For children this is an easy game to play and for many, one which engages them for a long time, way beyond our ability to find the game fun, or to be able to come up with new ideas for them to 'find'.
As adults, we forget just how plastic a child's brain is and we also forget how simply they think.
I am not sure if you are aware, but when a child reads, they will happily skip over words they do not know and use the remaining words in the sentence to make sense of that unfamiliar word. Sometimes they get it right and sometimes they get it wrong, but over a period of time and more exposure to the word, they get the meaning correct, they win the game of 'hotter and colder'.
This happens with verbal and non-verbal reasoning, they can get cope with being wrong, they can cope with not getting the whole answer straight away, they can cope with being hotter or colder, but as they do it more and as they make their minds up what it really means, they find they 'get it' most of the time.
No doubt you have seen this with the second set of tests they have done by the increase in their marks. Many have increased their original marks by between 5% and 35%, very few have decreased and if they have, they realise they are 'getting colder' and their brains must try a different tack.
I have had many parents saying they have found the questions hard, and yes, parents will, because we as adults no longer have that plasticity to manipulate in this way. If you looked at our verbal and non-verbal questions (the ones used as diagnostic tests by some employers), you will note some types are still there but most have changed. We change, and as we get older and funnel our ways of thinking into what has worked for us in our 'hotter/colder' game, we are not able to see the alternatives any more, we have run out of option finding, we no longer play that game.
That is a bit dramatic, let us say we no longer have that level of plasticity and therefore have only limited levels of the game left to us.
We find the questions hard and in so doing show our children that its OK to be wrong, its OK not to get everything right and by asking the right people for help is also OK.
Children believe adults are 'gods' who can do no wrong and know everything. Let me say at this point, we are not Spock.
Remember, they think we are Gods until they get to their mid teens, its only when they realise we are not and are human that things start to..how shall I put it...change.