New research demonstrates that humans can subconsciously detect and assimilate changes in visual stimuli without knowing where that information came from, or what exactly changed. The study suggests that this phenomenon of "knowing without knowing" can often be mistaken for psychic ability or supernatural intuition.
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A team of researchers at the University of Melbourne led by Piers Howe presented test subjects with pairs of color photographs of the same person's face. In some cases the two photographs were identical.
In others there were minor but significant differences (for example in one photo the person might be wearing glasses, or have a different hairstyle). Each photograph was seen for one and a half seconds, with a one-second break between the images. The subjects were then asked to determine whether or not a change had occurred-and if it had, to correctly identify the change from a list of possible options.
The researchers conclude, "In this study we have provided direct behavioural evidence that observers can regularly detect when a change has occurred without necessarily being able to identify what has changed.... We found that this ability to detect unidentified changes is not unique to images containing faces." Though the general phenomena (known as change blindness) has been known for decades, according to Dr. Howe this is the first scientific study to demonstrate that that people can reliably sense changes that they cannot visually identify.
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Illusions of ESP Humans pick up subconscious visual cues from their environment and assimilate it into their knowledge without realizing it. Say, for example, in a test a subject momentarily meets a person, exchanges a few words, and is afterward asked to give as much information as possible about the person they met for less than a minute. Without saying a word, we absorb enormous amounts of information about people; how a man dresses gives clues about his lifestyle and economic class; how a woman speaks can provide key information about her education, upbringing, and even nationality; their general physique gives clues about health, level of fitness, and even career (a typical construction worker's body will look different from a ballet dancer's, or a football player's).
None of this information is completely accurate, of course; they are what psychologists call heuristics, or general rules of thumb that are likely to be correct based upon common sense, logic, and probability.
In a nutshell, you gather information, or notice that something has changed, but you don't know how or why you know it. Since you're not aware of noticing the change, the information seems to come from outside yourself, perhaps in the form of intuition or even psychic information.
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Dr. Howe notes that from the perspective of a person who "knows without knowing" (that is, know something but doesn't know how or why she knows it), "the experience was similar to that of a sixth sense, in that they could sense information that they believed that they could not see. We were able to show how this processed worked and debunk the claim that this was due a quasi-magical ability such as the sixth sense. The point is that people can sometimes get the strong impression that they can sense changes that they cannot see. What we showed was that while this sensing ability is indeed real, it has nothing to do with a sixth sense, and can be explained in terms of known visual processes."
The study, "Detecting Unidentified Changes," was published January 13 in the open-access online journal PLoS-ONE. It does not (and was not designed to) conclusively debunk alleged psychic powers, but instead provides a plausible, proven mechanism by which people can sense changes they are not aware of perceiving.