The role of cognitive effort in decision-making and reasoning errors. Reasoning errors: Beyond insufficient effort - implicating the Locus Coeruleus - Norepinephrine system

Cognitive effort is highly familiar in everyday life and may influence our decisions and task performance. However, researchers have struggled to both define and measure cognitive effort. A range of tools measuring cognitive effort has been developed within different lines of research. Yet it is unclear to what degree these tools are related and if they are measuring the same cognitive effort construct. Furthermore, the influential default-interventionist dual-process account proposes that a lack of cognitive effort is a significant source of errors in reasoning and decision-making. However, an accumulating body of research contradicts predictions from the default-interventionist account, giving rise to a new generation of dual-process models. Notably, a separate line of research applying single-process sequential sampling models proposes that bias in decision-making is exacerbated by more extensive integration of evidence. These separate lines of research make opposing predictions regarding pupil dilation. Pupil size can be used as an indicator of both cognitive effort and Locus Coeruleus – Norepinephrine activity. The default-interventionist account predicts that errors in reasoning should be associated with smaller pupil dilations, I.e. less cognitive effort. The extensive integration account proposes that larger pupil dilations, indicating low levels of norepinephrine and neural gain, leads to more extensive integration and more bias in reasoning. Thus, competing models and frameworks with opposing predictions regarding cognitive effort and errors in decision-making can be tested by measuring pupil size during performance on reasoning tasks. The aims of the thesis were to investigate the role of cognitive effort in decision-making and errors in reasoning. Further, to evaluate tools measuring cognitive effort in decision-making, and lastly to evaluate competing dual-process models and alternative frameworks of decision-making. Paper 1 assessed the shared variance between three behavioral measures of cognitive effort and their relationship to the need for cognition scale. Additionally, working memory capacity and subjective mental effort of the task paradigms was measured. The results showed no relation between the three behavioral measures of cognitive effort. However, two of the measures were related to need for cognition and working memory capacity. Contrary to dual-process model predictions, performance on a battery of rational reasoning tasks was ne