This thesis aims to explore the role of executive functions in multitasking. Research has shown that severe performance decrements often arise in dual-task performance, also called multitasking, as compared to single task performance. This reflects a limitation in processing temporally overlapping information. Interference between tasks arises due to a bottleneck process limited to processing only one task at a time. It has been proposed that this interference is resolved by executive functions. However, the dual-task paradigm employed in this thesis, Psychological Refractory Period (PRP) paradigm, (Pashler, 1994) is typically investigated in the field of human action performance, and the exact concept of executive functions remains underspecified. However, while underspecified in the area of action performance, executive functions have been investigated in detail in the field of memory research, more specifically in the context of working memory (WM). Therefore, the aim of this thesis was to investigate whether the executive functions in PRP are related to the executive functions as discussed in the context of WM. To test this question, we combined the PRP paradigm with a WM task, creating a complex WM span task. If the executive functions of WM and PRP are indeed related, then an interaction between the two tasks should be evident. Participants were presented with a sequence of letters to remember, followed by a processing block in which they had to perform either a single task or a dual-task, and finally were asked to recall the letters. Results (Chapter 2) showed that recall performance decreased when performing a dual-task as compared to performing a single task. This supports the assumption that PRP dual-tasks demand executive functions of WM. Following this, two other experiments were performed each with a different parametric modulation of the processing demands of the PRP dual task; response order (fixed vs random; Chapter 3) and stimulus onset asynchrony (SOA, short vs long; Chapter 4) of the component tasks. Recall performance was lower after a more difficult dual-task compared to an easier dual-task, which again indicates that demands on executive functions are increased in the dual-task. While previous neuroscientific research indeed showed that dual-tasks as well as WM tasks rely on lateral-prefrontal cortices (LPFC), it remains unknown whether both tasks activate the same areas or different sub-areas of the LPFC. Therefore, this study (Chapter 6) investigated how the neuroanatomical correlates of both dual-task and WM compare to each other. The brain activation for the PRP and WM tasks showed considerable overlap as well as some differentiation. Both tasks activated, among other areas, the inferior frontal junction. With respect to differences, the PRP task activated more the inferior middle frontal gyrus (MFG) whilst the WM component activated more the superior MFG. Thus, results support the assumption that PRP dual-tasks demand the executive functions of WM. This will allow us to inform theoretical models of cognition and to get a better understanding of human cognition. Future studies can build on this in order to create a more consolidated conceptualisation of the relationship between WM and multitasking.

This dissertation studies firms' strategic interactions in anticipation of random service disruption following technology failure. In particular it is aimed at understanding how contracting decisions between a vendor and one or multiple clients affect the firms' subsequent decisions to ensure disruption response and recovery are managed as efficiently as possible. This dissertation consists of three studies that were written as standalone papers seeking to contribute to the literature on contract design and technology management in operations management. Together, the three studies justify the importance of structuring the right incentives to mitigate disruption risks. In the first study we contribute to this literature by means of an analytical model which we use to examine how a client and vendor should balance investments in response capacity when both parties' efforts are critical in resolving disruption and each may have different risk preferences. We study the difference in the client's optimal expected utility between a case in which investment in response capacity is observable and a case in which it is not and refer to the difference in outcomes between the two cases as the cost of complexity. Firstly, we show that the cost of complexity to the client is decreasing in the risk aversion of vendor but increasing in her own risk aversion. Secondly, we find that a larger difference in risk aversion between a client and vendor leads to underinvestment in system uptime in case the client's investment is observable, yet the opposite happens when the client’s investment is not observable. In the second study we further examine the context of the first study through a controlled experiment. We examine how differences in risk aversion and access to information on a contracting partner’s risk preferences interact in affecting contracting and investment decisions between the client and vendor. Comparing subject decisions with the conditionally optimal benchmarks we arrive at two observations that highlight possible heuristic decision biases. Firstly, subjects tend to set and hold on to an inefficiently high investment level even though it is theoretically optimal to adjust decisions under changing differences in risk preferences. Secondly, subjects tend to set and hold on to a penalty that is too high when interacting with more risk averse vendors and too low in case the vendor is equally risk averse. Furthermore, cognitive feedback on the vendor’s risk aversion appears to have counterproductive effects on subject’s performance in the experiment, suggesting cognitive overload can have a reinforcing effect on the heuristic decision biases observed. In the third study we construct a new analytical model to examine the effect of contract design on a provider's response capacity allocation in a setting where multiple clients may be disrupted and available response capacity is limited. The results show that while clients may be incentivized to identify and report network disruptions, competition for scarce emergency resources and the required investment in understanding their own exposure may incentivize clients to deliberately miscommunicate with the vendor.

