The dissertation explores the effect of the knowledge base on the acquisition of memory strategies. It is postulated that 'salient' categories - highly elaborated categorial structures in the knowledge base - facilitate memory performance so that elevated levels of clustering and recall, and an emergent organisational strategy, can be expected in young children's memory performance with such categories. Two multitrial, free-recall experiments were conducted to test the hypothesis. The first experiment analysed the memory performance of preschool children and adults on category type (salient versus nonsalient categories). The second experiment analysed the effect of category saliency on memory search processes. The experiments yielded evidence suggesting that highly salient items in the knowledge base are easily activated during the course of memory retrieval, resulting in enhanced levels of recall with such items, and the early manifestation of an organisational strategy. / Psychology / M.A. (Psychology)

Thesis (M.A.)--University of South Africa, 1992.

This thesis evaluated the extent to which long-term memory linguistic representations (syntactic, semantic, prosodic and lexical) affect immediate verbal repetition performance. The effects of these linguistic factors on short-term memory span were explored through an experiment with 140 English- and Czech-speaking participants. The experiment employed nine experimental conditions which varied the presence/well-formedness of linguistic information in four domains: the lexicon, morphosyntax, semantics, and suprasegmental phonology. This resulted in a spectrum of stimuli with semantically, syntactically and prosodically well-formed sentences with real lexical items at one end, through to a list of nonwords with lexical, semantic, prosodic and syntactic information removed. One hundred typically developing children (50 Czech- speaking; 50 English-speaking) aged 4-5 years and 40 adults (20 Czech-speaking; 20 English-speaking) participated in the study. In each condition, participants were asked to repeat blocks of successively longer stimuli to establish their maximum spans. The results were similar between age groups and across languages. Each linguistic factor had a significant effect on short-term memory span. The presence of nonwords and syntactic violations dramatically reduced memory span, while semantic implausibility and the removal of sentence prosody played a smaller yet significant role. Despite the typological differences between Czech and English, the same robust differences between conditions were found in both languages. The results provide further evidence that immediate verbal repetition is highly sensitive to the linguistic structures present in the stimuli. It is argued that theories which aim to account for data from immediate repetition should not be limited to lexical phonology but also need to address how syntactic, prosodic, semantic and lexical representations contribute to repetition performance. The findings of this thesis support the theoretical framework of verbal short-term memory emerging from a temporary activation of long-term memory representations and reinforce the view that language and memory are inextricable.

The current research aimed to answer two main research questions. First, do variations in report-criterion option have differential effects on observing what is indeed remembered? Second, does increasing the inter-relatedness between target items have the same facilitative effect on metamemory just like it does on retrieval, or does it deteriorate in the same way as metacognitive monitoring measured by type-2 signal detection theory (dissociation)? Contrary to some earlier findings, Experiments 1 and 2 showed that participants do indeed withhold some correct responses due to the stringent report criterion. As a result, they report more correct responses when report option is maximally liberal (e.g., forced report) compared to a stringent report-criterion (freereport) particularly in uncued recall (Experiment 2). Experiment 3 found that when participants are encouraged to study cue-target pairs by focusing on targets more, intertarget association (ITA) is utilised to retrieve target items at retrieval. Thus, whilst retrieval of targets is facilitated, monitoring of the responses is not. Experiment 4 clearly showed a dissociation between memory and metacognitive monitoring due to high-ITA. Experiment 5, then, confirmed that the dissociation emerges due to the utilization of ITA by showing that it is attenuated in cued recall via ‘individuating’ the pairs (e.g., by interactive imagery). Confirming that the semantic context in which the target items studied is the critical factor to yield the observed dissociation, Experiment 6 showed that it is a strategic process that leads to the dissociation rather than solely an automatic process that facilitates retrieval of related targets by semantic activation. The results of the experiments were in line with the expectations of generate-recognize models (e.g., Bahrick, 1970) and showed that type-2 signal detection theory, which is based on this model, is an effective tool to investigate both memory and metamemory performance. The results were discussed with regards to the related literature.

