Therapist-free therapy: Cognitive-bias modification via computer sessions

The studies referenced in the article suggest a handful of short sessions, with a computer program designed to combat things like anxiety or addiction, can have lasting psychological effect.

While unremarked about in the article, I think this suggests the question: How about all our much-longer interactions – games, browsing, communication – with computers? It seems unavoidable that even without conscious design, they too could have lingering effects.

How much does repeated interaction with Farmville (or Twitter or Reddit) alter later behavior?