Negotiating when logic isn’t leading: Practical ways to handle “irrational” behaviour

This article builds on a question put to me in a recent seminar: “What do you do when the other side simply isn’t behaving rationally?” You prepare well, you present clear options—and yet the other side rejects workable solutions, changes direction without warning, or argues from emotion rather than evidence. Many negotiators call this “irrational” behaviour. Below is a clear way to think about it, how to spot it early, and ten practical moves that keep progress possible.

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What do we mean by “irrational”?

“Irrational” here does not mean that a person is unreasonable in all areas of life. It means that in this negotiation their behaviour does not serve their stated interests. Drivers can include strong emotion overriding evaluation, “all-or-nothing” thinking, threats to status or identity, sunk-cost effects (continuing because you’ve already invested time or money, even when the facts now argue for a different course), suspicion of motives, and process disruption (late surprises, rotating agendas, performative urgency). Treat it as a situation to manage, not a personality to judge.

How to recognise it early

You’ll usually sense it first in the tone and texture of the conversation. Language becomes absolute—“never”, “always”, “non-negotiable”—and reasons arrive as declarations rather than explanations. As you address one concern, the target shifts to another; acceptance keeps moving just out of reach. Evidence stops being something you examine together and turns into something to be waved away. Small cues around status start to matter more than they should: who speaks first, how an email is worded, whether a title is used.

Time pressure often enters theatrically: urgent demands appear without warning, followed by long pauses, then fresh urgency. The process itself becomes unstable—agenda changes mid-stream, topics are re-opened after being parked, or someone performs a dramatic exit to signal strength. Sometimes you’ll also feel a mismatch between what they say their goals are and what they push for in the room, a hint that unseen incentives or audiences may be steering their choices.

When several of these threads appear together in a short span, take it as a sign to change pace and adjust the process. Stay courteous, slow the conversation slightly, and switch from arguing points to exploring consequences and options. You are not conceding; you’re creating conditions where sense can surface again.

Ten practical moves

1) Describe the pattern, not the person: State what you observe in neutral, face-saving language and suggest a small adjustment. You’re solving a process problem together, not accusing anyone. Calm, specific wording lowers defensiveness and gives both sides something practical to accept.

2) Lower the temperature before you reason: People absorb little when emotions run high. Slow your pace, simplify your sentences, and use short pauses—or a brief break—to reset the room. Think of composure as a tool, not a mood: your steadiness invites theirs.

3) Acknowledge the concern precisely: Vague “I understand” can feel hollow. Name the specific worry you hear and check you’ve got it right. When people feel accurately heard, they stop arguing with your motives and start engaging with your ideas. Precision here saves time later.

4) Shift from positions to consequences: Rather than debating who is right, ask what happens next under each option: what improves, what becomes harder, what risks change. Consequences bring interests back into focus without forcing anyone to back down. Capture answers visibly; it signals seriousness and builds a shared record.

5) Make the decision smaller (and safer): Big yes/no choices feel risky. Break the decision into a short trial, a limited scope, or a time-boxed step with a clear review date and the right to adjust. A simple pattern works well:“Step 1 for two weeks → review together → decide Step 2 or stop.”Smaller steps reduce fear and create momentum.

6) Use independent standards: Suggest clear criteria that both sides can accept—benchmarks, regulations, past practice, simple metrics—and test proposals against them. When a neutral yardstick carries part of the load, the discussion feels fairer and less personal, which keeps emotion from driving the outcome.

7) Change the process, not just the message: If the conversation keeps stalling, adjust the setup: who is present, the order of topics, meeting length, or whether you split into smaller groups. A short session chaired by a neutral colleague can sometimes achieve more than a long, tense meeting at the same table.

8) Trade empathy for information: Create a moment that feels safe for openness—a short side conversation, or five minutes “off the record”—and ask one clean question about incentives or constraints. Listen fully. Real movement usually depends on understanding what truly matters to them but hasn’t been said aloud.

9) Offer choices that preserve dignity: Present two or three viable paths that allow the other side to look competent to their stakeholders. When face is protected, flexibility increases. Design options so each one is respectable, even if they prefer only one of them.

10) Make outcomes—and risks—concrete for both sides: Reality-test politely: outline near-term effects if you pause versus proceed, link them to each side’s goals, and keep the tone factual. You’re not threatening; you’re forecasting. Shared clarity about consequences often unlocks a practical next step.

A brief note on 3D thinking and sequencing

When behaviour turns “irrational”, arguing harder across the table has limited value. Step up a level:

• Setup: Are the right people involved, and in the right order (this is sequencing—planning the order in which you approach people, issues, and offers to build momentum and reduce resistance)? Are decisions influenced elsewhere?

• Deal design: Can you reshape value—risk-sharing, pilots, options, safeguards—so that the sensible choice also feels safe?

• Tactics: Use questions, framing, and anchoring once the conditions above support them.

Final thought

If they’re still at the table, progress is possible. Change the conditions—cool the room, protect face, and plan the order of people, issues, and offers—and reason will have space to land.

Next step: If you’d like practical drills and templates for these moves, book our Advanced Negotiation training or ask for a short 90 minute online webinar/workshop for your team.