One of the most impressive (and sometimes frustrating) parts of teaching psychology is that, as a science, it is a subject constantly in a state of change. What we believe and assume to be true one day can (and often does) turn out to be not true the next. I would argue this is GOOD, because with each corrected error we get closer to the truth! Or...what we think is the truth.
I've recently been alerted by fellow bloggers of two very popular theories in psychology that are now under scrutiny. First, the folks at Neurotopia have provided an excellent background and critique of the Serotonin Theory of Depression in "Serotonin Theory (and why it's probably wrong)". Students in my classes will be talking about this theory within the next few weeks. Basically, it's the idea that depression may be caused by a lack of the neurotransmitter serotonin. The above article suggests that the picture on this is hardly clear.
Second, Michael Britt's most recent post on The PsychFiles concerns "The Learning Styles Myth: An Interview with Daniel Willingham." The interviewee, Daniel Willingham, calls into question the notion of "learning styles," a popular idea within educational psychology. In a nutshell, it claims that there are "visual learners", "kinesthetic learners", etc. and is closely related to Howard Gardener's ideas of Mulitple Intelligences. Willingham is not convinced. Maybe you shouldn't be either. Listen to the podcast and see what you think.
Perhaps either or both of these theories will go the way of Structuralism? Yeah, remember THAT term from Chapter 1?