Multifactorial context effects on visual recognition memory

While effects of contextual change or constancy on memory are widely found when tested by free and cued recall, there is greater inconsistency in context effects on recognition. This study employed a paradigm maximizing target-context interactivity and specificity to reveal three levels of context effects on successful retrieval, as well as context effects on the generation of false alarms, thereby revealing separable contributions of target-context binding, additive familiarity, and configural constancy. The separability of these factors enables the use of memory context effects as tools for investigating associative memory.     

Multifactorial context effects on visual recognition memory

While effects of contextual change or constancy on memory are widely found when tested by free and cued recall, there is greater inconsistency in context effects on recognition. This study employed a paradigm maximizing target–context interactivity and specificity to reveal three levels of context effects on successful retrieval, as well as context effects on the generation of false alarms, thereby revealing separable contributions of target–context binding, additive familiarity, and configural constancy. The separability of these factors enables the use of memory context effects as tools for investigating associative memory.     

Transferring voice effects in recognition memory from remembering to knowing

In five experiments, we investigated the effects of voice congruency (same vs. different voices at study and at test) on remembering and knowing in recognition memory. With low- and medium-frequency three- or four-syllable words, a voice congruency effect occurred only in remembering. With nonwords, voice congruency effects occurred both in remembering and in knowing. With nonwords and divided attention at study, the voice congruency effect transferred almost completely from remembering to knowing. By showing a transfer of effects from remembering to knowing as encoding became more impoverished, these findings support a distinctiveness/fluency account of remembering and knowing as well as the theory that remembering and knowing indicate retrieval of events from episodic and semantic memory systems, respectively.     

The effect of normative context variability on recognition memory

According to some theories of recognition memory (e.g., S. Dennis & M. S. Humphreys, 2001), the number of different contexts in which words appear determines how memorable individual occurrences of words will be: A word that occurs in a small number of different contexts should be better recognized than a word that appears in a larger number of different contexts. To empirically test this prediction, a normative measure is developed, referred to here as context variability, that estimates the number of different contexts in which words appear in everyday life. These findings confirm the prediction that words low in context variability are better recognized (on average) than words that are high in context variability.     

The influence of decision criteria upon remembering and knowing in recognition memory.

One may recognise an item as 'old' on basis of a recollective experience or by a feeling of familiarity without specific recollection. The former is called a 'remember' judgement; the latter a 'know' judgement. It has been claimed that remember and know responses reflect qualitatively distinct components of recognition memory, and not just derive from gradual differences in perceived trace strength or subjective certainty (i.e. remember judgments include memories of which one is more confident). Nonetheless, the present study examined the possibility that the distinction does relate to decision criteria placed upon a single familiarity axis (see Donaldson, 1996; Hirshman & Master, 1997). To this purpose, two groups of subjects were compared: one, which was instructed to be very conservative in their old-new judgements, while the other group was stimulated to be very lenient instead. Remember hit rates increased with more lenient criteria, whereas know hit rates did not, but false alarm rates did. While remember sensitivity was equal in the two groups, know sensitivity was lower with liberal criteria. Also it correlated with overall response bias. This lends support to the possibility that subjects not only apply an old-new decision criterion, but also set a remember-know criterion, which is affected in a similar way by liberal versus conservative instructions.     

Conceptual implicit memory and environmental context

Changes in environmental context between encoding and retrieval often affect explicit memory but research on implicit memory is equivocal. One proposal is that conceptual but not perceptual priming is influenced by context manipulations. However, findings with conceptual priming may be compromised by explicit contamination. The present study examined the effects of environmental context on conceptual explicit (category-cued recall) and implicit memory (category production). Explicit recall was reduced by context change. The implicit test results depended on test awareness (assessed with a post-test questionnaire). Among test-unaware participants, priming was equivalent for same-context and different-context groups, whereas for the test-aware, the same-context group produced more priming. Thus, when explicit contamination is controlled, changes in environmental context do not impair conceptual priming. Context dependency appears to be a general difference between implicit and explicit memory rather than a difference between conceptual and perceptual implicit memory. Finally, measures of mood indicated no changes in affect across contexts, arguing against mood mediation for the context effects in explicit recall.     

