The present paper deals with negativity and positivity effects in trait inferences and impression formation. In the first experiment we tested the suggestion of Skowronski and Carlston (1987) that in the domain of morality negative information is more diagnostic, will therefore receive more weight and result in a negativity effect whereas in the domain of abilities, positive information is more diagnostic resulting in positivity effects. Results of our first experiment support these predictions: negative behavioural information leads to more certain inferences concerning morality and positive behavioural information leads to more certain inferences concerning ability. In a second experiment, we investigated the relative weight of positive versus negative ability-and morality-related traits in an impression formation task. We counterposed traits from both morality and ability domains to see which was the most dominant in determining evaluative impressions. Findings of this second experiment showed strong negativity effects but also revealed that information related to morality is more influential in forming an evaluative impression than equally extreme information related to ability. Theoretical implications of these findings are discussed.