Go here for these superb one line sound bites describing each of these psychological traps in negotiation...
∗ People tend to "see" what they expect and wish to see, and what is in their self-interest to see.
∗ People mostly place unwarranted confidence in their own prediction about future events / People usually underestimate the importance of what they do not know.
∗ People tend to attach greater weight to prospective losses than to equivalent prospective gains.
∗ When something belongs to us, we tend to attach a greater-than-market value to it because it is ours.
∗ People often devalue a proposal received from someone perceived as an adversary, even if the identical offer would have been acceptable when suggested by a neutral or an ally / A concession that is actually offered is valued less than a concession that is withheld.
∗ Opportunities generally seem more valuable to us when their availability is limited.
Anchoring and adjustment
∗ People who hear high or low numbers as initial starting points are often affected by these numbers and unconsciously adjust their expectations in the direction of the opening number.
Attribution bias / Similarity principle
∗ Most people tend to believe others are like themselves / We tend to trust people who appear more than less similar to us.
Fundamental attribution error
∗ There is a common tendency to ascribe other people's behavior to their personality rather than to the situation they are in.`
And if you're impressed by that, you will surely flip over this treasure trove of 20+ one page negotiation think pieces that are just the thing for your mediation resource folder - from Swiss consultancy, Sumbiosis.
They range from;
Alliances to Animosity to Manipulation to Nonverbal to Trustworthiness to Turnaround