Mirror Effect In Recognition Memory Research Articles

Retrieval dynamics of the strength based mirror effect in recognition memory

Abstract The strength based mirror effect (SBME) refers to an increase in hit rates (HR) and a decrease in false alarm rates (FAR) for the test lists that follow a strongly encoded study list. Earlier investigation of accuracy and reaction time distributions by fitting the diffusion model indicated a mirror effect in the drift rate parameter, which was interpreted as an indication of more conservative responses due to a shift in the drift criterion. Additionally, the starting point for the evidence accumulation was found to be more liberal for the strong test lists. In order to further investigate this paradoxical effect of list strength on these two kinds of bias estimated from the diffusion model, we employed the response-deadline procedure which provided a direct assessment of response bias early in retrieval, prior to evidence accumulation. Results from the retrieval functions indicated more liberal response bias in the list strength paradigm with both pure- and mixed-strength study lists. On the contrary, the SBME was observed at the asymptotic accuracy, suggesting that the conservative response bias might be observed later in retrieval when memory evidence has fully accumulated. In addition, comparison of the SBME across pure and mixed lists revealed that the SBME was most prominent in the pure-list paradigm, suggesting that both the differentiation and criterion shift accounts jointly explain the SBME in recognition memory.

Encoding time and the mirror effect in recognition memory: Evidence from eyetracking

Abstract Low-frequency (LF) words have higher hit rates and lower false alarm rates than high-frequency (HF) words in recognition memory, a phenomenon termed the mirror effect . Visual word recognition latencies are longer for LF words. We examined the relationship between eye fixation durations during study and later recognition memory for individual words to test whether (1) increased fixation time on a word is associated with better memory, and (2) increased fixation times on LF words can account for their hit rate advantage. In Experiments 1 and 2, words of various frequencies were presented in lists in an intentional study design. In Experiment 3, HF and LF critical words were presented in matched sentence frames in an incidental study design. In all cases, the standard frequency effect on eye movements emerged, with longer reading times for lower frequency words. At test, studied words and new words from each frequency class were presented. The hit rate portion of the mirror effect was evident in all experiments. The time spent fixating a word did predict memory performance in the intentional encoding experiments, but critically, the frequency effect on hit rates was independent of this effect. Time spent fixating a word during incidental encoding did not predict later memory performance. These results suggest that the hit rate advantage for LF words is not due to the additional time spent on these words at encoding, which is consistent with retrieval-stage models of the mirror effect.

A direct test of the differentiation mechanism: REM, BCDMEM, and the strength-based mirror effect in recognition memory

We explore competing explanations for the reduction in false alarm rate observed when studied items are strengthened. Some models, such as Retrieving Effectively from Memory (REM; Shiffrin & Steyvers, 1997), attribute the false alarm rate reduction to differentiation, a process in which strengthening memory traces at study directly reduces the memory evidence for lure items. Models with no differentiation mechanism, such as the Bind-Cue-Decide Model of Episodic Memory (BCDMEM; Dennis & Humphreys, 2001), explain the false alarm rate reduction in terms of the strength of items expected at retrieval. To contrast these explanations, we separately manipulated item strength at encoding and retrieval. Participants studied mixed lists of weak and strong items. Weak items were always presented once. On separate lists, strong items were either presented twice (strong-2X) or five times (strong-5X). Within each strength condition, participants completed separate tests with mixed (strong and weak) targets, pure weak targets, or pure strong targets. They were correctly informed of the type of target on each test. Results showed that false alarm rates decreased from the strong-2X condition to the strong-5X condition for the mixed and pure-strong tests, but not for the pure-weak tests. That is, false alarm rates were determined by the strength of targets appearing on the test, not by the content of the study list. The results support BCDMEM’s expectation-based explanation and not REM’s differentiation-based explanation.

Global subjective memorability and the strength-based mirror effect in recognition memory

Between-list manipulations of memory strength through repetition commonly generate a mirror effect, with more hits and fewer false alarms for strengthened items. However, this pattern is rarely seen with within-list manipulations of strength. In three experiments, we investigated the conditions under which a within-list mirror effect of strength (items presented once or thrice) is observed. In Experiments 1 and 2, we indirectly manipulated the overall subjective memorability of the studied lists by varying the proportion of nonwords. A within-list mirror effect was observed only in Experiment 2, in which a higher proportion of nonwords was presented in the study list. In Experiment 3, the presentation duration for each item (0.5 vs. 3 sec) was manipulated between groups with the purpose of affecting subjective memorability. A within-list mirror effect was observed only for the short presentation durations. Thus, across three experiments, we found the within-list mirror effect only under conditions of poor overall subjective memorability. We propose that when the overall subjective memorability is low, people switch their response strategy on an item-by-item basis and that this generates the observed mirror effect.

FMRI evidence of word frequency and strength effects during episodic memory encoding

