Table 1.

Items measuring hypothetical portion size selection and proposed mediators.

Measures	Items
Hypothetical portion size selection	1. ‘how much of this (lasagna/spaghetti) would you choose to eat for lunch?’ [7]
Perceptions of general portion size normality	1. ‘how much of this (lasagna/spaghetti) would you say is normal to eat for lunch?’ [7]
Perceptions of descriptive social norms (lasagna: Cronbach’s α = 0.92; spaghetti: Cronbach’s α = 0.94)	1. ‘how much of this (lasagna/spaghetti) do you believe other (sex) aged (age) years would choose to eat for lunch?’
	2. ‘how much of this (lasagna/spaghetti) do you believe most (sex) aged (age) years would choose to eat for lunch?’
Perceptions of injunctive social norms (lasagna: Cronbach’s α = 0.89; spaghetti: Cronbach’s α = 0.90)	1. ‘how much of this (lasagna/spaghetti) do you think other (sex) aged (age) years believe that you are supposed to eat for lunch?’
	2. ‘how much of this (lasagna/spaghetti) do you think other (sex) aged (age) years believe that is the appropriate amount to eat for lunch?’
Personal norms (lasagna: Cronbach’s α = 0.90; spaghetti: Cronbach’s α = 0.91)	1. ‘how much of this (lasagna/spaghetti) do you personally believe is a normal amount for you to eat for lunch?’
	2. ‘how much of this (lasagna/spaghetti) do you personally believe is an appropriate amount for you to eat for lunch?’
Expected satiety (lasagna: Cronbach’s α = 0.90; spaghetti: Cronbach’s α = 0.91)	1. ‘how much of this (lasagna/spaghetti) would you need to eat to feel satisfied?’
	2. ‘how much of this (lasagna/spaghetti) would you need to eat to feel full?’