information:highlighting, structural:expansion
Nonstandard spoilers

Behavioral economists have shown individual irrationality involves violations of IIA (e.g. with decoy effects), suggesting human behavior might cause IIA failures even if the voting method itself does not. However, past research on similar effects has found their effects are typically small, and such psychological spoiler effects can occur regardless of the electoral system in use. Balinski and Laraki discuss techniques of ballot design derived from psychometrics that minimize these psychological effects, such as asking voters to give each candidate a verbal grade (e.g. "bad", "neutral", "good", "excellent") and issuing instructions to voters that refer to their ballots as judgments of individual candidates. Similar techniques are often discussed in the context of contingent valuation.