While we want out horses to enjoy comfortable, fear free lives, the truth is there is stuff out there that scares them. They are prey animals after all; a banquet for the wolf pack. If we want to stay safe and help our horses feel safe, we need to be a help, not a fright!
Scary stuff in and of itself is a broad range of things and situations - from the mildly unpleasant that provokes only small and transient hikes of the stress response to all out fight/flight or shutdown in death faint because life has to be fought for, or it's done for. Fear is in the experience of the beholder - right within the viscera of the body as well as the startled mind. Every day equestrian equipment, and its certain usage can provoke feelings of fear. So can everyday activities as well as those that are more out of the ordinary.
Make a list of the things your horse fears. That might include the cattle that are sometimes on the pasture down the road. That bend in the lane where you once met a what appeared to be a re-enactment of the Tour de France. Sudden realization of severe bit pressure when your horse lost balance and rushed or spooked on an exhilarating ride. All the best and worst emotional experiences happen when the adrenalin is rushing. Your list might end up chock full o variety of fearful objects, places and events but there are just 3 things your horses needs you to know about them:
When are they going to happen?
When are they going to end?
What can I do to avoid them or make them go away?
Being afraid is stressful. Obviously. A bit of stress, successfully dealt with helps horses to be more robust and surer of themselves as confidence in their personal ability to deal with threatening situations grows. They have lived to fight another day! Unpredictable and unavoidable stresses cause unpleasant effects on equine welfare: anxiety and depression to name but two. Clearly living a life with a lot of fear in it is very unhealthy and can hardly be called a good life. But being able to live a completely fear free life is highly unlikely, especially when you are a horse! It's how much fear, and how often, how predictable and controllable it is that counts when it comes to equine mental health.
Let's go back to those 3 things. Clearly it helps if the horse:
Receives a reliable warning signal
The duration of the event is predictable
The situation ends as a consequence of a particular behaviour - the horse might not be able to avoid it turning on, but he can turn it off
You may have already witnessed this in action: say your horse is approaching that bend in the lane where you met a speeding peloton of MAMILs heads down and pedaling furiously while talking very loud. Because the event happened at the bend, the bend has automatically become the warning signal for scary cyclists. Probably this warning signal is working for both of you - you might tense your seat or your reins as you listen out for cyclists over the hoof beats on the tarmac. The place, however, is not a reliable enough warning signal on its own - you have both ridden this stretch of road without cyclists threatening your existence plenty of times. So your horse is still on high alert, and so too, might you be. Your horse needs more concrete warning. He might begin to worry more in other places in case there are bicyclists there too.
The BHS "be nice, say hi" campaign springs to mind and you can own this as a rider. By getting in there early, with a nice happy smile and a clear, "hello", you can attract the attention of at least some of the cyclists you encounter on your rides and engage a nice exchange of words. Positive social behaviour helps us feel safer and it will rub off on your horse.
Taking this further, the duration of events, and the escape or avoid actions of your horse might occur with more reliability which you can also tap into. Bikes pass in a reasonably similar time frame to each other. Escape and avoidance behaviour in general are very useful for bringing back a sense of control to your horse - really important for his mental health. It is a matter of what behaviour when it comes to our safety when riding out!
Napping is a common avoidance behaviour attempted by horses. They don't feel safe because they don't know what will happen next because of those unpredictable warning signals - so they refuse to go. They might be overwhelmed by another set of warning signals and avoidance behaviours. Firm leg aids backed up by a stick can be avoided by walking on. Walking on keeps the horse safe from more escalating forwards aids. But only if walking on is considered by the horse to be the lesser of two evils. Some horses will prefer to avoid harsher aids and also discover that by continuing to walk on, that bikes pass on by because they have kept walking. Over repetition the horse may then worry less about bikes because none ever hurt him.
Or this might never happen. In this scenario we are putting the horse between a rock and a hard place. The rider's aids turn out to be softer than the hard place - no matter how much the rider escalates them. This is especially the case where the horse finds some means of escape, like rearing or spinning, or very rapid reversing.
From this situation, the warning signal of "dodgy place - scary bikes!" also comes to mean "dodgy place - rider loses plot!". Each time the rider escalates, the equation becomes a self-fulfilling prophecy and the avoidance behaviour, napping, starts earlier and earlier; to pre-empt the bikes and the scary rider transformation, which of course begins to happen sooner.
Let's turn this scenario on its head. Horses learn all those warning signals through very simple, but very deeply entrenched associative learning - it's not even conscious! Just like Pavlov's dogs learned a buzzer came before food, horses notice what happens BEFORE what happens. happens. Horses notice sequences and patterns in time and space. It's a very useful adaptation and skill when you are a prey animal. Take your list from earlier and add to it. Beside each fear, write down all its possible warning signals, from your horse's point of view. Rank those warning signals from least to most scary. To help you, think about how your horse reacts to each, and how strongly.
Now we are going to discuss how we are going to desensitise AND counter condition your horse to them. Desensitisation is all about helping your horse to be less sensitive to each of these stimuli and sensations. This is achieved from a platform of a secure and satisfying life - so be sure to make sure your horse in general is living a good life that he can derive a lot of pleasure and satisfaction from. With this in place we gradually and gently reintroduce the horse to faded down versions of that which he fears. In such a way that he isn't scared or put off from munching through a hay net, or disturbed from the natural rhythm of his movement along or your gently applied aids when handling or riding. When he reacts calmly we can pair the situation with something your horse finds pleasurable: a good scratch, a small handful of pony cubes etc.
Since your horse will likely want to feel more in control of the situation we can run the desensitisation in cycles. A clear beginning, when the horse is calm and responsive to you. Exposure, but not too provocative that he can no longer listen to you, and while he is still able to cooperate with you calmly enough - make it end. He can be enjoying his reward while it's ending, or straight after its end. Whichever is most practical.
Back with those bikes! Begin in the arena, or other space next to a track, lane or road. When your horse is settled into being ridden, signal a helper on a bike to say hi and cruise slowly by. This is number 1, the warning signal. It's also number 2 - a predictable duration - the bike appears and goes on its way. Then for number 3: as they leave, reward your horse with a great scratch or a handful of food or a go of his lick. Ride around again, and when he's settled, repeat. Provided you set it up well so that your horse didn't over react, the bike will have left while your horse was able to remain lightly on your aids - a good way for you and for your horse to "make the bike leave" - yes ok, it was going anyway, but now your horse has reacted well and in a way you would like them to repeat again.
Your next steps are to repeat the ride-bys - aim for five in a row at the same level of challenge, and then make the challenge a bit trickier. Your helper riders faster, or nearer - but not both! Nearer might be you riding closer to the their line of travel rather than them riding closer to you. Faster can involve gear changes - which make a noise - so practice these at a distance before coming closer! You can add more helpers on bikes if possible, and you can find places more frequented by cyclists where you might be able to practice safely such as a road side field, or a good wide verge or bridleway.