Whether it's a sudden dash across the garage or silhouette in a backyard web, spiders evoke fear in many people. But researchers don't have a clear picture of why, exactly, this phobia is so common. An interdisciplinary team at the University of Nebraska–Lincoln is using state-of-the-art eye-tracking technology to pinpoint the physical characteristics of spiders that may contribute to the unease.
Emma Brase, a graduate student in psychology, was lead author on a recent Frontiers in Arachnid Science publication in which Husker researchers described results of a study aimed at understanding how people allocate their attention when looking at images of spiders and other arthropods, the hard-shelled group of animals to which arachnids belong. Using various photographs, both single images and pairs, the team mapped participants' eye movements to the millisecond as they viewed the photos, using multiple eye-tracking metrics to identify patterns.
This data, paired with information from surveys measuring phobia and attitudes about spiders, is providing the team a window into how people look at spiders — and how that pattern of attention shapes perceptions. The big-picture goal is to better understand the mechanisms underlying arachnophobia, paving the way for more effective mental health treatments. The research may also improve peoples' relationships with nature, particularly spiders, which play vital ecological roles.
"If I know what turns people off about arachnids, that can help me figure out how to avoid those things and focus on things that might turn people on about arachnids," said principal investigator Eileen Hebets, George Holmes Professor of biological sciences.
She said this attitude shift could bolster support for conservation policies, which are critical to maintaining spiders' roles in biodiversity, pest control, crop protection and more.
For the study, 118 undergraduate students viewed spider images and pairs pictured in their natural environment. Husker psychologist Mike Dodd measured the participants' eye movements across four domains using an SR Research EyeLink 1000, a tool that measures the position of the eye every millisecond. Together, these metrics — dwell time, first run dwell time, first fixation time and run count — provided evidence of how viewers directed their attention.
As expected, when faced with a spider and non-spider image, participants generally avoided the former. Counterintuitively, though, when the choice was between a spider and a spider with an obvious "spider cue" — a web, eggs or fangs, for example — more attention was devoted to the spider-specific features. The exception was hairy spiders, which were avoided in favor of non-hairy spiders.
The researchers have a few theories about this unexpected finding. One is that an image with more features, like eggs or a web, will draw attention simply because it is more interesting visually. Another possibility focuses on spiders' movement patterns.
"When I talk to people about their fear of spiders, one of the first things they mention is how fast they are and how unpredictably they move," Hebets said. "It makes a lot of sense to me that people might be less afraid of a spider in a web than one on the ground, because of the predictability."
Anthropomorphism may also be a factor. Dodd speculated that certain contexts, like a web as a "home" and a jumping spider with two distinctive, large eyes, make spiders seem more human-like.
Hebets said the study is unique for exploring phobias from a biological perspective rather than a psychological lens. This knowledge could be particularly helpful to people for whom phobias are especially detrimental, such as military personnel deployed in locations with unfamiliar animals.
"I think it's really important in a lot of different venues to understand how humans react negatively to things they might encounter in the world, and how we can prepare them or help people mitigate these experiences," she said.
The project, funded by a University of Nebraska Collaboration Initiative grant, reflects Hebets' success in facilitating cross-disciplinary research around arthropods at UNL. That mission gained additional momentum with the 2024 launch of the Community for Arthropod Research, Education and Materials Innovation , or CAREMI, a nationally unique research group that unites researchers of all stripes — engineers, biologists, psychologists, social scientists and more — in conducting arthropod-related research.
Later this year, CAREMI, which was initially supported by a Grand Challenges Planning Grant, will sponsor an exhibition at the Great Plains Art Museum featuring the work of the University of Wisconsin-Madison's Jennifer Angus, who creates art installations using arthropods. Hebets and Dodds aim to collect additional eye-tracking data on how people interact visually with that art.
Hebets and Dodd agree that their collaboration, and CAREMI more broadly, are distinctive for their highly interdisciplinary nature. The eye-tracking project afforded Brase and other graduate students a cross-disciplinary training experience that is rare at most universities. For Nebraska faculty, working outside disciplinary boundaries amplifies the university's innovation potential.
"We are not in a place where we have an infinite number of experts on every topic," Dodd said. "The way, then, to expand your science and ask new, cutting-edge questions is to do that in collaboration with people who can bring different skills and measures and abilities to your research."
The Husker team also includes Kevin Smith, Leland J. and Dorothy H. Olson Professor of political science; Heather Akin, associate professor of agricultural leadership, education and communication; Brandi Pessman and Laura Segura Hernández, former graduate students in biological sciences; and Harley Boutard, undergraduate student in psychology.
Writer: Tiffany Lee, Office of Research and Innovation
