Even though you can’t read minds and don’t want to ask directly, you can learn to detect the signs that someone has romantic feelings for you. Scientific and sociological studies have identified several physical and psychological behaviors that reveal amorous interest. Any one sign could be coincidental, but if your friend displays multiple signs of subconscious attraction, he might be hiding a secret crush on you.

If your friend smiles when talking to you, and his smile seems especially large or bright, he might have a crush on you, notes students contributing to a 2008 health and wellness project at Brigham Young University - Idaho. People often smile joyfully, usually as a subconscious act, when they feel excited to be around the objects of their affection.

Making frequent, earnest eye contact can signify a crush. Normally, people’s eyes tend to wander around the room, so looking at just one thing indicates an unusual focus of attention. A high level of eye contact demonstrates attraction and a feeling of intimacy, concludes a 2006 article published in Human Communication Research, titled "Relational Messages Associated with Nonverbal Behaviors," written by Judee K. Burgoon, David B. Buller, Jerold L. Hale and Mark A. de Turck. If your friend's eyes stay on you, she might have romantic feelings for you.

Playing with hair often indicates a crush. This is true for both genders, according to Jan Hargrave, author of "Let Me See Your Body Talk." The playing with hair could show a subconscious desire to draw your attention to a prized physical trait, or it might simply arise from nervousness, which many people feel when they try to hide romantic attraction. A person who has a secret crush may also squeeze or fidget with clothes, jewelry, or other objects.

If your friend touches you frequently, he might have a secret crush on you; especially in combination with other signs of romantic interest, touching demonstrates attraction, according to the article written by Burgoon, et al. Even if your friend's touches seem platonic and benign, the fact that he initiates physical contact can indicate physical attraction.

Sitting or standing close to you signifies a secret desire to be near you. If your friend invades your personal space more than social norms specify, he probably harbors romantic attraction for you, suggests contributing writers at Brigham Young University - Idaho. Leaning toward you increases this signal’s potency. The combination demonstrates attraction and emotional closeness, notes Burgoon, et al.

If a woman crosses her legs and arranges them so that they point toward you, her body language is communicating subconscious attraction. Kicking her leg slowly intensifies the sensual nature of her posture, according to Hargrave.