Age-related differences in recognition memory: effects of materials and context change

The study explored age-related differences in the effects of context change on recognition memory by presenting object names (Expt. 1A) or their pictures (Expt. 1B) on background scenes. Participants later attempted to recognize previously presented items on background scenes that were original, switched, blank, or new. Older adults recognized fewer word stimuli than did younger adults, and context effects were larger for older adults. With pictures, however, the age-related decrement was eliminated and context effects were reduced. The beneficial effect of context reinstatement in older adults occurs despite the finding that they are less able to recall or recognize such contexts (Experiment 2). Older adults can use context information in recognition memory at least as efficiently as younger adults when suitable materials and conditions are provided.     

The effects of context on facial affect recognition

In a sample of 325 college students, we examined how context influences judgments of facial expressions of emotion, using a newly developed facial affect recognition task in which emotional faces are superimposed upon emotional and neutral contexts. This research used a larger sample size than previous studies, included more emotions, varied the intensity level of the expressed emotion to avoid potential ceiling effects from very easy recognition, did not explicitly direct attention to the context, and aimed to understand how recognition is influenced by non-facial information, both situationally-relevant and situationally-irrelevant. Both accuracy and RT varied as a function of context. For all facial expressions of emotion other than happiness, accuracy increased when the emotion of the face and context matched, and decreased when they mismatched. For all emotions, participants responded faster when the emotion of the face and image matched and slower when they mismatched. Results suggest that the judgment of the facial expression is itself influenced by the contextual information instead of both being judged independently and then combined. Additionally, the results have implications for developing models of facial affect recognition and indicate that there are factors other than the face that can influence facial affect recognition judgments.     

The effects of elaboration on recognition memory

Two experiments were conducted to examine the effects of elaboration on recognition memory. Subjects were given either simple or complex sentences to learn and were tested for recognition of either an individual target word or the entire sentence. Complex sentences supported better recognition performance only when the test item allowed the subject to easily redintegrate the initial encoding context, either by re-presenting the encoded sentence as the test item or by constructing sentences such that the component words of the sentence could be easily redintegrated from an individual target item. It was suggested that complex, elaborate encoding established a richer trace, but that this richness can be utilized to enhance recognition only when the test conditions permit a reinstatement of the original encoding context.     

Forgotten but not gone: context effects on recognition do not require explicit memory for context

Context effects on recognition memory provide an important indirect assay of associative learning and source memory. Neuropsychological studies have indicated that such context effects may obtain even if the contexts themselves are not remembered--for example, in individuals impaired on direct tests of memory for contextual information. In contrast, a recent study indicated that the effects of temporal context reinstatement on visual recognition obtain only when the contextual information itself was explicitly recollected. Here we report that the effects of reinstatement of spatial-simultaneous context on visual object recognition memory obtain irrespective of whether those context stimuli are explicitly recognized. We suggest that spatial-simultaneous context effects might be based on ensemble unitization of target and context stimuli at encoding, whereas temporal context effects may require recollective processes.     

Role of environmental context in eyewitness memory

We investigated whether varying the environmental context will affect the magnitude of retroactive interference produced by misleading postevent information in an eyewitness memory paradigm. Previous eyewitness memory studies have typically presented the original and misleading information in the same environmental context. In this experiment, the physical contexts in which the original information and the misleading information were presented were varied, a procedure that is more analogous to what usually occurs in real world situations. We tested 288 subjects, half using the original and misleading information in the same encoding context and half using a different context for presenting the two types of information. Memory for the original event was assessed using either the standard recognition test procedure or the modified test developed by McCloskey and Zaragoza (1985). Measures of both recognition accuracy and response latency showed no difference in performance attributable to varying the environmental context. The present data replicate the findings of previous single-context experiments that showed the two recognition test procedures to produce different patterns of results. Thus, environmental context seems to play little role in determining the magnitude of the misleading postevent information effect.     

