Level I. Pre-Intentional Behavior
Behavior is not under the individual's own control, but it reflects his general state (such as comfortable, uncomfortable, hungry or sleepy). Caregivers interpret the individual's state from behaviors such as body movements, facial expressions and sounds. In typically developing children, this stage occurs between 0 and 3 months of age.
Level II. Intentional Behavior
Behavior is under the individual's control, but it is not yet used to communicate intentionally. Caregivers interpret the individual's needs and desires from behaviors such as body movements, facial expressions, vocalizations and eye gaze. In typically developing children, this stage occurs between 3 and 8 months of age.
Level III. Unconventional Communication
INTENTIONAL COMMUNICATION BEGINS HERE, AT LEVEL III
Unconventional pre-symbolic behaviors are used intentionally to communicate. Communicative behaviors are pre-symbolic because they do not involve any sort of symbol; they are unconventional because they are not socially acceptable for us to use as we grow older. Communicative behaviors include body movements, vocalizations, facial expressions and simple gestures (such as tugging on people). In typically developing children, this stage occurs between 6 and 12 months of age.
Level IV. Conventional Communication
Conventional pre-symbolic behaviors are used intentionally to communicate. Communicative behaviors are pre-symbolic because they do not involve any sort of symbol; they are conventional because they are socially acceptable and we continue to use them to accompany our language as we mature. The meanings of some gestures may be unique to the culture in which they are used. Communicative behaviors include pointing, nodding or shaking the head, waving, hugging, and looking from a person to a desired object. Note that many of these gestures (and especially pointing) require good visual skills and may not be useful for individuals with severe vision impairment. Some vocal intonations may also be used at this stage. In typically developing children, this stage occurs between 12 and 18 months of age.
Level V. Concrete Symbols
SYMBOLIC COMMUNICATION STARTS HERE, AT LEVEL V
(symbols represent, or stand for, something else)
Concrete symbols that physically resemble what they represent, are used to communicate. Concrete symbols look like, feel like, move like or sound like what they represent. Concrete symbols include pictures, objects (such as a shoelace to represent shoe), iconic gestures (such as patting a chair to say sit down) and sounds (such as making a buzzing sound to mean bee). Most individuals skip this stage and go directly to Level VI. For some individuals concrete symbols may be the only type of symbol that makes sense to them; for others they may serve as a bridge to using abstract symbols. Typically developing children use concrete symbols in conjunction with gestures and words, generally between 12 and 24 months of age, but not as a separate stage.
Level VI. Abstract Symbols
Abstract symbols such as speech, manual signs, Brailled or printed words are used to communicate. These symbols are abstract because they are NOT physically similar to what they represent. They are used one at a time. In typically developing children, this stage occurs between 12 and 24 months of age.
Level VII. Language
Symbols (concrete or abstract) are combined into two- or three-symbol combinations ('want juice', 'me go out'), according to grammatical rules. The individual understands that the meaning of symbol combinations may differ depending upon how the symbols are ordered. In typically developing children, this stage begins around 24 months of age.
