Summary: A new study measures individual differences in perceptual capacity. Findings suggest people have a consistent level of performance across different measures of perception.
Some people have superior powers of perception, showing greater ability to spot objects, even from brief computer screen presentations of just a fraction of a second or in busy visual environments, whether the objects appear inside or outside their focus of attention, according to a new UCL study describing an objective method that can be used to test for perceptual capacity.
The study, which was published in the Journal of Experimental Psychology: Human Perception and Performance, measures individual differences in perceptual capacity (the number of things a person can perceive and detect simultaneously), finding that people have a consistent level of performance across different measures of perception, such that, for example, a person that is found better at detecting the change of a single object in a cluttered image will also be better at tracking objects moving at random, spotting an unattended item, and instantly identifying the number of objects presented for less than a quarter of a second.
It is the first study to identify perceptual capacity as a distinct, measurable ability that varies between individuals. It is, as the study shows, separate from general cognitive faculties, and cannot be explained by working memory capacity (the amount of information people can actively maintain in their short term memory as they process incoming information).
The study further demonstrates that a person’s perceptual capacity can be predicted from objective measures of their performance in the computerised tests administered. For example, a simple test of their ability to instantly detect how many items are briefly presented to them. The researchers analysed performance on this task and derived from it the ‘breakpoint’ at which each person could no longer instantly detect accurately the number of items presented (a process called ‘subitizing’). They found that from this it is possible to predict a person’s overall perceptual capacity as then manifested in all other tests. Similarly a short battery composed of all computerized measures could be used as a robust new test. The researchers see their work as providing a scientific basis for screening tests to recruit for safety-critical professions such as pilots or airport security personnel.
Some of the studies reported took place at the Science Museum in London where members of the public took their tests. For example, Museum visitors were given the ‘subitizing’ test. The same people were also took part in a change detection task. They were presented with pictures of busy scenes (for example London streets) arranged in pairs of images identical to each other, except for one change. The task was to spot the change. The results showed that change detection ability could be predicted from the ‘subitizing’ test. “We identified a novel trait that is different from working memory, general intelligence or motivational factors. It can be very important for people in professions that require a high degree of perception and detection abilities in high load environments such as pilots in the cockpit, air traffic controls and other operators (e.g. in security) that have to monitor multiple screens” said the study’s lead author, Professor Nilli Lavie.”
About this neuroscience research article
Source:UCL Publisher: Organized by NeuroscienceNews.com. Image Source: NeuroscienceNews.com image is adapted from the UCL news release. Original Research:Abstract for “Establishing individual differences in perceptual capacity” by Eayrs, Joshua and Lavie, Nilli in Journal of Experimental Psychology: Human Perception and Performance. Published April 23 2018. doi:10.1037/2Fxhp0000530
[cbtabs][cbtab title=”MLA”]UCL “People Differ in Their Power of Perception.” NeuroscienceNews. NeuroscienceNews, 25 April 2018. <https://neurosciencenews.com/power-perception-8876/>.[/cbtab][cbtab title=”APA”]UCL (2018, April 25). People Differ in Their Power of Perception. NeuroscienceNews. Retrieved April 25, 2018 from https://neurosciencenews.com/power-perception-8876/[/cbtab][cbtab title=”Chicago”]UCL “People Differ in Their Power of Perception.” https://neurosciencenews.com/power-perception-8876/ (accessed April 25, 2018).[/cbtab][/cbtabs]
Establishing individual differences in perceptual capacity
Limited capacity for visual perception results in various “inattentional blindness” phenomena across a wide variety of manipulations that load perception. Here, we propose that these phenomena are mediated by an underlying generalized capacity for visual perception, which also underlies subitizing: the ability to enumerate a limited number of items in parallel from a brief exposure. We tested this proposal by examining whether individual differences reveal common intraindividual variance between measures of visual perception as well as of subitizing capacity. Visual perception was measured in change blindness (Rensink, O’Regan, & Clark, 1997), load-induced blindness (Macdonald & Lavie, 2008), and multiple object tracking tasks. Subitizing capacity was measured as the number of items that could be reported in parallel in an enumeration task. Perceptual capacity as indexed by subitizing was consistently a unique predictor of performance in change blindness, load-induced blindness, and motion tracking beyond any general factors that apply to both subitizing and estimation of larger set sizes. Moreover, when measures of working memory were included, factor analysis indicated two orthogonal factors: perceptual and working memory. Overall, the results support the hypothesis of a generalized capacity for visual perception, and establish subitizing capacity as a predictor of individual susceptibility to inattentional blindness under load.