Owing to the fact that a person's hand size appears to stay constant, many people use it as a natural ruler, a new study finds.
The study was conducted by researchers from the Association for Psychological Science.
"These findings suggest that our bodies are used as perceptual metrics, meaning that we are more likely to attribute changes in the perceived size of the hand to changes in the world - instead of thinking that our hand has become bigger, we're more likely to think that the world around the hand has become smaller instead," explained psychological scientist and lead researcher Sally Linkenauger of Lancaster University, in a press statement.
Generally, we use the information we see with our eyes and transform it to units that are relevant to our everyday lives. This is usually done so that we can size up the world around us. The study was conducted across five experiments. Participants were made to view their dominant hand, as well as various other items, under 18 percent magnification. The researchers noted that the participants consistently estimated their dominant hand to be significantly less magnified than the other items, which included their non-dominant hand, their foot, and an experimenter's hand and foot, and a pen.
"In most cases, individuals knew that their dominant hand was under the same degree of magnification as another's hands, feet, and objects, yet they persisted to report that what they experience was a smaller degree of magnification for their dominant hand," said Linkenauger. "Individuals typically like to be consistent and 'right,' but this effect seemed to override those affectations."
The findings hint at human-computer interfaces and researchers plan to investigate whether hand size constancy also applies to virtual environments in which individuals have an animated virtual hand.
Findings of the current study were published online in Psychological Science, a journal of the Association for Psychological Science.
