[user104658]

She's a pop-psychologist, just makes half of it up as she goes along based on her own feelings and some vague observations of body language, but even those are clumsy. I have no idea where they got her from. You're right she said "Jackie would rather choose Callum than Dexter" purely because SHE would - Jackie's own interactions with the two have never suggested that at all. She doesn't trust Dexter, especially with her daughter's feelings, but she's much warmer towards him than towards Callum who she quite clearly actively dislikes. Any half-decent psychologist should have been able to see that. I only have an undergraduate degree in Psychology, and have never actually worked in a related job, and find it painfully obvious.

I have only two explanations;

1) She is just really rubbish at her job, and isn't good at reading people OR

the more likely 2) ... she doesn't actually bother to watch the show properly and get to know the housemates, and makes basic snap judgements based on very little.