The present research sought to describe and explain age related changes to associative learning processes. Eleven experiments were conducted using a human conditional learning paradigm. Background data on health, lifestyle, and cognitive ability were collected and used as predictor variables in multiple regression analyses. Experiments 1 to 8 were formative, and found that older participants showed an overall age related decline in learning ability exacerbated by the number of stimuli and outcomes used, and the concurrent presentation of different problem types. Configural models of learning (e.g. Pearce, 1994, 2002) best predicted young participants’ learning whereas older people’s learning was more consistent with elemental models (e.g. Rescorla-Wagner, 1972), suggesting an age related change in generalisation processes. Those who learned problems better were also more likely to be able to articulate a rule that had helped them learn the problem. Age itself was the most predominant predictor of accuracy in these experiments. Experiments 9, 10, and 11 were multiple stage experiments that looked at the extent of pro- and retro-active interference in learning. Experiments 9 and 10 used easy and hard HCL problems to examine the role of rule induction in learning. Older participants who had learned initial discriminations better were more prone to pro-active interference in both experiments, the extent of which was predicted most reliably by fluid intelligence. Rule learning had a profound effect on participants’ predictions during the unreinforced test stage. In Experiment 9 (Easy-Hard) younger participants suffered from more retroactive interference than older people. This pattern was far less pronounced in Experiment 10, (Hard-Easy) suggesting that problem order affected the way participants generalised from rule-based knowledge. This observation is inexplicable by associative learning theories, and explanation may require a problem solving approach. Experiment 11 examined feature-based generalisation. Again older participants suffered more proactive and retroactive interference and elemental theories predicted their responses best, whereas younger participants responses were consistent with configural models of learning. In this instance, resistance to pro- and retro-active interference was predicted by fluid intelligence. Overall the research concluded that there is a demonstrable, complexity dependent change in associative learning processes in later life. It appears that humans have an increasing tendency to rely on elemental, rather than configural processes of generalisation in later life, and this leads to overgeneralisation between stimuli and an inability to resist pro- and retroactive interference in learning. This may be as a result of an inhibitory or source monitoring failure as a consequence of atrophy in the frontal lobes of the brain, although some of the learning deficits are explicable through mnemonic decline.

Cette thèse avait pour principal objectif d’étudier la dissociation du système magnocellulaire et parvocellulaire en testant l’évolution de ces systèmes dans le vieillissement normal et la réhabilitation à l’aide de lunettes à filtre jaune. Pour cela deux paradigmes expérimentaux dont les caractéristiques des stimuli permettaient de biaiser le traitement visuel vers l’un ou l’autre des deux systèmes et dont les tâches impliquaient un niveau de traitement cognitif plus ou moins élaboré ont été utilisés. A l’aide d’une tâche de discrimination de luminance, les travaux ont mis en évidence l’apparition d’un déficit parvocellulaire massif dans le vieillissement ainsi qu’un déficit magnocellulaire de moindre ampleur au début du vieillissement mais qui s’accentuait rapidement au-delà de 75 ans. Dans une tâche de catégorisation d’objets, la présence du déficit magnocellulaire avec l’âge et le grand âge a été corroborée mais aucune répercussion du déficit parvocellulaire mis en évidence à un niveau de traitement plus précoce n’a été observée dans cette tâche. Concernant la réhabilitation, seul le groupe de participants très âgé (>75 ans) a vu ses performances améliorées par le filtre jaune dans la condition impliquant spécifiquement le système magnocellulaire à l’épreuve de discrimination de luminance. Dans l’épreuve de catégorisation, les deux groupes de participants âgés et très âgés ont montré une diminution significative de leur temps de réponse avec le filtre jaune accompagnée d’une amélioration de la précision de catégorisation pour le groupe très âgé, spécifiquement dans la condition mettant en jeu le système magnocellulaire.L’ensemble des résultats confirment donc la dissociation neuropsychologique entre système magnocellulaire et parvocellulaire : ils peuvent être sollicités de façon privilégiée chez l’adulte jeune en faisant varier à la fois plusieurs caractéristiques de la stimulation et la tâche ; ils ne vieillissent pas au même rythme et l’un d’entre eux peut être spécifiquement réhabilité / The thesis aimed at studying the dissociation between the magnocellular and the parvocellular system by testing their evolution in normal aging and their rehabilitation with yellow filter glasses. Two experimental paradigms whose specific stimuli characteristics and task allow to bias visual processing toward one or the other system and which involved a low or an elaborated cognitive processing were used.In a luminance discrimination task, the results showed a massive parvocellular and a lower magnocellular deficit at the beginning of aging, but the magnocellular deficit increased rapidly beyond 75 years old. In an object categorization task, the presence of magnocellular deficit with age and very old age was corroborated but there was no parvocellular deficit suggesting that the parvocellular deficit found at earlier stage of processing had no consequence for higher-level processes.Regarding rehabilitation, yellow filter improved sensitivity in the discrimination of luminance specifically in the condition involving the magnocellular system and for the very old group of participants (> 75 years old) only. In the categorization task, yellow filter significantly decreased response time specifically in the condition isolating the magnocellular system for both old groups and increased the accuracy for the very-old group.Taken together, the results confirm the dissociation between the magnocellular and parvocellular systems. Magnocellular system undergoes age-related changes at later stage of ageing than parvocellular system and it could be rehabilitated with yellow filter

No description available.

This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European-American adults. Nonlinear age-related changes were found for the coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change trajectories for sublimation and suppression showed that their use increased from adolescence to late middle age and early old age, and remained mostly stable into late old age. The change trajectory for intellectualization showed that the use of this defense mechanism increased from adolescence to middle age, remained stable until late midlife, and started to decline thereafter. The defense mechanisms of doubt, displacement, and regression showed decreases from adolescence until early old age, with increases occurring again after the age of 65. Linear age-related decreases were found for the coping mechanism of ego regression and the defense mechanisms of isolation and rationalization. Gender and socioeconomic status were associated with the mean levels of several coping and defense mechanisms, but did not moderate age-related changes. Increases in ego level were associated with increased use of the defense mechanism intellectualization and decreased use of the defense mechanisms of doubt and displacement. Overall, these findings in a European-American sample suggest that most individuals showed development in the direction of more adaptive and less maladaptive coping and defense strategies from adolescence until late middle age or early old age. However, in late old age this development was reversed, presenting potential challenges to the adaptive capacity of older adults.