Flexible and goal-driven behaviour requires a process by which the appropriate task-set is selected and maintained in a privileged state of activation. This process can be conceptualised as loading a task-set into a procedural working memory (PWM) buffer. Task switching experiments, which exercise this process, reveal “switch costs”: increased reaction times and error rates when the task changes, compared to when it repeats. The process of loading a task-set into PWM may be one source of these costs. The switch cost is reduced with preparation, suggesting that at least some of the processes involved in a successful change of task can be achieved in advance of the stimulus. The aim of this thesis was to investigate the properties of PWM, and its contribution to task-set control. One account of PWM distinguishes between the level at which recently exercised (but currently irrelevant) task-sets are represented, and the level at which only the currently relevant task-set is maintained in a most active state. To distinguish between these levels of representation, and to assess the extent to which the process of getting a task-set into a most-active state (loading it into the PWM buffer) is subject to a capacity limit at each level, the experiments varied the number of tasks participants switched among (Experiments 1 and 2), and the complexity of individual task-sets (Experiments 3-6) in a task-cueing paradigm. In Experiments 1 and 2, participants switched among three or five tasks, in separate sessions. There was no effect of the number of tasks on the switch cost, or its reduction with preparation, provided that recency and frequency of task usage were matched. When recency and frequency were not matched, there appeared to be a larger switch cost with five tasks at a short preparation interval, suggesting that the time consumed by getting a task-set into a most active state is influenced by its recency and frequency of usage, not the number of alternatives per se. However, Experiment 3 showed that the time required to select an S-R mapping within a task-set does increase as a function of the number of alternatives (even when stimulus frequency and recency are matched), suggesting that representation of the most active task-set in a PWM buffer is subject to a strict capacity limit. Experiments 4-6 further investigated the capacity limit of this PWM buffer, and found that task-set preparation was more effective for task-sets that are less complex (i.e. specified by fewer S-R rules). These findings suggest that only very few S-R rules can be maintained in a most active state in the PWM buffer. Finally, Experiments 7-9 investigated whether S-R rules are represented phonologically for task-set maintenance and preparation, by manipulating the phonological properties of the stimulus terms. But task-cueing performance was not affected by the name length (Experiment 7) or phonological similarity (Experiments 8 and 9) of the stimulus terms. These results suggest that phonological representations of S-R rules do not make a functional contribution to task-set control, possibly because the rules are compiled into a non-linguistic PWM. The results of these experiments are discussed in terms of a procedural working memory which is separate from declarative working memory, and distinguishes between two levels of task-set control: the level of task-sets, which are maintained in a capacity unlimited state of representation, and the level at which the currently relevant task-set is maintained in a most-active but highly capacity limited state of representation.

There is a large range of models of working memory, each with different scopes and emphases. Current interest focuses strongly on the interaction of working memory with long-term memory, as it has become clear that models of working memory alone are incapable of capturing some of our complex cognitive abilities. Most models have contrasting views on how this interaction is implemented. In this thesis, three classes of models are defined, each proposing a different type of interaction. The first model proposes that working memory acts as a gateway for perceptual input on its way to long-term memory. In the unitary model, working memory is seen as comprising the activated portion of long-term memory. The workspace model views working memory as a workspace that is separate from, and deals with the activated contents of long-term memory. The main aim of this thesis was to address the differences between these three models experimentally. Experiments 1 – 7 employed a dual-task paradigm to investigate the effects of irrelevant visual input on visuo-spatial working memory tasks. Two main findings emerged: (1) maintenance of images in working memory was largely insensitive to the effects of concurrent perceptual input; (2) mental imagery was susceptible to interference from irrelevant visual input. This interference effect was selective, as demonstrated by a lack of disruption of imagery by other secondary tasks. Experiment 8 further tested the three models by investigating implicit processing of visual information by neglect patients. It was found that implicit processing is mediated by the activation of long-term memory, in the absence of a conscious representation in working memory. These results together converge to support the workspace model, and suggest a view in which perceptual input activates the contents of long-term memory, prior to these activated representations being made available in a functionally separate working memory system for further processing. The gateway model and unitary model are unable to accommodate all findings. The implications of these results for existing theories about working memory are discussed.

