How are you adjusting reinforcement to reduce maladaptive behavior? Can you reinforce a more appropriate, alternative behavior to replace the maladaptive behavior?
Clearly, for the student who wants to be left alone (who rejects rudely any overture), the practice of this skill may be quite painful at first. Provide frequent breaks where he gets to engage in favored solitary activities. For the student who naturally approaches interaction but who may be excessive in his overtures, the practice itself may be rewarding. Your differential labeling of good trials and response sequences may serve as adequate reinforcement.
Reinforcement theory is quite clear: if a behavior is reinforced just occasionally, it will increase in frequency. Think about this in relation to the student who makes repeated friend requests on Facebook, who makes an invitation to others repeatedly and who experiences that once in a while, that persistent asking gets a positive response from someone. That strategy of asking over and over works just enough of the time to sustain the pattern – a pattern that you want to reduce. For this student, please consider strong external reinforcement in the form of privileges or special activities for using the strategy of asking once. Provide ample social praise and, if possible, engage valued peers in those opportunities for social praise of the expected behavior of asking once.
Are you using labeling and social praise to make the contingency between desired behavior and reinforcing consequence clear to the student?
What reinforcing consequences can you arrange that are more naturally or intrinsically connected to this targeted behavior?