Time to stop visiting the psychic! In a new study published in the journal PLoS One, researchers prove that people can reliably sense when a change has occurred, even when they cannot see exactly what has changed. “There is a common belief that observers can experience changes directly with their mind, without needing to rely on the traditional physical senses such as vision, hearing, taste, smell, and touch to identify it. This alleged ability is sometimes referred to as a sixth sense or ESP,” Dr. Piers Howe from the Melbourne School of Psychological Sciences and lead researcher stated in a press release. “We were able to show that while observers could reliably sense changes that they could not visually identify, this ability was not due to extrasensory perception or a sixth sense.”
Most people have had the experience of noticing a change in a co-worker’s appearance without being able to identify the exact difference: Did Sarah change her hair or is she not wearing her usual hoop earrings today? A team of researchers decided to investigate exactly this phenomenon. For their study, the team designed four separate experiments to test participants' ability to see and identify change. In the first experiment, a computer program presented participants with paired photographs of the same woman. Although in some cases, the woman’s appearance would be different in the second photographs, in other cases it would not. With each pair, the first photograph was presented for 1.5 seconds followed by a one-second blank interval, and then the second photograph was shown. After this, participants were first asked whether a change had occurred in the woman’s appearance; when they indicated it had, they were then asked to identify the change by clicking on one item in a list of nine possible options, for instance “earrings” or “eyeglasses.” Following this first experiment, the researchers devised three other experiments in which they varied the subject within the paired photographs or used entirely other stimuli.
Out of 100 trials where a change had occurred, the participants were correct in stating this for 73 trials, and of these they were able to identify correctly what had changed in 60 trials. For 13 trials, then, participants correctly identified a change had occurred without being able to correctly identify what had changed.
“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,” the authors wrote in their study. Even though participants themselves may have said they "sensed" or “felt” a difference, results proved that an observer can reliably feel or sense when a change has occurred without being able to visually identify the change. Thus, an “extrasensory” mechanism is not necessary to explain this occurrence. Instead, the authors recall the work of another researcher who also explored this territory.
In a 2004 research paper published in Psychological Science, Dr. Ronald A. Rensick from the University of British Columbia, discussed two experiments that follow a similar path as the previously mentioned experiments. In his study, Rensick used paired photographs of real-world scenes. Observers viewed a sequence of displays alternating between an image of a scene, and the same image changed in some way, with “blanks” interspersed between these pairs. The blanks shown to observers were either gray or bright yellow, a kind of flash that created luminance.
“The results presented here show that at least 30 percent of observers can reliably sense a continual change — that is, have a conscious awareness of it without an accompanying visual experience,” Rensick wrote in his conclusion. “The subjective difference between sensing and seeing is mirrored in several behavioral differences, suggesting that these are two distinct modes of conscious visual perception.” Rensick names and then further explores this phenomenon. “Given that this mode of perception involves a conscious (or mental) experience without an accompanying visual experience, it might be called mindsight — in analogy with blindsight, which describes a lack of both mental and visual experience.”
Mindsight, he argues, is not based on picking up transient signals from the environment. Instead, Rensick posits that the process operates concurrently with seeing. In his set of experiments, then, the experience of an observer depended on whichever of these two processes detected the change in images first. Next, Rensick suggests that mindsight may be relatively slow in comparison to seeing. He also wonders if there may be large individual differences as to how these two independent processes of seeing and sensing are coordinated, with some people relying on one more than another; such an explanation would account for why mindsight is encountered in only some observers and not others. Finally, he suggests that at times people give a scene or an image their full visual attention and take pains to see, whereas in other instances, they simply give a matter their "non-attentional processes" and rely on mindsight to detect change or difference.
Howe PDL, Webb ME. Detecting Unidentified Changes. PLoS One. 2014.
Rensink RA. Visual Sensing Without Seeing. Psychological Science. 2004.