No description available.

The focus of the thesis is the investigation of the causal nature of the established association between rumination and that ability to resolve interference from task-irrelevant information, and prepotent responses. Rumination is a term used to refer to both unhelpful dwelling on negative moods and depressive symptoms (e.g., Nolen-Hoeksema, 1991), and repetitive intrusive thoughts around the theme of unresolved personal goals (Martin & Tesser, 1996). It has been proposed that rumination occupies working memory resources, thereby depleting cognitive control capabilities necessary for the performance of concurrent effortful tasks (Hartlage, Alloy, Vasquez, & Dykman, 1993; Hertel, 2004; Watkins & Brown, 2002). This model constitutes one possible account of the considerable data demonstrating an association between depressive rumination and deficits on tasks invoking inhibitory processes (Joormann, Yoon, & Gotlib, 2007). An inhibition construct is invoked to account for the empirical observation of interference; however there are few instances where inhibition is unambiguously driving interference (MacLeod, 2007). Moreover, there is evidence that inhibition is not a unitary construct (Friedman & Miyake, 2004). Five experiments manipulated rumination on depressive symptoms and on personal goals in dysphoric and unselected samples in order to test Watkins and Brown’s (2002) hypothesis that state rumination impairs interference control capabilities. The causal impact of state rumination was examined on interference control tasks that implicate different inhibitory sub-types: resistance to proactive interference from positive and negative material (Studies One, Two, and Five), and prepotent response inhibition on a go/no-go paradigm (Studies Three and Four). No evidence was found to support the prediction that state rumination about depressed mood (Studies One and Two) or on-going personal goal discrepancies (Study Five) causes difficulties resolving interference from irrelevant emotional material relative to non-ruminative control conditions in both dysphoric (Studies One and Two) and unselected (Study Five) samples. No evidence was found to support the prediction that state rumination about personal goal discrepancies impairs prepotent response inhibition relative to non-ruminative control conditions (Studies Three and Four). There was some tentative evidence to suggest that ruminating on personal goal discrepancies increased efficiency in holding a single goal active in working memory without reinforcement (Study Four). The implications of these findings for existing models of the causal nature of the relationship between rumination and interference control processes is discussed (Chapter Nine). It is concluded that models proposing a causal impact of state rumination on available working memory capacity are insufficient to fully account for the established association between the trait tendency to ruminate and increased susceptibility to interference from irrelevant material.

One hypothesis regarding the etiology of Attention-Deficit/Hyperactivity Disorder (ADHD), is to conceptualize the disorder as an "inhibition" disorder. Furthermore, it has been suggested that inhibition is not a single all-encompassing construct, but rather a series of closely related processes. There has been limited examination as to whether children with ADHD are impaired on measures of cognitive inhibition (also known as proactive and retroactive interference). This project examined children with ADHD's susceptibility to proactive and retroactive interference in both verbal and visual-spatial modalities in comparison to typically developing children utilizing a novel coding system of the Children's Memory Scale (CMS). It was found that children with ADHD exhibited greater levels of visual-spatial retroactive interference than their typically developing peers. Additionally, children with ADHD did not differ from controls on any measure of verbal interference. Implications for clinical practice and future directions for research are discussed.

No description available.

Arbeitsgedächtnisdefizite lernbehinderter Kinder sind bisher vor allem im phonologischen Bereich nachgewiesen worden. Die eigene Studie untersucht mögliche Defizite im Bereich der zentralen Exekutive mit zwei Schwerpunkten: (a) Lassen sich bei der Steuerung selektiver Aufmerksamkeit spezifische Defizite Lernbehinderter identifizieren? (b) Zeigen sich Besonderheiten in den Alterszugewinnen selektiver Aufmerksamkeit? In der Untersuchung wurden Grundschulkinder gleichen mentalen und gleichen chronologischen Alters mit einer Gruppe lernbehinderter Kinder einer vierten Klasse verglichen. Zusätzlich wurden ältere Schulkinder (7. Klasse, 4. Klasse, 7. Klasse einer Sonderschule L) einbezogen, so dass auch prüfbar wird, inwiefern sich Alterszugewinne der kognitiven Funktionen bei lernbehinderten im Vergleich zu unauffälligen Schülern unterscheiden. Einbezogen wurden nur L-Schüler mit einem IQ < 85. Zur Erfassung der zentral-exekutiven selektiven Aufmerksamkeit wurden drei verschiedene Aufgabenanforderungen (TAP, Stopp-Signal, TEZEK) gewählt. Die Befunde deuten auf ein frühes Funktionsdefizit der lernbehinderten Kinder hin, das bis 14 Jahre weitgehend kompensiert werden kann.

No description available.

No description available.