Word frequency (WF) and strength effects are two important phenomena associated with episodic memory. The former refers to the superior hit-rate (HR) for low (LF) compared to high frequency (HF) words in recognition memory, while the latter describes the incremental effect(s) upon HRs associated with repeating an item at study. Using the “subsequent memory” method with event-related fMRI, we tested the attention-at-encoding (AE) [M. Glanzer, J.K. Adams, The mirror effect in recognition memory: data and theory, J. Exp. Psychol.: Learn Mem. Cogn. 16 (1990) 5–16] explanation of the WF effect. In addition to investigating encoding strength, we addressed if study involves accessing prior representations of repeated items via the same mechanism as that at test [J.L. McClelland, M. Chappell, Familiarity breeds differentiation: a subjective-likelihood approach to the effects of experience in recognition memory, Psychol. Rev. 105 (1998) 724–760], entailing recollection [K.J. Malmberg, J.E. Holden, R.M. Shiffrin, Modeling the effects of repetitions, similarity, and normative word frequency on judgments of frequency and recognition memory, J. Exp. Psychol.: Learn Mem. Cogn. 30 (2004) 319–331] and whether less processing effort is entailed for encoding each repetition [M. Cary, L.M. Reder, A dual-process account of the list-length and strength-based mirror effects in recognition, J. Mem. Lang. 49 (2003) 231–248]. The increased BOLD responses observed in the left inferior prefrontal cortex (LIPC) for the WF effect provide support for an AE account. Less effort does appear to be required for encoding each repetition of an item, as reduced BOLD responses were observed in the LIPC and left lateral temporal cortex; both regions demonstrated increased responses in the conventional subsequent memory analysis. At test, a left lateral parietal BOLD response was observed for studied versus unstudied items, while only medial parietal activity was observed for repeated items at study, indicating that accessing prior representations at encoding does not necessarily occur via the same mechanism as that at test, and is unlikely to involve a conscious recall-like process such as recollection. This information may prove useful for constraining cognitive theories of episodic memory.

The variance theory of the mirror effect in recognition memory.

The mirror effect refers to a rather general empirical finding showing that, for two classes of stimuli, the class with the higher hit rates also has a lower false alarm rate. In this article, a parsimonious theory is proposed to account for the mirror effect regarding, specifically, high- and low-frequency items and the associated receiver-operating curves. The theory is implemented in a recurrent network in which one layer represents items and the other represents contexts. It is shown that the frequency mirror effect is found in this simple network if the decision is based on counting the number of active nodes in such a way that performance is optimal or near optimal. The optimal performance requires that the number of active nodes is low, only nodes active in the encoded representation are counted, the activation threshold is set between the old and the new distributions, and normalization is based on the variance of the input. Owing to the interference caused by encoding the to-be-recognized item in several preexperimental contexts, the variance of the input to the context layer is greater for high- than for low-frequency items, which yields lower hit rates and higher false alarm rates for high- than for low-frequency items. Although initially the theory was proposed to account for the mirror effect with respect to word frequency, subsequent simulations have shown that the theory also accounts for strength-based mirror effects within a list and between lists. In this case, consistent with experimental data, the variance theory suggests that focusing attention to the more difficult class within a list affects the hit rate, but not the false alarm rate and not the standard deviations of the underlying density, leading to no mirror effect.

Response distribution as an explanation of the mirror effect.

Response distribution has recently been proposed as an explanation of the mirror effect in recognition memory. According to the proposal, participants presented with distinctive sets of items (e.g., low- and high-frequency words) vary their responses to give an equal number of positive responses (e.g., the sum of hits and false alarms) to each set. Four experiments tested this proposal. Two experiments showed that the mirror effect is present in the absence of distinctive sets of items. Two experiments showed that the mirror effects is present in the absence of response equalization. Wherever the response distribution hypothesis can be tested, it fails.

Retrieval constraints and the mirror effect.

Six experiments tested the hypothesis that the mirror effect in recognition memory reflects a deliberate, postretrieval assessment of the test item's memorability. Both word frequency and concreteness were varied, and constraints at retrieval were manipulated in 2 ways: Three experiments compared recognition tested either alone or while performing a secondary task, and 3 experiments used the response-signal method to control recognition processing time. Contrary to the hypothesis, the mirror effect was not eliminated or attenuated by either kind of retrieval constraint. Moreover, both retrieval manipulations induced mirror effects of their own. Current recognition-memory theories appear inadequate to explain the results

Forgetting and the mirror effect in recognition memory: Concentering of underlying distributions.

Forgetting and the mirror effect in recognition memory: Concentering of underlying distributions.

Forgetting and the mirror effect in recognition memory: Concentering of underlying distributions.

The mirror effect is a strong regularity in recognition memory: If there are two conditions, A and B, with A giving higher recognition accuracy, then old items in A are recognized as old better than old items in B, and also new items in A are recognized as new better than new items in B. The mirror effect is explained by attention/likelihood theory, which also makes several new, counterintuitive predictions. One is that any variable, such as forgetting, that affects recognition changes the responses to new as well as old stimuli. In terms of underlying distributions, forgetting produces concentering, the bilateral movement of distributions, both new (noise) and old (signal), toward a midpoint. Data from two forced-choice experiments are reported that support the prediction of concentering and other predictions drawn from the theory. It is argued that current theories of memory, which are strength theories, cannot handle these regularities.

The mirror effect in recognition memory: Data and theory.

The mirror effect is a regularity in recognition memory that requires reexamination of current views of memory. Five experiments that further support and extended the generality of the mirror effect are reported. The first two experiments vary word frequency. The third and fourth vary both word frequency and concreteness. The fifth experiment varies word frequency, concreteness, and the subject's operations on the words. The experiments furnish data on the stability of the effect, its relation to response times, its extension to multiple mirror effects, and its extension beyond stimulus variables to operation variables. A theory of the effect and predictions that derive from the theory are presented.

The mirror effect in recognition memory: Data and theory.

The mirror effect in recognition memory: Data and theory.

The mirror effect in recognition memory.

The mirror effect in recognition memory refers to the fact that, with several different classes of stimuli, performance on new items from each class mirrors (is correlated with) performance on the corresponding classes of old items. Classes of stimuli that are accurately recognized as old when old are also accurately recognized as new when new; those that are poorly recognized as old when old are also poorly recognized as new when new. The statement above is shown not to be a tautology. A survey demonstrates that the effect holds for several types of variables (ways to classify stimuli)—word frequency, concreteness, meaningfulness, and others. The survey includes a total of 80 findings. The theoretical implications of the effect are considered.