phobia
The word 'fobia' in Spanish translates to 'phobia' in English. A 'phobia' is an extreme or irrational fear of or aversion to something. This can include a wide variety of things such as specific objects, animals, situations or environments. Typically, a person who has a phobia will go to great lengths to avoid the thing they fear, and if they cannot, may experience significant distress and anxiety.
Do you study the psychology of phobias?
Here, the speaker is asking if the person they're speaking to studies the psychology behind phobias. '¿Estudia' is the formal way to ask 'Do you study?', and 'la psicología de las fobias' means 'the psychology of phobias'.
She has a phobia of enclosed spaces.
This sentence is about a common fear in people, claustrophobia. The term 'espacios cerrados' means 'enclosed spaces', and is a way to describe situations or places that might make a person with this fear feel trapped or confined.
My phobia of spiders began in childhood.
In this sentence, the speaker is indicating when their fear of spiders started. 'Arañas' is the Spanish word for spiders, 'comenzó' is past tense for began, and 'en la infancia' means 'in childhood'.