Below are 3 reasons not to yawn in an interview:
Reason #1 It can highlight poor time management
If you must explain that you were still up at 2am researching the company, it displays poor time management. Your interviewer will not be impressed by you leaving everything to the last minute and this does not augur well for the future.
Reason #2 It can be interpreted as you taking the interview lightly
By being so relaxed and laid back in an interview, you let out a yawn, the interview can interpret this that you are not taking the company or the interview seriously.
Tip #3 A yawn may cause offence
Picture this. Your interviewer is in the middle of saying something that they feel is very pertinent and relevant to the role and they expect your full attention. You commence a yawn as they are speaking. Your interviewer is likely to take offence and may think that you find what he/she is saying is boring.
The best advice is to avoid yawning in interviews by conducting your research well in advance and getting a good night’s sleep the night before your interview. If all else fails, a strong coffee just before your interview should do the trick.