The "working emotion vocabulary" typically shows a preponderance of words for negative emotions (50%) over positive (30%) and neutral (20%) emotions. The theory of affect-as-information suggests that negative emotions signal problems or threat in the environment and are accompanied by detailed and systematic cognitive processing, while positive emotions signal a safe or benign environment and are accompanied by heuristic, schema-based cognitive processing. Further, the developmental theory of affect-complexity suggests that the ability to coordinate and manage complex emotions develops over the lifespan. More complex interpretation and reasoning about negative experience versus positive experience predicts that negative emotion labels will predominate in the emotion lexicon. The growth of affect-complexity over time predicts that the greater proportion of negative labels will remain constant for both young and older individuals. By asking monolingual Spanish-speakers in Mexico and monolingual English-speakers in the USA to make free-lists of as many emotions as they could in two minutes, we confirmed each of these predictions about the working emotion lexicon. Moreover, data from both languages showed the same proportional distribution, suggesting that the cognitive constraints on emotion processing and lexification may be cross-culturally invariant. (Contains 2 tables and 2 figures.)