In this classroom lecture, the professor explains how the unconscious mind governs many physiological and perceptual processes that lie beyond conscious control. He demonstrates that simple voluntary actions (e.g., reciting the alphabet, opening a hand) are conscious, whereas autonomic responses such as salivation, heart‑rate acceleration, and blood‑pressure changes can be triggered only indirectly through imagination. By asking students to picture a lemon or a high‑rise balcony, he shows that imagined stimuli elicit real bodily reactions, illustrating the unconscious’s power to respond to sensory cues. The talk then shifts to visual and cognitive ambiguities: classic reversible‑figure staircases, size‑contrast circles, and ambiguous drawings (old man vs. young couple). The professor describes how the unconscious mind represses one interpretation while presenting another, a process he labels “repression,” which simplifies perception by selecting a single dominant meaning at a time. Throughout, he uses everyday examples—movies, emotional scenes, and classroom demonstrations—to make the abstract concept of unconscious processing concrete, emphasizing that the unconscious continuously shapes our feelings, decisions, and visual experience without our awareness.
Chapters
The conscious mind has often been described as just the tip of the iceberg, as this diagram sort of hints at. And now there are behaviors that you're capable of doing. For instance, if I ask you to say the ABCs or tell me where you live, you have no problem responding to that. Or physically, can you do this? Try this. Just open and close— "Close your hand." No problem at all. Now, cause yourself to salivate. It's different. You can't just do that. If I say, "Raise your blood pressure and speed up your heart," you have no way to do that. So these are behaviors of your unconscious that are not voluntary. But, as we demonstrated last time, if I tell you— and you can try this— imagine you have a lemon and that you cut it into quarters, and that you take a quarter of a lemon like that and— mm— sink your teeth into that juicy flesh of the lemon, let the sour lemon juice flow over your tongue. Can you feel the salivation? So you are actually able to cause your unconscious mind to respond in a certain way. Or the other one is imagine yourself standing on the top of a 50-story building, right at the edge, and looking over, and leaning way over, so you can see all the windows going down. Yeah? Your heartbeat speeds up a little bit, your stomach gets a little knot in it, your blood pressure goes up. Those of you with good imagination can feel that. Any one of us can feel it. In fact, when you go to a movie, you sit in the movie, and you feel bad for the— person on the screen who just lost her son in this automobile accident. I tell you, that's not a person up there. That's just light that's bouncing off the screen. It was actually a movie that was made 30 years ago, and they were just pretending. But you feel it. Or you feel Nicolas Cage as he's fighting the bad guys or whatever. Again, all that's happening is that your unconscious mind is being called forth to behave in certain ways because of the images that it's being shown. So, this is a little bit of a review, but it's worthwhile because it gives you a chance to experience your unconscious mind. It's a familiar illusion. The stairs, you see, you can think of the stairs, the white is the part that you stand on and you go down. Or you could stand on the black and go down. [Speaker:STUDENT] Or up. [Speaker:PROFESSOR] Yeah, or up. But you can see it flip from one to the other. How does that happen? First it's going down into the left and then it's going down to the right. But you see, the important thing is you can't see them both at the same time. You can't see them both at the same time. That's one of the actions of your unconscious mind. It represses the other one. So repression is a way that the unconscious mind keeps material out of your consciousness to make it easier for you to see and understand what's there. It makes a decision for you. And again, the central spot there, are those the same size or which one is bigger? Now, you know they're actually the same size, but they look bigger because your unconscious is comparing the dot with the ones around it. It makes a decision about the size and then presents you with the information. And again, are these lines straight, the horizontal lines, or are they crooked? They are completely straight, but your unconscious mind interprets them as being crooked. And read this out loud. [FOREIGN LANGUAGE] And now proofread it. [FOREIGN LANGUAGE] Right? Right? And so the first time you see it, again, your unconscious mind gets the meaning of it and gives you that. It doesn't really let you read it. This is going on all the time. And what do you see here? See the old man? Okay. Do you see the young couple? After a while, you begin to see the young couple. And again, it's very difficult to try and see them both at the same time. This is what the unconscious does. It suppresses one so that you can see the other.
