In Food Taste Better When You Are Hungry, I wrote about a paper that examined how our affective state influences sensory perception. The experience illustrates the general fact that emotions influences how we see the world.
A recent paper from Current Biology explores how fear alters spatial perception (Vagnoni). When we see an object heading toward us – a ball for example – the rate of change in our visual field allows us to gauge the distance and time the object will make contact.
In this study, looming objects (ie. expanding in size) were presenting on a screen and the subjects were directed to estimate when it was expected to collide with them. When presented with a snake or spider the subjects assumed it was closer and underestimated collision times when compared to images of a rabbit or butterfly. In addition, the study found that the level of fear was proportional to how much the subject tended to underestimate the collision time.
Other studies have found that fear of spiders can make them seem 3 times as large, both at the moment and in the recollection (Vasey); people with fear of heights consistently overestimate altitudes (Stefanucci 2009) and judge slopes to be steeper (Stefanucci 2008).
In short, fear makes everything seem worse than it actually is.
Because fear is such a basic response, I think it is reasonable to assume other non-human animals (at least mammals) experience the same perceptual distortion when they are afraid. It’s a vicious circle; fear creates a perception bias making things scarier which plays a role in the maintenance and possibly the heightening fear which in turn increases perceptual distortion.
So if you have a fearful remember that in her mind that approaching dog (bike, car, person, etc) is bigger and closer than you could possibly imagine and it’s about to collide with her.
Vagnoni E, Lourenco SF, & Longo MR (2012). Threat modulates perception of looming visual stimuli. Current biology : CB, 22 (19) PMID: 23058796
Vasey MW, Vilensky MR, Heath JH, Harbaugh CN, Buffington AG, & Fazio RH. (2012) It was as big as my head, I swear! Biased spider size estimation in spider phobia. Journal of anxiety disorders, 26(1), 20-4. PMID: 21906909
Stefanucci JK, & Proffitt DR. (2009) The roles of altitude and fear in the perception of height. Journal of experimental psychology. Human perception and performance, 35(2), 424-38. PMID: 19331498
Stefanucci, JK. (2008) Skating down a steeper slope: Fear influences the perception of geographical slant. Perception, 37(2), 321-323. DOI: 10.1068/p5796