As a career college instructor I have noticed that diffrent students need to be motivated in diffrent manners. and it is not determined by age,race, gender,ect. but by indivual needs.some of the students who are making a career change might need to be motivated by diffrent tequniques.sometimes positive reinforcement might be you telling them that they are doing good, but also they might be set in there ways. After a career change you might have get the student to look things in a diffrent prespective which might not be a motivation issue.unless they hit a wall. then the instructor should be ready to help the student break thru the wall