No description available.

Cognitive flexibility is an important mechanism enabling organisms to adapt to their changing environment. Different brain structures are involved in this complex process. It has been repeatedly shown that the striatum is one of the key structures controlling cognitive flexibility. Striatum receives rich input from different brain regions while its output is rather uniform. Striatal functions and signalling are greatly modulated by dopamine and acetylcholine. A number of studies have shown involvement of striatal acetylcholine and its receptors in the control of cognitive flexibility but very little is known about the role of M4 muscarinic acetylcholine receptors. These receptors are inhibitory, and they have been shown to induce long-term depression in striatal medium spiny neurons, therefore opposing the action of the dopamine D1 receptors. We hypothesize that the inhibitory effect of M4 muscarinic acetylcholine receptors may supress spiny projection neurons coding for outdated and no longer effective behavioural strategy and thus they may be necessary for the flexible change of behaviour. In the present thesis, I investigated the effects of pharmacological antagonism of M4 receptors on cognitive flexibility of mice tested in a simple reversal learning paradigm. Key words: striatum; cholinergic...

<p>Sömnsvårigheter hos ungdomar är ett växande problem i Sverige men det saknas forskning om behandlingsmetoder för åldersgruppen. Syftet med studien var att testa kognitiv terapi med beteendeexperiment (KT-I) på gymnasieungdomar med primär insomni. Studien genomfördes enligt en Single Subject design med för- och eftermätning. Tre ungdomar i åldern 16-18 genomgick en sju veckor lång behandling efter 1-2 veckors baslinjemätning. Resultatet visade att svårighetsgrad av insomni minskade, att funktionsförmågan dagtid förbättrades och behandlingsmålen uppfylldes i hög grad. Dagliga mätningar visade att förändring av sömnrelaterade symtom och dagtidssymtom varierade mellan deltagarna. Graden av vidmakthållande kognitiva processvariabler minskade. Slutsatser som kan dras är att KT-I är en lovande behandlingsmetod för ungdomar med insomni och att metoden bör testas ytterligare i randomiserade kontrollerade studier.</p> / <p>Sleeping difficulties are an increasing problem in Sweden for youths today, but there is a lack of research on treatments for this age group. The aim of the study was to investigate the effects from Cognitive Therapy with Behavioural Experiments (CT-I) on youths with primary insomnia in upper secondary school. The study was conducted according to a Single-Subject design with pre- and posttests. Three youths between the ages of 16-18 participated in a seven week long treatment, after 1-2 weeks of baseline measures. The results showed that the degree of insomnia decreased, that the ability to function during daytime increased, and that the treatment goals were met to a large extent. Daily measures showed that changes in sleep related symptoms and daytime symptoms varied among the participants. The degree of maintaining cognitive processes decreased. The conclusions that can be drawn are that CT-I is a promising treatment for youths with insomnia and that the method should be tested further in randomized controlled studies.</p>

Sömnsvårigheter hos ungdomar är ett växande problem i Sverige men det saknas forskning om behandlingsmetoder för åldersgruppen. Syftet med studien var att testa kognitiv terapi med beteendeexperiment (KT-I) på gymnasieungdomar med primär insomni. Studien genomfördes enligt en Single Subject design med för- och eftermätning. Tre ungdomar i åldern 16-18 genomgick en sju veckor lång behandling efter 1-2 veckors baslinjemätning. Resultatet visade att svårighetsgrad av insomni minskade, att funktionsförmågan dagtid förbättrades och behandlingsmålen uppfylldes i hög grad. Dagliga mätningar visade att förändring av sömnrelaterade symtom och dagtidssymtom varierade mellan deltagarna. Graden av vidmakthållande kognitiva processvariabler minskade. Slutsatser som kan dras är att KT-I är en lovande behandlingsmetod för ungdomar med insomni och att metoden bör testas ytterligare i randomiserade kontrollerade studier. / Sleeping difficulties are an increasing problem in Sweden for youths today, but there is a lack of research on treatments for this age group. The aim of the study was to investigate the effects from Cognitive Therapy with Behavioural Experiments (CT-I) on youths with primary insomnia in upper secondary school. The study was conducted according to a Single-Subject design with pre- and posttests. Three youths between the ages of 16-18 participated in a seven week long treatment, after 1-2 weeks of baseline measures. The results showed that the degree of insomnia decreased, that the ability to function during daytime increased, and that the treatment goals were met to a large extent. Daily measures showed that changes in sleep related symptoms and daytime symptoms varied among the participants. The degree of maintaining cognitive processes decreased. The conclusions that can be drawn are that CT-I is a promising treatment for youths with insomnia and that the method should be tested further in randomized controlled studies.