Londo: Sometimes a person sees what they want to see...
You are right. The brain plays a critical role in seeing. Seeing is not just a physical reaction by the eyes - it is also the brain working to interpret what the eyes see. And sometimes, a person can see and react to what they don't even know is there. This is supported by science. It is not something just made up by crazy people.
I posted the following information on the other 'image thread' that discussed the 'disfellowshipping image' but I will repost it for anybody who missed it:
From pg. 100 of Handbook on the Economics of Discrimination by William M. Rodgers:
Devine (1989) conducted a clever experiment to test whether very subtle factors could influence categorizations. One hundred and twenty-nine students enrolled in an introductory psychology course at Ohio State University participated in the experiment for course credit. Participants took the Modern Racism Scale to determine their prejudice level. Participants were then shown Subliminal images) appearing on a computer screen for less than 30 milliseconds) of words associated with the social category ‘black’ (for example, black, poor, ghetto and negroes) using the stimuli priming method developed by Bargh and Pietromonaco (1982). Subjects were told that the experimenter was interested in how people form impressions. They were asked to read the famous ‘Donald paragraph’ which is a 12-sentence paragraph that has Donald engaging in ambiguously hostile behaviors like withholding rent until an apartment is painted or demanding money back at a retail store. The results were startling: participants who had been given the subliminal images rated Donald as significantly more hostile, and this was true for all prejudice levels. This experiment demonstrates the power of implicit associations and how such associations have been measured.
Another study that measures brain activity in response to subliminal images:
How the Brain Translates Money into Force: A Neuroimaging Study of Subliminal Motivation
Abstract:
Unconscious motivation in humans is often inferred but rarely demonstrated empirically. We imaged motivational processes, implemented in a paradigm that varied the amount and reportability of monetary rewards for which subjects exerted physical effort. We show that, even when subjects cannot report how much money is at stake, they nevertheless deploy more force for higher amounts. Such a motivational effect is underpinned by engagement of a specific basal forebrain region. Our findings thus reveal this region as a key node in brain circuitry that enables expected rewards to energize behavior, without the need for the subjects`awareness.
There are other studies besides the two examples I just posted that support the theory that subliminal images can effect behavior.