Appeal after clarity

Claim: decoration stays only when it carries the message and alters no quantity; polish comes after the other figure rules hold, and never replaces them.

• Grade: supported with caveat (the meta-analyses are measured, for interfaces).
• Evidence: review, strand 3; against, Minimalism against embellishment.
• Check: figure-judgment (judgment): does any decoration distort a quantity or compete with the message?
• Reader styles: none changes it.

What it asks

• Apply the other figure rules first; then choose type, colour and spacing that look good.
• Keep an image or an ornament only if it says the message.

Why

Beauty gives a small gain in performance with interfaces: g = 0.12 over 25 studies (Thielsch 2019), g = 0.29 over 31 (Schlamann 2026). Embellished charts were described as well as plain ones and remembered better weeks later (Bateman 2010), while other embellishments slowed search or lowered accuracy (Borgo 2012; Skau 2015). Material that is interesting but irrelevant lowers learning (Cheng 2026).

Limits

• Bateman 2010 used 20 students and charts by one designer (Few 2011; Kosara 2010).
• No study tests appeal in a node-link diagram.