Hey everyone,

I’ve been trying to model a common real-world relationship dilemma using behavioral economics frameworks, and I’d love to get this community's take on how to map the utility functions and strategic equilibria here.

The Scenario:

A girl operates under a tight liquid budget constraint of £100 cash (she earns a wage of £10/hour).

• Action A (High WTP): She willingly drops £30 cash (30% of her net worth) plus 1 hour of leisure time to play padel with two friends.
• Action B (High WTA / Avoidance): For 9 months, her boyfriend has consistently requested a small, low-cost signal of effort: for her to bake him a simple batch of cookies. The objective market cost is negligible (£5 for ingredients + 30 mins of labour, representing a £5 opportunity cost).

Despite his constant requests—and despite the fact that the boyfriend aggressively over-supplies effort by fulfilling every single micro-request she has—she completely refuses to do it.

When the boyfriend challenges her on the math (spending 8 hours of labour equivalent on an £80 pair of jeans vs. 30 minutes on him), she uses a few classic behavioral defence mechanisms:

1. Projection Bias: She claims that verbal praise and physical affection are "enough" for the relationship, projecting her own utility weights onto his.
2. The Phantom Promise: If he offers to shift to market norms by saying, "I will literally bank transfer you £20 to do it," she suffers from social shame and issues a time-inconsistent promise: "No, don't pay me, I'll do it myself." Then, she defaults right back to the baseline and never executes.

My Behavioral Breakdown:

• 1. Hyperbolic Discounting & Present Bias: The immediate transaction utility of padel (instant dopamine, social status, peer bonding) heavily outweighs the delayed, abstract utility of relationship investment, which she already views as a "fully funded account" due to the boyfriend's over-supply.
• 2. The Endowment Effect & Asymmetric Loss Aversion: Because her budget is low (£100), she is highly loss-averse regarding her cash and immediate free time. Giving up £5 and 30 minutes feels like a painful, visceral loss of her current endowment. The boyfriend is looking at the gain (relationship harmony), while she is looking strictly at the loss of autonomy.
• 3. Market vs. Social Norms (The Ariely Effect): Introducing a cash incentive (£20) crowds out the social norm, triggering an ego-preservation mechanism. She uses a "Phantom Promise" to buy immediate relief from the argument, heavily discounting the future cognitive cost of actually having to bake.
• 4. A Monopoly Equilibrium: From a cold, profit-maximizing perspective, why would a rational consumer change this setup? Her input cost is £0, and her output is a doting boyfriend who gives infinite effort. Her ROI is mathematically infinite. By making his effort a zero-priced good, the boyfriend has accidentally lowered its subjective value to her to zero.

Questions for the Sub:

1. How would you formally write out her utility function to include this massive "psychic cost/dread tax" ($D_b$) for domestic relationship labour vs. her self-image mental account (£80 jeans)?
2. If the boyfriend wants to break this Nash Equilibrium, what is the most efficient "Nudge" or structural choice architecture change he can implement? Should he introduce strategic scarcity of his own effort to reset her baseline reference point?