The effects of memory load and delay on facial recognition

This experiment examined the effects of memory load over three periods of delay. Following presentation of 20, 35, or 50 targets, subjects were required to select these from an equal number of distractors 10 min, 1 week, or 2 weeks later. Increased target load (independent of increases in recognition load) decreased accuracy mainly by decreasing hit rate. Increasing delay decreased accuracy largely as a result of an increased false alarm rate. Most individual ROC curves, plotted on z-coordinates, had slopes < 1. Implications of this finding for the use of d' are discussed.     

The screen memory and the act of remembering

Screen memories, seen by Freud, Greenacre and other analysts of a past generation as a key source of data for the reconstruction of psychic and historical reality, have been relatively neglected in contemporary analysis. A fresh look shows that these durable, constant memories have a dual relation to childhood experience: they memorialize both a specific organization of trauma, wish and defense, and a private childhood act of remembering. Close attention to the screen memory itself and the context in which it appears indicates that both aspects of screen memory have meaning for the individual and are represented in fantasy. Both currents of meaning can be seen in a literary screen memory and in the clinical situation, where both play out in transference and countertransference.     

The effects of list-method directed forgetting on recognition memory

University of Illinois at Urbana-Champaign, Urbana, Illinois It is an almost universally accepted claim that the list-method procedure of inducing directed forgetting does not affect recognition. However, previous studies have omitted a critical comparison in reaching this conclusion. This article reports evidence that recognition of material learnedafter cue presentation is superior for conditions in which the material that preceded cue presentation was designated as to-be-forgotten. Because the absence of an effect of directed-forgetting instructions on recognition is the linchpin of the theoretical claim that retrieval inhibition and not selective rehearsal underlies that effect, the present results call into question the need to postulate a role for inhibition in directed forgetting.     

The effect of context on discrimination and bias in recognition memory for pictures and words

When the context accompanying a to-be-remembered word is changed between study and test, recognition memory is impaired. The deleterious effect of context change on recognition memory can be viewed as support for encoding specificity theory, semantic theory, or the existence of two bases for recognition. A fourth possible interpretation, examined here, is that the effect of context change on recognition memory is due to an accompanying change in response bias, rather than a "true" decrease in sensitivity to old and new items. In two experiments, the effect of context change on discrimination and bias in recognition of simple line drawings and their names was examined. Bias was measured using two measures shown by Snodgrass and Corwin (1988) to be theoretically independent of their associated discrimination measures. Context change produced marked conservatism in response bias in both experiments but demonstrated an effect on discrimination in the second experiment only. The shift from a neutral to a conservative response strategy as a result of context change may also be seen in other experiments, in which the same experimental paradigm was used with a variety of stimulus materials. We suggest that the major effect of context manipulation is to produce a change in bias. A stimulus in a familiar environment appears to be more familiar than a stimulus in a strange environment, regardless of its old/new status. In addition, there appears to be a true decrease in discrimination with context change, but this is more difficult to detect. The finding that pictures, which are less polysemous than words, are as affected by context change as words are supports encoding specificity theory over semantic theory.     

Relational information and the context effect in recognition memory

A role for relational information was examined for the paradigm in which recognition-memory performance on items tested in the same context in which they were studied is compared with performance on items tested in different contexts. Over a series of five experiments, randomly formed pairs were used to manipulate the context of high-frequency English words. Comparisons were made between instructional manipulations designed to influence the use of relational information, and between yes/no, confidence rating (both between- and within-subject), and forced-choice tasks. There was a context effect not due to the use of inappropriate response strategies. However, high-criterion subjects resembled those subjects who were specifically instructed to use relational information, while low-criterion subjects showed little or no context effect. A model specifying the relationship between item and relational information and how relational information influences decisions in recognition-memory paradigms was proposed.     

