Here Italian Prime Minister, Silvio Berlusconi is shown "adjusting" the knot in his tie - however this is a False Tie Adjust. It is performed at times of considerable anxiety, concern, emotional discomfort, fear, worry or vulnerability. Fondling a necklace in this same area is a common female equivalent, although women in an similar emotional state will often touch this portion of their neck (known as the supra-sternal notch) even if there is no clothing covering it, nor any necklace present (Navarro). Such self-touching is an example of a Manipulator/Adaptor/Pacifier (MAPs). It is highly recommended that leaders avoid this gesture and other MAPs in public.
Note Mr. Berlusconi has a fairly sincere smile. When a signal of comfort (here, a sincere smile) coexists with a signal of anxiety (false tie adjust) - it is the anxiety which is truly being experienced emotionally. Silvio is a professional and is skilled at smiling on demand - but professionals are human too - and thus while one sign can be "masked" - they all cannot...and behold, the truth slips out!