When assessing symbol knowledge and association, there are a few issues to consider. Symbol assessment is often an early step in evaluating the feasibility of a symbol-based communication system, but should not determine eligibility without practical teaching of association within motivating activities. For individuals that are not able to discriminate individual symbol meaning visually, assessment based on motor learning may also be worthwhile.
For learners with complex communication needs, symbolic understanding and the metaphoric association of visual symbols to their meaning may not be naturally present in the language development process. It is possible to teach individuals how to select symbols to communicate messages without initially teaching symbol meaning or the metaphoric association of the symbol to the word - instead, the association is established through cause-and-effect learning.
Visual symbol association for MORE: The learner touches the symbol representation for MORE, and they receive more of a preferred activity. This symbol is presented in various locations, and discrimination of that symbol from others is taught by offering "more" of a preferred activity versus a non-preferred activity.
Motor learning of symbol location for MORE: The learner touches the particular location on a board or display, and they receive more of a preferred activity. This location is preserved for all occurrences of MORE, and additional motivating and non-preferred vocabulary are added to different locations on the display; each item with its unique motor plan.
The visual representation, or iconicity, for the meaning "more" may be irrelevant if the appearance -or- location is learned to mean "more" based on the consequating event. Therefore, the learner's ability to receptively identify a symbol when given a label (e.g., "Which one shows MORE?") should not qualify or disqualify them for consideration of a visually supported augmentative communication system. Due to the challenges inherent in visual association of meaning experienced by many individuals with complex communication needs, it is very useful to supplement symbol learning with motor learning principles in order to maximize functionality of any visually-based system. (More on motor learning in AAC in this previous post, HERE)
Symbol iconicity in AAC refers to the continuum that describes symbols by their ease of recognition. Three terms are sometimes used to represent levels of iconicity and describe the explicitness of symbolic representations:*
- Transparent Symbols visually resemble their referent and are highly 'guessable.' One example might be a photograph of a dog to represent the concept of DOG.
- Translucent Symbols are those that fall in the middle of the iconicity continuum. These symbols may not be readily guessable without additional information. An example would be a sparse line drawing of a dog.
- Opaque Symbols refer to symbols that do not show an obvious, visual relationship to the referent. This type of symbol assignment might be quite arbitrary. An example might be the printed word—dog. Another, common in AAC, would be the various representations for pronouns such as IT, THAT or HER. Some verbs and also multiple meaning words (e.g., TAKE, HELP, CAN or ALL DONE) may also be assigned arbitrary, opaque symbols. Manufactured vocabularies use opaque symbols for their representation of a word like GO: Unity (PRC) shows a frog jumping, Boardmaker (Dynavox) shows a green traffic light, SymbolStix shows an arrow to the right. Opaque symbols are often required in order to represent all parts of speech when working with learners that do not recognize sight-words.
*These 3 labels themselves are not consistently associated with their referent meanings in symbol-based association; be warned - they are not necessarily translucent symbols. ;)
Commercially Available Symbol Assessment Tools
TASP - The Test of Aided-Communication Symbol Performance is a commercially available kit ($299) of Boardmaker PCS icons and paper visuals that can be used to assess transparent symbol recognition (search and find the named symbol in a field of 4 to 64+), opaque symbol association, categorization (food, animals, clothing transportation, people, places, things, actions), and syntactic performance (use of symbol boards for 2- to 5-part phrase construction). I would not recommend this tool beyond the transparent symbol recognition activity for any learner new to the use of symbols; however, it may be of use for determining an experienced learner's facility with PCS symbols after some time in practice. Watch a demo, HERE.
AAC Evaluation Genie - For those with an iPad to assist in evaluation, this app ($9.99) is an excellent tool. It presents many of the same tasks included in the TASP, but with the benefit of visual and auditory reinforcement. The 14 available activities include: Visual Identification (visual scan and select), Visual Discrimination (search and select with distractors), Noun Vocabulary, Function Vocabulary (ID nouns by function), Verb Vocabulary, (visual) Category Recognition, Word Association (Go-Togethers), Category Inclusion (audio prompt, Which one is an animal?), Category Exclusion (Which one is not...), Pixon Core Vocabulary (opaque symbols), Unity Core Vocabulary (Minspeak opaque symbols), Unity Icon Patterns (Minspeak category associations), Picture Description (field of 24 Pixons, various parts of speech), Word Prediction (given a pic, discrim. written word from 3 similar-looking words). View a 12-minute demo video of the app HERE.
The Training and Technical Assistance Center at ODU has a small selection of translucent and transparent visuals to use in determining a learner's preferred level of iconicity. Download the PDF HERE.