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Ashcraft, M. H. & E. H. Stazyk (1981). Mental addition: A test of three verification models. Memory & Cognition. v9 pp 185-196

Author of the summary: Jim Davies, 1999, jim@jimdavies.org

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Models of arithmetic: The next experiment is to test the rival explanations: fast access vs. search through a network representation.

Experiment: 1
Number of Subjects: 20
Kind of Subjects: undergrads in intro psych
Method: After 20 practice trials, Ss saw 100 true addition problems, and 100 false ones, mixed up. Addends were digits. For the false ones, the split (the difference between the presented and correct answer) was either plus or minus 1, 5, 9 or 13. All answers, correct and incorrect, ranged from between 0 and 18. Thus the +- 13 could not be completely randomly assigned. Ss answered with buttons true or false for each trial.

How can the 4 stage model be altered to account for these problematic findings? Well, imagine that in parallel with the retrieval there is a process that finds the sum through gradual refinement of an answer. With this model, large splits in the false problems will be caught sooner than small splits. (p191)

Experiment: 2
This experiment used some facts with double digits. The retrieval model might predict that adding 12 and 14 would be retrieving 1+1 and 2+4.
Number of Subjects: 20
Kind of Subjects: fundergrads
Method: 46 problems were basic 100 facts.
54 contained at least one 2 digit addend.br> Answers ranged between 0 and 30.
For the false ones, the split was either plus or minus 1, 5, 9 or 13.

Conclusion: In general the revised 4 stage model was supported.

The model being proposed is a network one, so predictions can be borrowed from the network semantic literature:

Summary author's notes:

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