Some actors are born right-brain dominated. These are inclined to imagination, emotion and complexity. They are often called the "emotional" types.
Some actors are born left-brain dominated. They are inclined to analysis, logic and solutions. They are often called the "technical" types.
Whichever type you inclined to, right or left, poetic or mathematical, logical or emotional, spontaneous or predictable, human beings--which include actors--have both lobes of the brain, right and left operating simultaneously. One may dominate, but both are in constant synergistic interchange and feedback.
If you are left-brain dominated, you will probably analyze the script plot-wise first: seeking-out the overall theme, the various conflicts, the character objectives. Only when you are comfortable there, you (generally secondarily) start to analyze character. In rehearsal, you will tend to "choose" and "set" character aspects. You will try to duplicate your choices in performance; and directors will tend to tell you to "loosen up," let the performance "just happen," be "more spontaneous" and "improvisatory."
Film editors will love you left-brain actors, because your performance tends to be consistent, thereby enabling the editor to cut in and out of the various takes whenever he or she wants. Such left-brain actors create little performance "matching" problems.
On the other hand, if you are right-brain dominated, you will tend to see the script character-wise first. "Feelings" and intuitions (about the character and the dialogue) will predominate plot considerations...if you see them. Your emotions will overwhelm you even in the reading. In rehearsal right-brain actors will tend to be unpredictable, eager for emotions to erupt performance. Directors will tell such actors "find the beats in the scene, the structure," try to be more "consistent, say the words as they were written," instead of "changing them all the time," which spontaneous right-brain actors too-often have a tendency to do.
Editors tend to hate right-brain actors. They tear their hair out while reluctantly admiring the actor's emotional performance: "Can't such actors be emotionally brilliant while maintaining performance (dialogue, blocking and prop) consistency?"
However...both type of actors--left-dominated and right-dominated--are acceptable as candidates for performance brilliance!
Neither type should over-praise (or curse) themselves for their strengths or their weaknesses of their approaches. Rather, they should begin their actor's process by first breaking down a role according to their logical or emotional tendencies...left-brain start with plot and early character-logic, right brain with feelings and 'honest emotion.' THEN, AS THEY REHEARSE, they should seek to refine their approaches (whether logical or emotional) according to their non-dominant brain-types; that is, each actor seek to balance their subsequent performances with some of the benefits that naturally accrue to their opposite brain-types.
To wit: A logical, consistent, technical approach to a performance should leave room for the spontaneity of performance to occur; surprised by their own sudden reaction to a look or gesture or emotion that was unexpected. After all, nothing is so fixed in life that the unexpected cannot happen.
Like a smart tourist, the good logical technical actor plans their performance trip rationally, define their itinerary in detail, but always leave room for the unexpectedly wondrous to occur...and to be enjoyed. Safety allows the occasional the dangerous (i.e., spontaneous unplanned moment) to be experienced; the structure-needing actor can always get "back on schedule/bullet point" when the unexpectedly wonderful occurrence plays itself out.
On the other hand, an emotional, spontaneous, free approach to a performance, can also seek organization, without necessarily leading to a dead performance. Discipline and structure can benefit rather than inhibit the generation of emotion. Beware of too much freedom---license---panic. For the spontaneous-inclined tourist, it often results that not knowing where you're going, or how, or when, or what clothes to wear can lead to a disastrous trip...or an aborted trip because the tourist enroute gets overwhelmed with too many "choices" and "truths" and heads back home..."Cut!"
So, good actors, seek acting balance in all things. Don't lobotomize your acting approach by confining yourself to only one lobe of your brain AND CUTTING OUT THE OPERATION OF THE OTHER LOBE. Start the overall acting process with your strength, logical or emotional as it may be...but, in your follow-up rehearsal and performance (or training for that matter), allow the other brain-aspect of yourself to arise, filling out and compliment your overall performance.
Classical musicians, allow feeling and spontaneity to caress the written notes; jazz musicians, remember that the melodic line is there, always to be obeyed.