The IKEA effect refers to the phenomenon where people value products more highly when they have invested labor in creating them. In four studies, researchers found that participants who assembled IKEA boxes, folded origami, or built sets of Legos valued their self-made products more than identical pre-assembled products. Participants saw their amateurish creations as similar in value to expert creations and expected others to share their opinions. The IKEA effect was observed only when labor resulted in successful completion of tasks; when participants built and then destroyed their creations or failed to complete them, the effect dissipated. The effect was also observed for both "do-it-yourselfers" and novices. The study suggests that labor leads to love when it results in successful completion of tasks. This is supported by research on effort justification, which posits that the more effort people put into a task, the more they value it. The study also highlights the importance of successful task completion in increasing valuation. The researchers manipulated the success of labor in several ways to test their model, exploring when and why labor leads to love. In Experiment 1A, participants who assembled IKEA boxes valued them more highly than identical pre-assembled products. In Experiment 1B, participants who created origami valued their creations more than others. In Experiment 2, participants who built and then unbuild their creations showed lower valuations, indicating that successful completion is crucial for the IKEA effect. In Experiment 3, participants who completed half of the steps to build an IKEA box valued it more than those who did not complete it. The study concludes that the IKEA effect is a fundamental human need for effectance, the ability to successfully produce desired outcomes in one's environment. The effect is not solely due to customization or idiosyncratic tailoring of creations to preferences. The psychological process by which labor leads to love requires successful completion of labor. The study also highlights the importance of task completion in increasing valuation and the role of effort in increasing liking for the fruits of one's labor. The findings have implications for marketers considering engaging consumers in co-production.The IKEA effect refers to the phenomenon where people value products more highly when they have invested labor in creating them. In four studies, researchers found that participants who assembled IKEA boxes, folded origami, or built sets of Legos valued their self-made products more than identical pre-assembled products. Participants saw their amateurish creations as similar in value to expert creations and expected others to share their opinions. The IKEA effect was observed only when labor resulted in successful completion of tasks; when participants built and then destroyed their creations or failed to complete them, the effect dissipated. The effect was also observed for both "do-it-yourselfers" and novices. The study suggests that labor leads to love when it results in successful completion of tasks. This is supported by research on effort justification, which posits that the more effort people put into a task, the more they value it. The study also highlights the importance of successful task completion in increasing valuation. The researchers manipulated the success of labor in several ways to test their model, exploring when and why labor leads to love. In Experiment 1A, participants who assembled IKEA boxes valued them more highly than identical pre-assembled products. In Experiment 1B, participants who created origami valued their creations more than others. In Experiment 2, participants who built and then unbuild their creations showed lower valuations, indicating that successful completion is crucial for the IKEA effect. In Experiment 3, participants who completed half of the steps to build an IKEA box valued it more than those who did not complete it. The study concludes that the IKEA effect is a fundamental human need for effectance, the ability to successfully produce desired outcomes in one's environment. The effect is not solely due to customization or idiosyncratic tailoring of creations to preferences. The psychological process by which labor leads to love requires successful completion of labor. The study also highlights the importance of task completion in increasing valuation and the role of effort in increasing liking for the fruits of one's labor. The findings have implications for marketers considering engaging consumers in co-production.