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Perceiving and interacting with our world is an amazingly complicated computational problem. Our brains need to infer the best cause of action from a long chain of ambiguous and noisy signals reflecting properties from the environment. To solve this problem, our brains make use of multiple pieces of information available in a given context. In these thesis, we explore the influence of context on decision-making. First, we focus on decisions made in the context were three options are available to be chosen. Second, we focus on decisions made in the context of variable prior information about the probability of occurrence of a given event. A particular emphasis is placed on distinguishing mechanisms that optimize the accuracy of decisions from those that comply with axiomatic prescriptions of rational behaviour. We show that even as simple an assumption as having Gaussian noise distorting the representation of value is enough to drive irrational behaviour, calling into question the validity of the axioms of rationality as a yardstick for measuring human behaviour. We also show that uncertainty arising at different stages of the long chain of information processing, can drastically impact the nature of the inference problem that humans have to solve in different contexts. We show two mechanisms present when humans construct their value preferences between three available options. These mechanisms prioritize what information gets further processed in a way that minimizes the effects of noise arising at later stages of processing. Finally, we provide a novel computational explanation for the mismatch typically observed between near-optimal perceptual choices and suboptimal cognitive judgments. Namely, that people are metacognitive blind to noise arising when integrating of multiple pieces of evidence. Together, we show that the brain tends to make excellent use of contextual information to guide it decisions. Perhaps so much so, that we often trust our judgments blindly.

Background: Postpartum depression is a serious, common, treatable condition, with broad repercussions in mother and family Ufe, but frequentiy under diagnosed. A screening tool, the Edinburgh Postnatal Depression Scale (EPDS) could improve the detection rate of depressive symptoms. Aim: To assess the efficacy of EPDS in the detection rates for depressive symptoms in the postpartum períod. To evalúate the feasibility of routine use of this screening scale in a Family Medicine Center. Material and methods: The medical records of women attended during 2002, were reviewed to detect the registry of depressive symptoms or request for psychiatric consultations for depression. During 2003, the EPDS was applied to a sample of 110 women. To confirm the postpartum depression diagnosed using the instrument, a structured psychiatric interview was administered to these women. Results: The medical records of 110 women aged 24±7years were reviewed and the instrument was applied to 110 women aged 26±7years. In the firstgroup, the spontaneous detection rate for depressive symptoms was 4.6% (5/110). In 26.4% of women in whom the instrument was applied, depressive symptoms were found and 15% had a postpartum depression. The application rate of the scale was 88% and the rate of acceptance by mothers was 100%. Conclusions: The EPDS improves signiñcanüy the detection rates of postpartum depressive symptoms, and it is well accepted by health professionals and mothers

Background: Postpartum depression is a serious, common, treatable condition, with broad repercussions in mother and family Ufe, but frequentiy under diagnosed. A screening tool, the Edinburgh Postnatal Depression Scale (EPDS) could improve the detection rate of depressive symptoms. Aim: To assess the efficacy of EPDS in the detection rates for depressive symptoms in the postpartum períod. To evalúate the feasibility of routine use of this screening scale in a Family Medicine Center. Material and methods: The medical records of women attended during 2002, were reviewed to detect the registry of depressive symptoms or request for psychiatric consultations for depression. During 2003, the EPDS was applied to a sample of 110 women. To confirm the postpartum depression diagnosed using the instrument, a structured psychiatric interview was administered to these women. Results: The medical records of 110 women aged 24±7years were reviewed and the instrument was applied to 110 women aged 26±7years. In the firstgroup, the spontaneous detection rate for depressive symptoms was 4.6% (5/110). In 26.4% of women in whom the instrument was applied, depressive symptoms were found and 15% had a postpartum depression. The application rate of the scale was 88% and the rate of acceptance by mothers was 100%. Conclusions: The EPDS improves signiñcanüy the detection rates of postpartum depressive symptoms, and it is well accepted by health professionals and mothers