Why don't you take a picture, it'll last longer.
Target fixation can happen to anyone whether driving, riding motorcycles or ripping laps on a Motocross track. A good trainer rails against it and you can often distinguish the rookies from the veterans riding dirt bikes.
The importance of looking ahead comes into play to prevent target fixation as this circumstance often occurs when a rider fixes their eyes on a potential hazard and zeroes in on it - dirt bike riding 101. Riders under the spell describe target fixation as a circumstance where they almost become hypnotized by the hazard, perhaps a large rock, and they can't take their eyes off it. Where the eyes go the ride goes and this usually results in the bike running into or over the imminent danger.
Wikipedia describes target fixation as an attentional phenomenon where a person becomes so focused on an object they inadvertently increase their risk of colliding with the object. This often occurs in high-speed situations such as motorcycle riding.
A motorcycle rider on the street might fixate on a distraction or potential hazard to avoid only to ride into it. Likewise, someone on a dirt bike might completely focus on a downed tree while on the trails or some gnarly ruts on the track.
If you have not experienced target fixation, you might wonder why the rider simply doesn't move out of the way of the very hazard they want to avoid. Think of it like tunnel vision which can happen under intense conditions. Until you put yourself in a high speed, high stress situation you won't understand what happens to the brain. But knowing about target fixation offers the first step in preventing it from happening.
Avoiding Target Fixation
Police officers regularly train for high stress situations so when the time comes they can manage the encountered problem far better than if they went in cold. Likewise, you need to put yourself in a high stress situation on the Motocross track to train your brain to keep looking ahead and not concentrate on a single solitary object.
Therefore, in the early stages of training, you probably will encounter target fixation but the more you practice the better you can prepare yourself to handle future scenarios and avoid potential problems. Eventually, you will recognize the situation and pull yourself out of the condition before the collision.
Ultimately, you want to make target fixation a thing of the past if it becomes a problem for you. Therefore, you need to work on looking ahead and stop looking down just past the front fender. Looking ahead at where you want to go prevents you from fixating on a potential hazard. By looking ahead, you will have already seen the potential object of fixation and made the necessary adjustments to avoid it.
If target fixation continues to affect your riding find a trainer to help you focus, or at least in this case, not focusing on specific objects. Good MX coaches and trainers find your weakness as a rider and work with to resolve those issues keeping you off the podium.