Meaning of the phrase "causal arrow point" in context

Question

It was in an online journal, Psychology Today, by Hal Herzog. Here is the piece of the article:

In their article, Westgarth and her colleagues suggested it is possible that some unknown pattern of behavior in emotionally unstable people makes them especially prone to dog bites. But they also point out that other factors might be involved. For example, anxious people might be more likely to have nervous dogs. Or the causal arrow point could even point the other direction and being bitten by a dog could make people more fearful and anxious.

What does that mean there and why has the definite article been used before that phrase?

Answer 1

The author could simply have said:

Or the arrow could even point the other direction...

Instead of arrow he used the more specific (but unusual) arrow point, and he added causal to indicate that the arrow indicates a causal relationship.

What he says is: instead of "they get bitten because they have nervous behaviour" (the cause is their behaviour, arrow from people to dogs), it might be that "they get bitten because they have nervous dogs" (the cause is the dog's behaviour, arrow from dogs to people).

BTW I do not completely agree with the author that the arrow now points in the other direction. After all, the suggestion is that their behavior made the dogs nervous in the first place, so they are still the (indirect) cause. There are two arrows here (people -> dogs, then dogs -> people).