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The biological energy concepts used by Freud to account for unconscious mental processes in psychoanalysis are discredited by modem biological findings. As a result, different psychoanalytic schools developed new foundational theories in order to verify unconscious mentation. The present study argues that these theories are unsuccessful for two main reasons. Firstly, replacing Freud's drive energy theory with other equally hypothetical foundational constructs does not solve the problem of finding proof for the existence of unconscious mentation. Secondly, the clinical psychoanalytic definition of unconscious mentation as imaginary, internally generated processes, autonomous from the external world is misguided. External sensory data may play a formative role in producing unconscious mentation. In particular, neurobiological findings on sensory data encoding and storage in human infants may throw light on the nature of unconscious processes. The present study therefore compares ideas derived from Lacanian psychoanalysis with neuropsychological memory and infant research findings to ascertain whether unconscious mentation is linked to the memory encoding of sensory data in infants. This analysis is in tum contrasted with a more contemporary psychoanalytic synthesis of findings on infant memory and unconscious mentation (Lichtenberg, 1989, Lichtenberg, Lachmann, and Fosshage, 1992). The latter theory identifies connections between unconscious mentation and the encoding of sensory memories in infancy, but does not connect the episodic and procedural memory constructs used in this account to specific neurolo·gical mechanisms in the brain. The present study's original contributions therefore involve firstly connecting the development of aversive episodic and procedural memories to neurological mechanisms in the brain during the period between birth and 28 months of age. Secondly, this memory model suggests that the storage of aversive memories in infancy has lasting unconscious motivational significance for subjects. Presymbolic memories may unconsciously manipulate conscious attention and memory retrieval in verbal subjects, inviting comparison with the psychoanalytic concept of dynamic unconscious mentation. Thirdly, the presymbolic memory model contributes towards a novel understanding of false memories of childhood sex abuse, and the dissociation of real traumatic memories that occur in many cases of Post Traumatic Stress Disorder. / Psychology / D.Litt. et Phil. (Psychology)

The biological energy concepts used by Freud to account for unconscious mental processes in psychoanalysis are discredited by modem biological findings. As a result, different psychoanalytic schools developed new foundational theories in order to verify unconscious mentation. The present study argues that these theories are unsuccessful for two main reasons. Firstly, replacing Freud's drive energy theory with other equally hypothetical foundational constructs does not solve the problem of finding proof for the existence of unconscious mentation. Secondly, the clinical psychoanalytic definition of unconscious mentation as imaginary, internally generated processes, autonomous from the external world is misguided. External sensory data may play a formative role in producing unconscious mentation. In particular, neurobiological findings on sensory data encoding and storage in human infants may throw light on the nature of unconscious processes. The present study therefore compares ideas derived from Lacanian psychoanalysis with neuropsychological memory and infant research findings to ascertain whether unconscious mentation is linked to the memory encoding of sensory data in infants. This analysis is in tum contrasted with a more contemporary psychoanalytic synthesis of findings on infant memory and unconscious mentation (Lichtenberg, 1989, Lichtenberg, Lachmann, and Fosshage, 1992). The latter theory identifies connections between unconscious mentation and the encoding of sensory memories in infancy, but does not connect the episodic and procedural memory constructs used in this account to specific neurolo·gical mechanisms in the brain. The present study's original contributions therefore involve firstly connecting the development of aversive episodic and procedural memories to neurological mechanisms in the brain during the period between birth and 28 months of age. Secondly, this memory model suggests that the storage of aversive memories in infancy has lasting unconscious motivational significance for subjects. Presymbolic memories may unconsciously manipulate conscious attention and memory retrieval in verbal subjects, inviting comparison with the psychoanalytic concept of dynamic unconscious mentation. Thirdly, the presymbolic memory model contributes towards a novel understanding of false memories of childhood sex abuse, and the dissociation of real traumatic memories that occur in many cases of Post Traumatic Stress Disorder. / Psychology / D.Litt. et Phil. (Psychology)

