Biology of sensory perception
6 Other Sensory Signals
Sensory cues are signals that show what is happening inside or outside of the body. External sensory cues come from the environment, such as light, sound, or smell. Internal cues come from within the body, such as taste. These cues provide information about the surroundings and the body’s condition.
VISION (sight)
The first sensory contact with food is usually through the eyes. Along with orthonasal olfaction, visual cues are involved in the anticipation of food intake and help guide eating behaviour. Sight is an example of an external sensory cue, leading to an expectation about a food’s taste.1
For example, the colour of an apple tells you what kind of apple it is, and what kind of taste to expect based on earlier experiences; a green apple usually tastes more sour than a red apple, which in its turn tastes sweeter. Also, the saturation of a colour gives you information; a more intense red drink suggests it is sweeter than a less intense red drink.
TACTILE SENSATIONS (TOUCH)
The somatosensory system includes nerves under the skin that send information to the brain and spinal cord, leading to tactile sensations like touch, pain, pressure, temperature, and body position.
In the mouth, different receptors sense the touch, texture, consistency and temperature of foods. The tongue detects the shape, size, and texture of foods during eating. Texture and mouthfeel are important sensory characteristics of food items. Texture can be defined as the perceived structure[1].
AUDITION (sound)
Auditory sensory cues can be both external and internal.
External auditory sensory cues can be explained as ambient sound, for example, the noise of trains, announcements, and other passengers when drinking a cup of coffee during a morning commute. External auditory cues can also influence expectations of food. Think of the sizzling sound during grilling, or the fizz of sparkling soda.
The sound that food makes during biting, chewing, and swallowing is called higher food salience. These are internal auditory sensory cues that give you information about the food you are eating. A crisp fresh biscuit leads to a quite distinct experience than a stale biscuit from a package that has been open for a few days, even if the taste is the same.
Together with tactile sensations audition gives you information about the texture of a food. A higher food sound salience — more food sounds during biting, chewing and swallowing — has been associated with a lower food intake[2].
- Forde, C. G., & de Graaf, K. (2022). Influence of sensory properties in moderating eating behaviors and food intake. Frontiers in nutrition, 9, 841444. ↵
- Elder, R. S., & Mohr, G. S. (2016). The crunch effect: Food sound salience as a consumption monitoring cue. Food quality and Preference, 51, 39-46. ↵
Smell that occurs through the nose.
The visual sensory system enables you to be aware of color, light level, contrast, motion and other visual stimuli. It entails all that you can see, including the intensity of light of your surroundings.
Tactile cues are signals on the skin, like pressure or vibration, that tell the brain to react. They help with movement, position, and can signal when to start eating.
The auditory sensory system is the sensory system for the sense of hearing. In nutrition context, it entails both the sounds of your food before you eat it (sizzling when baking, sparkling drinks etc.) and during consumption (e.g. cracking of crisps).