Biomedical subjects

Bennet Murdock

Publications and source records attributed to Bennet Murdock.

6 recordsLinked to original sources

PubMed2006

Decision-making models of remember-know judgments: comment on Rotello, Macmillan, and Reeder (2004).

The sum-difference theory of remembering and knowing (STREAK) provides a sophisticated account of many interactions in the remember-know (R-K) area (C. M. Rotello, N. A. Macmillan, & J. A. Reeder, 2004). It assumes 2 orthogonal strength dimensions and oblique criterion planes. Another dual-process model (J. T. Wixted & V. Stretch, 2004) with one decision axis has also been applied to R-K judgments with considerable success and provides new insights into the processes involved. An analysis of the 4 major R-K interactions can also be explained by a simpler one-dimensional signal detection theory (J. C. Dunn, 2004a). However these models do not make contact with standard work on recognition memory, so their scope is limited. To bridge this gap, a global-matching model (a theory of distributed associative memory [TODAM]) for R-K judgments is proposed. This model can produce good fits to the data, and there are established experimental manipulations with which to test it. It provides further support for the idea that R judgments are based on associative information, whereas K judgments are based on item information.

Cognition↗

PubMed2005

The recall of missing items.

In two experiments, we studied the recall of missing items. Short lists of common words were presented once and were followed immediately by a random permutation of all but one of the presented items. The task of the subject was to recall the missing item--that is, the item present in the study set but missing from the probe set. Experiment 1 replicated the high accuracy with five-item lists originally reported by Yntema and Trask (1963) and showed that the latencies were quite short (about 750 msec). Experiment 2 varied list length unpredictably and showed that accuracy was a function of both list length (four, five, or six items) and serial position. Latency was again quite short but was essentially independent of list length and serial position. It was possible to simulate most of the effects with the power set model with no free parameters (i.e., parameters that varied with the experimental manipulations). The results seemed to be more consistent with a direct access model (the power set model of TODAM; Murdock, 1995) than with a simple search or serial-scanning model.

Humans↗

PubMed2003

Item and associative recognition with precuing and postcuing.

M. Duncan & B. B. Murdock (2000) compared precued and postcued item recognition and serial recall showing precued-postcued differences for item recognition but not for serial recall. Precuing and postcuing refer to 2 conditions in which the instructions as to the type of recall test following the presentation of short lists of items is given before or after the list presentation. This methodology was extended here to a paired-associate task. In 2 experiments, short lists of paired associates were presented followed by single-item, old-new, or intact-rearranged pair recognition tests; test type was precued or postcued. A fast or slow presentation rate was used to discourage or encourage mediators. TODAM2 (a theory of distributed associative memory) predicts that there should be little or no cuing differences regardless of whether subjects use mediators to remember the pairs. As predicted the recognition data were essentially identical for the precued and postcued conditions.

Adolescent↗

PubMed2003

The mirror effect and the spacing effect.

In the mirror effect, there are fewer false negatives (misses) and false positives (false alarms) for rare (low-frequency) words than for common (high-frequency) words. In the spacing effect, recognition accuracy is positively related to the interval (spacing or lag) between two presentations of an item. These effects are related in that they are both manifestations of a leapfrog effect (a weaker item jumps over a stronger item). They seem to be puzzles for traditional strength theory and at least some current global-matching models. A computational strength-based model (EICL) is proposed that incorporates excitation, inhibition, and a closed-loop learning algorithm. The model consists of three nonlinear coupled stochastic difference equations, one each for excitation (x), inhibition (y), and context (z). Strength is the algebraic sum (i.e., s = x - y + z). These equations are used to form a toy lexicon that serves as a basis for the experimental manipulations. The model can simulate the mirror effect forced-choice inequalities and the spacing effect for single-item recognition, all parameters are random variables, and the same parameter values are used for both the mirror and the spacing effects. No parameter values varied with the independent variables (word frequency for the mirror effect, lag for the spacing effect), so the model, not the parameters, is doing the work.

Cues↗

PubMed2001

Judgments of Frequency and Recency in a Distributed Memory Model.

TODAM is a theory of distributed associative memory based on the convolution-correlation formalism of A. Borsellino and T. Poggio (1973, Kybernetik, 122, 113-122), and TODAM2 is a revised version which includes context, auto-associations for binding, a dual basis for item information, and mediators for associative information. It can explain some complex interactions (differential forgetting and differential attention) between item and associative information. In this paper we derive the basic expressions for the memory-probe dot product for the 2x2 cases (item and pair study crossed with item and pair probe), and then we apply these expressions to judgments of frequency (JOF) and judgments of recency (JOR). We report an experiment which tests both JOF and JOR for single items with post-cuing to control for encoding strategies and suggest an attenuation factor for repetition to improve the fits. With attenuation, TODAM2 can fit the JOR data, but the JOF fits, while not too bad, consistently predict too much dependence between item and associative information. Copyright 2001 Academic Press.

Journal Article↗

PubMedDate not supplied

Storage and retrieval of serial-order information.

In this paper I will first review some seminal work by Conrad on the storage and retrieval of serial-order information which is still very relevant today. Then I will discuss the TODAM (theory of distributed associative memory) approach to serial-order effects. I will compare the three TODAM serial-order models (the chaining model, the chunking model and the power-set model; Murdock, 1995) but concentrate on the power set model. Its original problems can be solved, but a revised and augmented version has some new problems. This paper is more of a progress report than a finished product, so the reader should be prepared to follow the twists and turns of the argument.

Acoustics↗