Why do the main characters call each other by their last name only?

Question

Watching the German version of The Mentalist on Netflix I discovered something that seems strange to me:

Whenever someone of the core CBI team member talks to another team member, they only refer to each other by their last name.

E.g. when Patrick Jane talks to Teresa Lisbon he might say:

Hi Lisbon, …

I.e. he does not say:

Hi Teresa, …

Nor does he say:

Hi mrs. Lisbon, …

(I'm only watching the German dubbed version, I would expect the behavior to be the same in the original US version).

I do consider it disrespectful to call someone by her/his last name only.

So my question:

What is the reason behind the CBI members only calling each other by their last name?

Answer 1

Whilst you consider it informal, in many parts of the world it is quite common.

For example, sports stars are often referred to by their surnames. In military or police settings, surnames are often used (e.g. Private Martin, or just Martin). In many old-fashioned private schools, surnames are used.

There are a variety of possible reasons for this, but usually it relates to either:

1. Depersonalising a situation
2. Demonstrating authority
3. Separating people by using surnames rather than more-common first names
4. A combination of the above.

In a sports setting, it's simply far easier to refer to people by surnames, as they're more distinctive. Now, for particularly famous people this might not be the case (think Cristiano, or Kobe, or Lebron. But for the majority of others, it's far more distinctive to use a surname.

In a school setting (particularly traditional private schools), it both personalises and separates out people. Rather than having a class with five "James"s, teachers used surnames to distinguish between them. It also created a more authoritative atmosphere which was used to help control classrooms.

Finally, in your military/police setting it's likely to both depersonalise a situation and demonstrate authority. It shows that everything is not immediately "chummy", but that authority and respect of authority is key.

If you search online, you'll find many, many shows following this pattern.

Answer 2

In the context of this show, I just wanted to add another perspective to this.

In S1E5, when Jane tells Lisbon that the murderer smelled like Pineapple, this is how the conversation went:

Lisbon: Hey

Jane: Pineapple. He smelled like pineapple.

Lisbon: What the hell... flashback

Lisbon: Okay, good. Listen, tell Rigsby Teresa needs help.

Lisbon: Me? I'm at the Eagle Pine Lodge off Route 6.

This suggests to me that she was using Teresa as a handy codename, at least in this particular scene.