Context-dependent repetition effects on recognition memory

One widely acknowledged way to improve our memory performance is to repeatedly study the to be learned material. One aspect that has received little attention in past research regards the context sensitivity of this repetition effect, that is whether the item is repeated within the same or within different contexts. The predictions of a neuro-computational model (O’Reilly & Norman, 2002) were tested in an experiment requiring participants to study visual objects either once or three times. Crucially, for half of the repeated objects the study context (encoding task, background color and screen position) remained the same (within context repetition) while for the other half the contextual features changed across repetitions (across context repetition). In addition to behavioral measures, event-related potentials (ERP) were recorded that provide complementary information on the underlying neural mechanisms during recognition. Consistent with dual-process models behavioral estimates (remember/know-procedure) demonstrate differential effects of context on memory performance, namely that recognition judgements were more dependent on familiarity when repetition occurs across contexts. In accordance with these behavioral results ERPs showed a larger early frontal old/new effect for across context repetitions as compared to within context repetitions and single presentations, i.e. an increase in familiarity following repetition across study contexts. In contrast, the late parietal old/new effect, indexing recollection did not differ between both repetition conditions. These results suggest that repetition differentially affects familiarity depending on whether it occurs within the same context or across different contexts.     

The effects of physostigmine and scopolamine on recognition memory in monkeys

The visual recognition of rhesus monkeys was evaluated by means of a delayed nonmatching-to-sample task with trial-unique objects. Each daily session consisted of two lists of 20 objects each, which untreated animals were able to recognize at approximately 75% accuracy. When they were performing at this level reliably, doses of physostigmine (0.32, 1.0, 3.2, 10.0, 32.0, 56.0 micrograms/kg), scopolamine (1.0, 3.2, 5.6, 10.0, 17.8, 32.0 micrograms/kg), or saline were administered 20 min prior to the session. Physostigmine and scopolamine produced dose-related increases and decreases, respectively, in the number of objects correctly remembered. The systematic changes in performance support the view that cholinergic mechanisms contribute to recognition memory and suggest that tasks with trial-unique objects may be particularly useful for studying the mnemonic effects of cholinergic drugs.     

The effects of symmetry and contour on recognition memory in children

Children in prekindergarten, kindergarten, and second grade were tested on a delayed match-to-sample task using abstract visual patterns. The patterns varied both in type of visual organization (unstructured, diagonally symmetrical, vertically symmetrical, and horizontally symmetrical) and in amount of contour. Following the initial memory task, we attempted to train half of the children at each grade by directing their attention to axes of symmetry; the other half of the children received a control task. Subsequently, the subjects were given a second delayed match-to-sample test. On both pre- and post-training trials, structure influenced performance, especially in the two younger groups. Vertical and horizontal symmetry generally facilitated performance in the prekindergarteners, while all three types of symmetry facilitated performance in the kindergarteners. In addition, children generally responded more accurately to patterns with lower levels of contour. They also made more like-contour than unlike-contour confusions, indicating that quantitative aspects of patterns were encoded. Group differences suggested that both processing capacity and memory increase during the age range studied. Finally, there was no indication that training improved performance at any age.     

Some effects of rhythmic context on melody recognition

The effects of rhythmic context on the ability of listeners to recognize slightly altered versions of 10-tone melodies were examined in three experiments. Listeners judged the melodic equivalence of two auditory patterns when their rhythms were either the same or different. Rhythmic variations produced large effects on a bias measure, indicating that listeners judged melodies to be alike if their rhythms were identical. However, neither rhythm nor pattern rate affected discriminability measures in the first study, in which rhythm was treated as a within subjects variable. The other two studies examined rhythmic context as a between subjects variable. In these, significant effects of temporal uncertainty due to the number and type of rhythms involved in a block of trials, as well as their assignment to standard and comparison melodies on a given trial, were apparent on both discriminability and bias measures. Results were interpreted in terms of the effect of temporal context on the rhythmic targeting of attention.