Why a shared table changes what people order

Six people, one waiter, one circuit of the table. The first person orders the fish. By the time the sixth speaks, four dishes are taken, the price band is established, and the sixth chooses something they would not have chosen alone and enjoy less.

What everyone sees

Ordering is treated as six independent decisions that happen to occur in one room. They are not independent. Each order is public information for the people after it, and the sequence imposes both a reference range and an unspoken requirement for variety that nobody in the group would defend if asked.

What is actually happening

Ariely and Levav ran studies in a bar and in the laboratory and found that sequential public ordering produced more variety within groups than private ordering did, and that the people who diverged to maintain that variety reported lower satisfaction with what they received — the variety serving a group function at individual cost. McFerran, Dahl, Fitzsimons and Morales examined the influence of a fellow diner’s choice and found that portion and item selection shifted towards the other person’s, with participants unable to identify the influence afterwards. The two effects operate in different directions on the same table. People converge on the range and diverge on the item, and neither adjustment is available to introspection.

Why it stays hidden

The influence hides because each person can give a reason. I felt like something lighter, I did not want two of the same. The reason is genuine and arrived after the constraint. Order the same six people privately and the distribution changes, which is the only way to see it — and no table is ever run twice.