Fluency and positivity as possible causes of the truth effect.

Statements' rated truth increases when people encounter them repeatedly. Processing fluency is a central variable to explain this truth effect. However, people experience processing fluency positively, and these positive experiences might cause the truth effect.

Why positive information is processed faster: the density hypothesis.

The authors postulate and show a speed advantage in the processing of positive information and hypothesize that this advantage is caused by the higher density of positive information in memory: Positive information is more similar to other positive information, in comparison with the similarity of negative information to other negative information. This "density" hypothesis is supported by multidimensional scaling of evaluative stimuli and response latency experiments. The relevance and explanatory power of the hypothesis is demonstrated by secondary data analyses of prior research in the evaluative priming paradigm.