>>> 
>>> 2) Al zo lang ik Lolita ken reageert ze apart als ze snoep
>>> krijgt, zowel als beloning als voor de verwennerij. Ze gaat de 

> trekken?
 > 
 > Bedankt,
 > Nathalie
Het in zichzelf keren  deed  me  wat  denken  aan Apache  van  Marianne. Hoewel die juist enorm veranderde van clikkertraining
Ik  wilde  wat  meer  inzicht  over  dit  gedrag, daarom heb  ik  dit beschreven op  een  ander forum.
Ook  hier  komt  men  bij  de  beschrijving  van 
Parelli.
Het  is een uitgebreid  antwoord en  volgt hieronder.
Linda 
Parelli, in the Horse Behavior and Liberty Training home study materials, describes this very behavior in her own horse Allure whenever he gets a cookie (although now he's getting better, and it's becoming less frequent). She uses the term "going catatonic" because the horse appears to withdraw, shut down, and go into his "happy place" where he can hide and nothing can harm him for a while. 
She describes Allure as usually a very confident horse who becomes very unconfident in new learning situations - possibly because the offered learning behaviors were "trained" out of him as a young, curious, mouthy horse who was gelded late. In their experience they see horses like this can go from confident, even dominant, to very unconfident (right brained) and back again within a matter of minutes. And I think we've all seen this in some horses. 
They propose the scale for such behaviors progresses something like this: confident to unconfident to right brained extrovert to right brain introvert, to then right brained catatonic. So the 
Parelli's consider introversion and catatonic to be forms of extreme right brained behaviors, which are often misread because the horse looks deceptively calm. 
When the horse retreats into this behavior she suggests that one slow down and create rapport by matching and mirroring the horse's behavior and state of mind. Be soft and respectful of his need, until he/she comes out of it and breaths normally. Or, if you recognize it early enough you may be able to interrupt the pattern in some way.
It's taken Allure quite a long time to come out of this pattern of behavior in his new learning environment. As per 
Parelli explanation, apparently it's a fairly common response with some horses when they unconfident, uncomfortable, or insecure in some situation or new learning experience. They interpret the withdrawal as a reaction to stress, and the cookie or treat as triggering endorphins that helps him cope with it. It's funny that she has observed that sometimes another cookie will help bring Allure out of this trance.
I thought all of this was very interesting, and it's given me something to think about and keep in mind as I look for the tiniest of signs that announce whatever state of mind is showing up in the horses I interact with around the barn. Anyhow, it's something to consider.
Sincerely,