Physics of the Senses 101 - Visual Perception or Sight

Foreword

Human beings are provided with a variety of senses that help them navigate the world around them, including five basic ones: sight, hearing, touch, smell, and taste. The organs associated with each of the latter report on certain sensations to the brain, which then translates them into understandable information, via a complex, yet fascinating process. Bright colours, a loud thud, an acute pain, a familiar flavour on the tongue or a sweet smell that tickles the nose – all these stimuli are put together into one big picture for us to identify our surroundings. However, while these systems are remarkably sophisticated ones in humans, some animals have super sensors. Felines are well-known for their nocturnal vision, elephants have the most powerful nose of the animal world, while bats rely on sound waves to hunt. Magnetoreception – the ability to detect the Earth’s magnetic field, is even considered a sixth sense that birds, along with certain mammals, reptiles, and fish, are gifted with.

The Physics of the Senses 101 series offers to explore the physical processes that make up each sense, including the so-called sixth sense, and to explain the extent to which they grant certain species 'super-capacities'.

1. Physics of the Senses 101: Visual Perception or Sight

2. Physics of the Senses 101: Auditory Perception or Hearing

3. Physics of the Senses 101: Haptic Perception or Touch

4. Physics of the Senses 101: Olfaction or Smell

5. Physics of the Senses 101: Gustatory Perception or Taste

6. Physics of the Senses 101: Magnetoreception or a Sense without a Receptor

Physics of the Senses 101: Visual Perception or Sight

Although recent research by the University of York demonstrated that there is no universal hierarchy of senses (Majid et al., 2018), vision is often considered as the most precious modality, at least in contemporary Western culture (Hutmacher, 2019). In an investigation on the dominance of vision in research by the University of Regensburg (Germany)'s Department of Psychology, 75% of participants to a survey indeed stated being most scared of losing sight over hearing, or even touch (Hutmacher, 2019, p.2). Bendong (2015) defines visual perception as ‘the ability to interpret the surrounding environment by processing information that is contained in visible light’ (p.1). In charge of this process are the highly specialised organ systems of the eye, while ‘the study for lights has been developed into an important branch of physics – optics’ (Bendong, 2015, p.2). Further, Hutmacher explains that, for debated reasons, 'the processing of visual information seems to dominate the processing of information from other modalities' (Hutmacher, 2019, p.3). This article will therefore start by describing the various physiological components involved in the important sense commonly referred to as sight, then explore the incredible abilities, such as near-nocturnal vision (Long et al., 2010) or even yaw gaze stabilisation (Daly et al., 2018), that cats, barn owls, and mantis shrimps are equipped with.