La mémoire épisodique est la fonction neurocognitive humaine permettant de se souvenir des événements passés situés dans leur contexte spatio-temporel ainsi que de se rappeler d'exécuter des actions futures spécifiques et d'imaginer des événements futurs variés. Comme d'autres capacités complexes, son développement est lié à d'autres fonctions telles que les fonctions exécutives et la théorie de l'esprit. Elle peut être évaluée avec du matériel de laboratoire nécessitant une mémorisation de nouvelles informations et d'actions futures à réaliser plus tard (mémoires rétrospective et prospective, respectivement), ainsi que via des événements personnels (rappel du passé et imagination du futur ou mémoire autobiographique passée et future, respectivement). L'objectif de cette thèse était, d'une part, de comparer les aspects passé et futur de la mémoire épisodique dans une approche développementale de l'enfant d'âge scolaire au jeune adulte, tout en explorant les mécanismes sous-jacents. D'autre part, le but était également de comparer des tâches autobiographiques et des tâches de laboratoire plus écologiques en réalité virtuelle.Les résultats suggèrent un développement plus progressif de l'aspect futur de la mémoire épisodique (plus de différences chez les enfants), tandis que l'aspect passé semble être bien développé à l'adolescence. Concernant les mécanismes, les performances aux tâches autobiographique et en réalité virtuelle (corrélées entre elles) sont liées aux fonctions exécutives et aux capacités narratives ; de plus, les capacités de rappel lors du test de réalité virtuelle dépendent des fonctions exécutives, la mémoire autobiographique passée et future et la théorie de l'esprit (seulement pour le futur), tandis que les capacités de mémoire autobiographique dépendent de la mémoire du futur en réalité virtuelle en plus des fonctions exécutives et de l'âge.Ces données démontrent que malgré un développement plus progressif de l'aspect futur que passé de la mémoire épisodique, le fonctionnement mnésique dans des environnements virtuels est comparable à la mémoire au quotidien, compte tenu de leurs inter-corrélations et de leurs mécanismes au moins en partie communs. Par ailleurs, les tâches de réalité virtuelle peuvent trouver toute leur utilité dans l'évaluation des patients pédiatriques neurologiques dont les déficits mnésiques peuvent être plus ou moins subtils et se refléter plus aux contextes quotidiens qu'aux contextes des évaluations de type papier-crayon. / Episodic memory is the uniquely human neurocognitive function that enables us to recall past events situated in their spatio-temporal context and to remember to carry out specific future actions as well as imagine various personal future events. As all complex abilities, its functioning is linked to other cognitive capacities such as executive functions and theory of mind. It can be assessed with laboratory-based materials requiring the memorization of information and future actions to be recalled later (retrospective and prospective memory, respectively) and via personal events (recalling past ones and imagining future ones or past and future autobiographical memory, respectively). The aim of this thesis was, on the one hand, to compare both past and future aspects of episodic memory functioning in a wide developmental age span (from young schoolchildren to young adults), and to explore underlying developmental mechanisms. On the other hand, we also aimed to compare personal events¿ (autobiographical) tasks with more ecological laboratory tasks using virtual reality. Results suggest a more progressive development of the future aspect of episodic memory (more differences between children), whereas both retrospective and past autobiographical memory seem to be quite functional by adolescence. Regarding mechanisms, both autobiographical and virtual reality performance, in addition to correlating with each other, are linked to executive functions and narrative abilities; also, memory abilities assessed via virtual reality depend on executive functions, past and future autobiographical memory and (only future memory) on theory of mind performance, whereas autobiographical memory abilities depend on virtual reality-based future memory in addition to executive functions and age. Our data demonstrate that despite a more progressive development of the future aspect of episodic memory than of its past aspect, memory functioning in virtual environments is indeed comparable to daily life memory, as these abilities are strongly inter-linked and have at least partly common mechanisms. Also, virtual reality tasks can be used for memory assessments in pediatric neurological patients whose potential memory deficits can be more or less subtle and thus more detectable in daily life contexts as opposed to paper-and-pencil types of contexts.