Biology of sensory perception
8 Multimodal Interactions
A sensory modality is the sensation that is perceived after stimulation of one of the types of receptors: chemoreceptors, thermoreceptors, or pressure receptors. Each sensory modality is processed differently by the sensory nervous system and results in a conscious or unconscious detection of the stimulus.
Multiple sensory modalities interact and influence each other, thereby affecting sensory perception, a phenomenon that is also called multimodal sensation. Sensations can be strengthened by making sure that modalities give a congruent signal.
Examples of multimodal sensations are the interaction between colour and sweetness, through expectation (e.g., red strawberries automatically taste sweeter than pale ones, because you expect them to be sweeter). Another example is the interaction between colour and expected flavour (e.g., a candy which is red is expected to taste like a red fruit, and a yellow candy is expected taste like a yellow fruit like lemon).
Examples of multimodal interactions in food and expectations are illustrated by Video 3 and Video 4. Example 2 illustrates how all our senses contribute to our sensory experiences when eating an apple.
In food reformulation, one uses multimodal interactions as a strategy to lower sugar levels, while keeping flavour and pleasantness. You will read more about this in chapter 21. Strategies for Food Reformulation.
Video 3. An illustration of the importance of visual cues on taste perception.
Video 4. An illustration of how visual cues can alter taste perception.
Example 2 – How All Senses Perceive One Apple
When eating, multiple senses work together to create the experience. For example, when eating an apple. The colour makes the apple look fresh and appealing, giving an expectation of its taste. The crunching sound when biting into it adds to the perception of its crispness. The firmness when holding the apple and the texture when biting into it give you unconsciously information about its ripeness. While chewing, the sweetness and slight tartness can be tasted, and the aroma adds to the flavour through retronasal smelling when you swallow the first bite. These sensory inputs combine to create the full eating experience and based on this experience you decide to take the next bite.
the type of sensation that is perceived after stimulation of a receptor.
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (a molecule or compound) to generate a signal.
The sense receptor that detects temperature changes, usually in the skin.
A pressure receptor, also called a mechanoreceptor, is a sensory receptor that responds to mechanical pressure or distortion. It enables you to differ between textures.