Code for SIMPLE

This document describes and provides links to the code used for the simulations reported in Brown, Neath, & Chater ("A Temporal Ratio Model of Memory"; in press; Psychological Review, July, 2007). We also summarise additional applications of the model (that appear in separate publications).

The code is provided as MATLAB files, but it is reasonably straightforward to implement the model in any language. We have made extensive use of JAVA and Excel in our own explorations of the model's behaviour.

We have re-written the code to make the structure as straightforward as possible even when this involves somewhat inefficient programming practice. For example, the published code makes extensive use of "for – end" loops, even though much more concise (and efficient) coding is possible within MATLAB. Again for transparency, we have provided separate code for each simulation reported in the paper. Each file is a MATLAB file (ending in .m) but can be opened in any text editor. For the most part the code is transparent enough to be reasonably comprehensible even without the availability of MATLAB.

We have provided two simple and heavily annotated versions of the model: a free recall version (freerecall.m) and a serial recall version (serialrecall.m). Although these do not correspond directly to any of the simulations described in the paper, they provide the most straightforward introduction to the model implementation.

The rest of the .m files, listed below, correspond to the simulations reported in the paper and are presented in the same order. In some cases both a simple and a more complex model are used to address the same set of data; in such cases an 'a' and a 'b' version are included.

Serial position effects in free recall; Murdock (1962) data, 2 s per item: serposfrtwo.m

Serial position effects in free recall; Murdock (1962) data, 1 s per item: serposfrone.m

Serial position effects in free recall; shorter retention intervals and reduced primacy: serposfrb.m

Abolition of recency after delay; Postman and Phillips (1965): delayfr.m

Serial position effects and rehearsal; Rundus (1971) and Tan and Ward (2000): rehearsefr.m

Departures from ratio rule; Cowan et al. (1997): tonepairsa.m and tonepairsb.m

Interference from previous lists; Underwood (1957): prevlistsa.m and prevlistsb.m

Forgetting over time; Peterson and Peterson (1959): timeforget.m

Forgetting with no PI; Keppel and Underwood (1962): nointa.m and nointb.m

Evidence against trace decay: Turvey et al. (1970): turvey.m

Release from PI with category shift: PIrelease.m

Release from PI with passage of time: PItime.m

Time course of forgetting: timecourse.m

Serial order over time; Nairne (1992): ordertime.m

Hierarchical memory; Nairne (1991): twodimorder.m

Phonological similarity; Henson (1996): phonsim.m

Von Restorff effects; Lippman (1980): restorff.m

Grouping effects; Hitch et al. (1996): grouping.m

Appendix: Free recall: appendixfree.m

Appendix: Serial recall: appendixserial.m

Additional Applications and Empirical Papers

List length effects; Crannell & Parrish (1957): listlength.m

Brown, G.D.A., Della Sala, S., Foster, J.K., & Vousden, J.I. (in press). Amnesia, rehearsal, and temporal distinctiveness models of recall. Psychonomic Bulletin & Review, 00, 000-000. (Applies the model to data showing abolition of primacy in hippocampal amnesia.)

Lewandowsky, S., Wright, T., & Brown, G.D.A. (in press). The interpretation of temporal isolation effects. In N. Osaka, R. Logie, & M. D'Esposito (Eds.), Working memory: Behavioral and neural correlates (pp. 000-000). Oxford University Press. (Compares encoding strength and temporal versions of the model as applied to serial recall for lists with increasing and decreasing rates of presentation.)

Neath, I., & Brown, G.D.A. (2007). Making distinctiveness models of memory distinct. In J.S. Nairne (Ed.), The foundations of remembering: Essays in honor of Henry L. Roediger III (pp. 125-140). New York: Psychology Press. (Discusses the relation between SIMPLEπs notion of distinctiveness and other accounts.)

Lewandowsky, S., Nimmo, S., & Brown, G.D.A. (in press). When temporal isolation benefits memory for serial order. Journal of Memory and Language, 00, 000-000. (Shows that temporal isplation effects can sometimes occur in memory for serial order.)

Surprenant, A.M., Neath, I., & Brown, G.D.A. (2006). Modeling age-related differences in immediate memory using SIMPLE. Journal of Memory and Language, 55, 572-586. (Applies model to age-related differences in memory for serial order.)

Neath, I., & Brown, G.D.A. (2006). Further applications of a local distinctiveness model of memory. Psychology of Learning and Motivation, 46, 201-243. (Applies model to a range of additional memory phenomena.)

Lewandowsky, S., Brown, G.D.A., Wright, T., & Nimmo, L.M. (2006). Timeless memory: Evidence against temporal distinctiveness models of short term memory for serial order. Journal of Memory and Language, 54, 20-38. (Compares temporal and non-temporal versions of the model as applied to serial recall.)

Brown, G.D.A., Morin, C., & Lewandowsky, S. (2006). Evidence for time-based models of free recall. Psychonomic Bulletin & Review, 13, 717-723. (Shows that the predicted temporal isolation effects do occur in free recall.)

Neath, I., Brown, G.D.A., McCormack, T., Chater, N., & Freeman, R. (2006). Distinctiveness models of memory and absolute identification: Evidence for local, not global, effects. Quarterly Journal of Experimental Psychology, 59, 121-135. (Applies model to local distinctiveness effects in absolute identification; see next reference for a more complete account of absolute identification.)

Stewart, N., Brown, G.D.A., & Chater, N. (2005). Absolute identification by relative judgment. Psychological Review, 112, 881-911.

Lewandowsky, S., & Brown, G.D.A. (2005). Serial recall and presentation schedule: A micro-analysis of local distinctiveness. Memory, 13, 283-292. (Implements illustrative application of the model to serial recall in which primacy effects occur at encoding and rehearsal has an effect.)

Lewandowsky, S., Duncan, M., & Brown, G.D.A. (2004). Time does not cause forgetting in short-term serial recall. Psychonomic Bulletin & Review, 11, 771-790. (Implements application of the model to serial recall in which forgetting during recall is due to output interference.)

Memory by Temporal Sampling: Talk presented at International Conference on Memory, Sydney, July 2006. (Discusses extension of time-based models to account for rehearsal effects and effects of temporal extension.)

This page last modified 30th. May 2007