Putting humans in situations where failing to notice something results in catastrophic consequences is bad engineering, not human error. I am very glad that no-one is pointing at one, or either, pilot or flight-crew's actions or inactions and saying pilot/human error.
The human visual system is good at picking up movement across the visual field. As other have pointed out, if the two aircraft were on intersecting vectors, there would be no relative movement to be picked up. Bright(er) lights don't help: if anything, they make it harder to make out the source from the background, as the bright light makes the local background look like a uniform dark field.
From a 'human factors' point of view, if you have an incorrect situational awareness model in your consciousness, it is difficult to remain flexible enough to recognise you might be wrong - misidentifying the next in sequence, AAL3130, landing runway 1, as the CRJ (IF that is what happened) is hard to recover from.
We should not blame the flight-crews. We should not engineer them into situations where incorrect interpretation of what were likely inputs that were easy to interpret in more than one way become catastrophic. The problem is not restricted to air-navigation. One of the
many reasons Norway lost the frigate
Helge Ingstad in a collision was misidentification of a moving object (a brightly lit oil tanker) as a stationary object (an oil terminal), and incorrectly ascribing radio transmissions as coming from other moving ships in the vicinity,
The personnel on the bridge of
Helge Ingstad both before and after the change of watch 20 minutes before the accident were of the opinion that the lights they saw from
Sola TS were from a stationary object in connection with the
Sture Terminal, and not from an oncoming ship. Contrary to the
International Regulations for Preventing Collisions at Sea,
[60] "Sola TS" had the same deck lights on after the ship left as when they were still at the terminal. The personnel on the bridge of
Helge Ingstad were of the opinion that the radio call just before the accident was from one of the three other oncoming ships.
We should look at how to engineer things better to avoid this happening: this does not mean 'more training', 'brighter lights', or putting additional human-operated steps in already complex procedures.