Final answer:
Lighter highlights at the temples can create the illusion of width for a client with a narrow forehead, enhancing the overall balance of facial features.
Step-by-step explanation:
Lighter highlights may be used at the temples on a client with a narrow forehead to create the illusion of width. When applying lighter colors or highlights to the hair around the temples, it can give the appearance of a wider forehead, thereby balancing facial features. This technique is often used in hair styling and makeup to enhance the client's natural features and create a more aesthetically pleasing look.