In Simons and Levin's experiment, what did the woman fail to notice during her conversation?

In Simons and Levin's experiment, the woman failed to notice that the person she was talking to changed. This is a classic demonstration of change blindness, where individuals do not notice significant changes in their visual field due to unexpected shifts in their environment. In the context of the experiment, while engaged in a conversation, the woman is interrupted, and during that moment, the person she was speaking with is replaced by another individual, yet she remains unaware of this change. This highlights how our attention can be focused to the point where we overlook substantial alterations in our surroundings, providing insight into the limits of our awareness and the mechanisms of attention in social interactions.