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: 
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.
Arrow pointing down is the right way. 

I am sure the focus here was the arrow direction, I am just covering related points:  

There are a couple of incorrect usages in this sample. 
The top rectangles are like switches with bulbs embedded inside them. 
When you press, they should light up. Here, they become dark. The untouched buttons are brighter. Maybe suitable for a page about blackholes in astronomy. 

Page title font size is somehow not fitting, between the title and body. There is no progressiveness. 

The reason for the arrow direction is, they are like pointers, think street signs in old towns. They point to where the real thing is.