Tangible symbols are objects or pictures that are used as symbols by individuals who are not able to communicate using more conventional symbol systems. Tangible symbols bear an obvious and concrete relationship to the visual or tactile properties of the entities that they represent. They are a type of augmentative and alternative communication

Augmentative and alternative communication

Augmentative and alternative communication is an umbrella term that encompasses the communication methods used to supplement or replace speech or writing for those with impairments in the production or comprehension of spoken or written language...

 (AAC).

Definition

The term tangible symbols was first conceived by Charity Rowland and Philip Schweigert, and refers to two or three-dimensional pictures or objects used as symbols to convey meaning. They can represent items, people, activities and/or events, and usually either look or feel similar to what they refer to. For example, a cup can be used as a tangible symbol to represent the activity: "drink". Tangible symbols are used as a means of communication for individuals who are unable to understand or communicate using abstract systems, such as speech or sign language

Sign language

A sign language is a language which, instead of acoustically conveyed sound patterns, uses visually transmitted sign patterns to convey meaning—simultaneously combining hand shapes, orientation and movement of the hands, arms or body, and facial expressions to fluidly express a speaker's...

.
Although Rowland and Schweigert use the term tangible symbols to refer to conceptually tangible items like two-dimensional pictures, other authors such as Beukelman and Mirenda use the term to exclusively describe three-dimensional physical objects that display concrete properties such as shape or texture.

History

Objects and pictures have been used as communication symbols for a long time. Tangible symbols emerged from Van Dijk’s work using objects as symbols to develop language in deaf-blind children. In turn, Van Dijk’s work was based on the concept "symbol formation" developed by Werner and Kaplan (1963), who theorized that "symbol formation" referred to the process of developing language by creating symbols in our minds.) Many authors have also used picture symbols, such as line drawings and photographs to develop language in individuals with little or no speech and/or cognitive disabilities.

Types of tangible symbols

Rowland and Schweigert propose that tangible symbols can be divided into hierarchical categories, ranging from most concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 to most abstract symbols:

• Identical objects are real items that are equal to their referent and are the most concrete type of tangible symbol. An example includes using a toothbrush to represent "brush your teeth". Beukelman and Mirenda includes in this category miniature objects: items that are smaller than what they symbolize, such as having a small toy toilet indicate "toilet".
• Partial/associated objects refers to a portion of the object they represent, such as having a shoelace symbolize "shoes", and therefore are less concrete than identical objects.
• Symbols with one or two shared features have a resemblance to their referent, like using a mould of a pretzel for "pretzel". This category is sometimes included in the partial/associated objects category.
• Artificial symbols are abstract symbols that do not have an direct resemblance to their referent, such as having a 3D shape (i.e. an apple) that is attached to a cafe door be used as the symbol for "cafe". Beukelman and Mirenda include textured symbols in this category. An example of a textured symbol is using a piece of spandex material to denote "bathing suit".
• Two-dimensional pictures, such as photographs and line drawings are the most abstract type of tangible symbols.

The type of tangible symbol used is chosen based on the cognitive and sensory

Sensory

Sensory may refer to:relating to senses or smellIn biology:* Sensory preference* Sensory system, part of the nervous system of organisms* Sensory neuron, nerve cell responsible for transmitting information about external stimuli...

 abilities of the learner. The meaning behind each symbol is not universal, which means that tangible symbols need to be constructed for the individual learner based on what is meaningful to him/her.

Who uses tangible symbols?

Individuals that can benefit from using tangible symbols include people with cognitive disabilities, sensory and/or visual impairments, and developmental disabilities. Rowland and Schweigert claim that tangible symbols do not require the use of high demands on the learner’s cognitive abilities, memory

Memory

In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

, and visual perception

Visual perception

Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...

 because they are:

• Iconic and concrete: they have a clear connection what they refer to.
• Permanent: the user does not need to recall the object, but simply be able to recognize them.
• Manipulable: can be picked up and used by the learner and who s/he is communicating with.

Furthermore, simple responses can be used with tangible items. For example, learners that are unable to speak can simply point, look or touch the object to answer a question or make a request. Finally, three-dimensional objects can be distinguished from one another using touch, and therefore they are suitable for people with visual impairments or blindness.
A study by Rowland and Schweigert found individuals who are already able to communicate using gestures or vocalizations more readily learned to use tangible symbols than do those who did not have intentional pre-symbolic communication skills. They also observed that tangible symbols may serve as a bridge to other symbol systems, including abstract symbol systems such as speech or sign language

Sign language

A sign language is a language which, instead of acoustically conveyed sound patterns, uses visually transmitted sign patterns to convey meaning—simultaneously combining hand shapes, orientation and movement of the hands, arms or body, and facial expressions to fluidly express a speaker's...

, and that learning to use tangible symbols to communicate does not hinder the acquisition of natural speech and may even promote it.