Dynamic bindings

[Lokendra Shastri]

Several recent messages about the binding problem have mentioned
solutions based on temporal synchrony. Those interested in finding 
out more about this proposal and its implications for cognitive 
models may want to take a look at the following article that
appears in the recent issue of "Behavioral and Brain Sciences":

  From simple associations to systematic reasoning: a connectionist 
  encoding of rules, variables and dynamic bindings using temporal 
  synchrony. Shastri, L. and V. Ajjanagadde. BBS, 16 (3) 1993.

A number of issues raised in the discussion are covered in the article,
accompanying commentaries and the authors' response. 

The proposed solution leads to a number of predictions about the
constraints on automatic (reflexive) processing. Some of which are:

1. A large number of instances of relations/schemas/events/.... can be
   active simultaneously. In production system (PS) terms: the working
   memory capacity underlying automatic/reflexive processing is very large.

2. A very large number of systematic mappings between relations/schemas/..
   may be computed simultaneously. In PS terms: a large number of rules
   (even those containing variables) may fire in parallel.

BUT

3. The maximum number of entites (individuals) that can be referenced by
   instances active in the working memory is small (~10). 

4. Multiple instances of the same schema/relation... may be active 
   simultaneously, but no schema/relation... may be instantiated more
   than ~3 times during an episode of reflexive reasoning.

-- Shastri

Lokendra Shastri
International Computer Science Institute
1947 Center Street, Suite 600
Berkeley, CA 94707-1105

shastri at icsi.berkeley.edu

(510) 642-4274 ext 310