Smells can do a number on your brain. If, say, your family room feels cramped, don’t call a contractor. To trick your mind into thinking the space is larger than it is, break out a green-apple fragrance. Sound crazy? It’s not, says Alan Hirsch, founder and neurological director of the Smell & Taste Treatment and Research Foundation, a Chicago-based organization that studies the effects of scents. Hirsch asserts that smell can change a person’s perception of her surroundings. Here are a few more of his “functional fragrance” suggestions.

To Make the Room Bigger: Like green apple, Hirsch says, the smell of cucumber creates a subconscious perception that surroundings are more spacious than they are.

To Add Homeyness: Want guests to feel welcome? Hirsch says vanilla elicits “a feeling of safety and comfort.” Baking cookies or bread works, he says, since most people associate baking smells with positive memories from childhood.

To Suppress the Munchies: If you tend to nibble as you cook, a peppermint scent in the kitchen will curb your urge to nosh, Hirsch says. Not mad about mint? Banana also does the trick.

To Fire Up Your Workout: Buttered popcorn is the scent to turn to if you want an energy boost while exercising. Hirsch says the scent of strawberries also gives exercisers more spring in their step.

To Get Smart: Once you’ve outfitted your home office with a flat-panel computer monitor and a powerful modem, add a bouquet. Says Hirsch, “We found a mixed floral smell increases learning speed.”