The Cognitive Processing System

Patterns tend to have many component parts.  So whether you are a template, feature or structural theorist, you have to ask the question about how the cognitive processing system goes about analyzing these various parts.

1. Serial processing is processing that carries out one operation at a time.  In other words, you process a pattern one feature at a time.

2. Parallel processing is processing that carries out more than one operation at a time.  In other words, you process many of the features of a pattern at the same time.

3. The context in which we view a pattern is also important.  For example, we can identify a letter more rapidly if it is part of a meaningful word when compared to our speed of identifying a letter presented alone or in a non word.  This is called the word superiority effect and it is a good example of top-down processing. Knowledge about the words of a language stored in long-term memory interact with incoming letter features to give information about what letters are in a word.  This results in faster times for recognizing the letter.

1. The interactive activation model that tries to explain the word superiority effect is diagrammed below.  The fat arrows indicate excitatory connections between the levels of processing.  Excitatory connections give positive evidence for the identity of a letter or word.  The narrow arrows are inhibitory connections that provide negative evidence for the presence of letter or word. For example, a straight vertical line feature would be positive evidence for a number of uppercase English letters but not for others.

2. The presence of a vertical line indicates that some letters are possible while others are not.  The impossible ones are inhibited while the possible ones move on to the next level.  At the word level, knowledge of where in a word a particular letter is likely to fall (beginning, middle, end) also inhibits some letters from the mix, leaving others that are more likely.   The interaction between our knowledge of words and the incoming features gives rise to faster letter recognition when letters are presented in the context of meaningful words.

3. In the diagram below, notice that the arrows point in one direction between the feature and the letter levels while they point in two directions between the letter and the word levels.  The two-directional arrows describe the top-down processing component of this model whereby our knowledge of words and the placement of letters within those words is influencing the speed with which we can recognize individual letter features.



Figure 2.1

This concludes the lesson 2 commentary please complete the Practice Quiz before moving onto lesson 3.