Perceptive preference toward recycling bin designs: Influential design item depending on waste type, the impact of past perception experiences on design preference, and the effect of color design on waste separation.

Efficient waste separation using recycling bins designed appropriately is promising for waste recycles. This study investigated recycling bin designs, in particular color and insert slot, and quantified perceptive preferences toward designs. This study hypothesized that design preference toward recycling bins is affected by past perceptions of recycling bin designs. Design categorization survey for 240 recycling bins used in public spaces shows that popular colors depend on design items and waste types. This study found that highly preferred colors were consistent with frequently used colors in certain design items, which was slot frame color for combustible and incombustible waste bins, and body color for PET bottle bins. Color preferences had statistically significant correlations with color usage rates (p = 0.009 for combustible waste bin, p = 0.032 for incombustible waste bin, and p = 0.012 for PET bottle bin, respectively). Although insert slot shape had moderate but significant correlations between slot shape preference and usage rate of slot shape (p = 0.002 or less for all recycling bins), the preference was mainly affected by slot largeness for combustible and incombustible waste bins. According to these results, this study concludes that the hypothesis was supported in particular for color preference. On the other hand, on-site experiments showed that the effect of only "impressive" color was too weak to improve waste separation. To encourage waste sorting using well-designed recycling bins, combination of preferred design items is necessary. Intensive usage of well-designed recycling bins for frequent perception opportunities is recommended as an environmental feedback to support sufficient design preference.