This collection consists of data from several experiments investigating two topics. Two files contain data from experiments investigating the conjunction fallacy, particularly what combination rules participants are using to combine probabilities when estimating conjunctions and disjunctions. Three files contain data from experiments investigating the dilution effect, particularly whether the effect is really due to dilution of evidence or inference of missing evidence.The ways in which people combine information can show peculiar biases. For example, when combining two independent pieces of written evidence that point toward the same conclusion, people are often no more convinced than with a single pieces of evidence alone. However, this effect depends on the details of how the evidence is presented: if the same evidence is given in a perceptual task, then people are more convinced by the additional piece of evidence. This work will investigate the differences between cognitive and perceptual tasks of information integration, in order to develop a unified understanding of what drives people to combine information correctly or incorrectly. A variety of tasks will be explored using a common set of stimuli and manipulations in order to determine whether the change in combination rules are due to the cognitive or perceptual nature of the stimuli, more experience with the perceptual task, or participants having particular assumptions about how the information arises. In addition to evidence combination, these tasks will be used to explore how people combine risk and reward and how they combine probabilities.

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