Reactive behavior is the ability to respond to internal and external incentives. Because we are daily overwhelmed with incentives of various kinds, we have - depending on type, time, place and priority - developed all kinds of reaction patterns and reaction mechanisms.
Response patterns provide recognisability and response mechanisms, but reduce the ability to spontaneously anticipate internal and external incentives. Many of our reaction patterns turn out to be an automatically internalized mirror pattern of parents and others. That feels safer. Because as long as we mirror the reaction patterns of parents and others, they can control the reaction patterns of us and others, as if it were the reaction patterns of themselves. So they can predict exactly how we and others will respond to this or that situation. So they can respond in a predictable way and that gives a divine narcissistic illusion of power and security. After all, the reactions all have been made ... in their image .... [Bible, Genesis 1:26] of their reaction pattern. Their similarity ... with the beastly ancestors from South-, Middle- and North Africa. Even if our response and/or that of others is unsafe, because it feels familiar. After all, they would have done it the same way.
Over the years, many of these reaction patterns have been cultivated and handed down from generation to generation. This has created a complex response mechanism that sets dictatorial requirements for the reactions and reaction patterns of conscious and spontaneous responders, dissenters and newcomers. Because oh woe to those who don't. Who don't respond according to the beastly cultivated reaction mechanisms of ancestors and others. Then you have the beastly stimuli and all those divine response mirrors to war dancing. They all group together to eradicate the non-reflective response patterns. Away you. That is why for billions of years we have reacted positively to one and negative to the other in a sort of similar way, and take that for granted as well. Even though that is not fair, even though it hinders our self-initiated responsiveness, even though it makes us one divinely beastly response mechanism.
In other words, cultural response patterns and mechanisms have major implications for the individual's ability to respond. The more influence parents and others have on our reaction patterns and mechanisms, the less we are free to decide for ourselves how we respond to in- and extrinsic stimuli, the less practice we develop in it, the more inadequately our responsiveness responds to our own ideas and conditions and all the better according to that of others.
Which means, as the lack of practice in intrinsically controlling our own response patterns and mechanisms increases, our self-initiated response capacity decreases.
With the consequence, little or no thinking about one's own ideas and conditions for reaction patterns and mechanisms and reflecting too much on those of others.
With the consequence, few reasons to be proactive - ie. with self-initiating responses - responding to unwanted reaction patterns and mechanisms. To the delight of all "divinely" beastly narcissists in the world of yesterday and today.