Great question! It took me a very long time to learn what I/O psychology was (I learned about it between 3rd and 4th year of my undergraduate) so you're very ahead of where I was.
You asked: What is I/O Psych?
The field of industrial and organizational psychology applies the science of human thinking and behaviour to the workplace. All organizations, from government to non-profit to for-profit companies are targets of research in I/O psychology. Some questions the field of I/O psych might ask include:
- Why do people leave their jobs? Is it because of their manager? Their pay? Stress on the job? All of these?
- Are interviews helpful when hiring? Are they fair? Are they the best way of hiring people?
- How can we make sure teams work well together and don't end up hating each other? (this is my favourite and the focus of my graduate school research)
and lots more.
You then asked: What do I/O Psychologists do?
We generally work in one of three different areas: academics (including teaching and research), consulting companies, or inside organizations. Academics spend most of their time creating new research and teaching/mentoring students. Consultants help other companies understand I/O psychology and how it can help their organization. People working inside organizations usually implement new fixes to make the company a better place to work.
Here is a list of job titles than someone might have if they studied I/O Psychology:
That website, www.siop.org, is really helpful for learning about I/O psych as it's the international organization that brings us I/O folks together.
Happy to answer any other questions about this topic!