We know psychology as marketing engineering is successful - it is a giant industry, we even have advertising here on Science 2.0. And it's being used in restaurants right now to get you to spend more money.
Professor John Edwards, Theme Leader of Food Service&Applied Nutrition in the International Centre for Tourism&Hospitality Research at Bournemouth University, gets cited by Amy Fleming in The Guardian for determining the optimal number of menu items per category; too few and people feel their choices are limited, too many and it feels like fast food. What are those numbers? 6 items per category in a lower-end restaurant while 10 courses book-ended by 7 starters and desserts, was ideal for fine dining.
Brian Wansink has also studied menu engineering while William Poundstone is highlighted for annotating the menu from Balthazar in New York to in order to show the marketing bells and whistles it uses to herd customers into parting with the most cash.
Of after-dinner note was a factoid from Malcom Gladwell: while most Americans say they prefer a dark roast, only 25% actually do in taste tests. Aspiration, peer pressure and marketing messages make the difference.
Restaurant menu psychology: tricks to make us order more by Amy Fleming, The Guardian