The aim of our experiment was to analyse the effect of the emotional valence (positive, negative, or neutral) on true and false recognition, matching the arousal, frequency, concreteness, and associative strength of the study and recognition words. Fifty younger adults and 46 healthy older adults performed three study tasks (with words of different valence: positive, negative, neutral) and their corresponding recognition tests. Two weeks later, they performed the three recognition tests again. The results show that words with a negative valence (...) produced less true recognition and less false recognition than words with a positive or neutral valence, in both younger and older adults, on the immediate recognition test. This pattern of results was also found in the younger adults on the delayed recognition test, whereas in the older participants, these differences disappeared. Thus, when arousal is controlled, both younger and older adults tend to recognise negative information worse than positive or neutral information, but they also commit fewer errors. Results would suggest that the greater arousal commonly associated with negative stimuli, rather than their own valence, could explain some of the contradictory results found in the literature. (shrink)