As the presentation says right at the beginning, "Optimism" in this context has a specific meaning defined by Dr. Martin Seligman for his work. It refers to the

As the presentation says right at the beginning, "Optimism" in this context has a specific meaning defined by Dr. Martin Seligman for his work. It refers to the way people explain good and bad things that have happened to them in the past. It does not speak to people's expectations for how things will happen in the future. In technical contexts, practitioners often use words in ways that do not match the common parlance.