Question: Which way are arrows supposed to point on a tabbed web page? Towards the selection or towards the body of the selection? An awkward scenario seems to arise when a user selects another item and the arrow moves to point at nothing in particular when the arrow is pointing to the body. Is there a best practice? 

![enter image description here](https://i.stack.imgur.com/WgSMw.jpg)

Answer: 
Which relationship do you want to emphasize? Use that to inform your decision. The down arrow in your image indicates a relationship of "is title of" or "is detailed by" or even "has child", whereas the up arrow indicates a relationship of "is detail of" or "has title" or even "has parent". 

I suspect the down arrow is more common and thus familiar to more users. In CSS selectors, for example, the ">" operator is for the "has-child" relationship (points from parent to child). Is your user domain consumers? Then I would consider the down arrow. Only for IT or math domains/users have I frequently seen an arrow point from child/leaf back to parent/owner.

On the other hand, especially if your domain is new or unusual, you could remove the directional question with a nondirectional or bidirectional solution.

Spotify Help has a nondirectional highlight between the selection and body:
<https://support.spotify.com/us/>

![enter image description here](https://i.stack.imgur.com/JxhsS.png)

Essentially:

![mockup](https://i.stack.imgur.com/ieQfX.png)

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A "down" arrow points to the headline, which directs a user's eyes and attention to follow it toward the text below. If your goal is to get them to read the text, that's a good visual cue. 

The "up" arrow has the opposite effect, pulling the reader's eye back to the nav bar. 
Option 2 has me constantly going back to read "Item" instead of the headline or copy below. 
That's probably not what you want. 

As for having the arrow point at "nothing in particular" that's a valid point. Using an "up" arrow instead doesn't really seem to solve the problem, for the reason described above. It still might be preferable to point downward, if not directly at the headline, at least toward the body text. 

You could also use highlighting or contrast/color as already suggested to simply indicate the "active" tab.