoning, prosocial behavior, family functioning and social maturity in pre-primary school children
    (1985) Whiting, Gillian Mary; Du Preez, Peter
    The purpose of this correlation study was to attempt to account for differences in pre-schoolers moral reasoning about altruistic conflicts on the basis of healthier types of family functioning and greater degrees of· social maturity: to show whether these differences are reflected in an increase in prosocial behavior. Thirty-eight pre-school boys and girls responded to four simple moral stories about helping and sharing. (Moral R.). All responses of the children were coded by the researcher and an independent coder. Assessment of the extent of the children's own naturally occurring prosocial behavior was by the completion of a Likert-type rating scale (Pros. B.R.) by the teachers of the school. It was hypothesized that the use of more mature levels of moral reasoning would account for more prosocial behavior. Results confirmed the hypothesis. Family functioning was measured by the Family Assessment Device questionnaire (F.A.D.) and individually completed by all the mothers and fathers. The hypothesis that healthier family functioning patterns would reflect use of higher levels of moral reasoning was partially supported. The measurement of the extent of social maturity of each child was by means of a semi-structured interview with the mothers and utilizing the Vineland Social Maturity Scale (V.S.M.). It was hypothesized that healthier patterns of family functioning would foster greater social maturity. Results obtained did not support this hypothesis. Other hypotheses were; (a) that greater social maturity would account for the use of more mature levels of moral reasoning: this hypothesis was confirmed, (b) that greater social maturity would be related to increased prosocial behavior: results confirmed this hypothesis, (c) that increased prosocial behavior would be reflected by healthier patterns of family functioning: results did not support this hypothesis. As measurement was of an ordinal nature Spearman's non-parametric rank correlation was utilized. A subsidiary study was conducted in which the children's moral reasoning was examined by way of their dominant modal response. None of the pre-schoolers used the Kohlberg stage 1 authority and punishment as their modal response. Much hedonistic and needs-oriented reasoning was used. Spearman's rank correlation was used to examine relationships between the categories of moral reasoning. The use of hedonistic reasoning was negatively related to both needs orientation and stereotypic reasoning. Other relationships did not reach statistical significance.
  • Thumbnail Image
    Item
    Open Access
    The relationship between RFT performance and inter- and intra-modal matching tasks
    (1979) Isaacs, Sedick; Du Preez, Peter
    This study attempted to relate a field dependence measure viz. rod and frame test performance to scores on inter-and intra.- modal matching tasks. The view taken is that since in the rod and frame test situation two sets of sensory data, viz. vision and kinaesthesia seem significant for good performance, rod and frame test ability must somehow be related to the efficiency with which the two sets of data are processed. The study was based on the observation of Vaugh and Ellinger (1966) that the field independent subject is better at a form discrimination task than the field dependent. Form discrimination is in fact a type of cross modal matching task between the kinaesthetic modality and vision. In the present study lines and widths of solid objects instead of forms were used in order to facilitate measurement. An attempt was also made to construct a rod and frame test that is performed only in the kinaesthetic modality in order to determine whether the rod and frame test must of necessity be cross modal in nature and whether this kinaesthetic rod and frame test is related to the efficiency of intramodal matching in the kinaesthetic modality. Forty-six male subjects were used in the non-visual rod and frame test study and sixty-six male subjects were used in the study to determine whether rod and frame test performance is related cross modal matching ability. A portable version of the rod and frame test as described by Morris ( 1967) was used. correlation was found between the rod and frame test and the non-visual rod and frame test (called the somaesthetic rod and frame test). The implication of the results for the differential hypothesis at briefly discussed a moderate correlation.