Michael A. Stadler

Norms for word lists that create false memories

Roediger and McDermott (1995) induced false recall and false recognition for words that were not presented in lists. They had subjects study 24 lists of 15 words that were associates of a common word (called the critical target or critical lure) that was not presented in the list. False recall and false recognition of the critical target occurred frequently in response to these lists. The purpose of the current work was to provide a set of normative data for the lists Roediger and McDermott used and for 12 others developed more recently. We tested false recall and false recognition for critical targets from 36 lists. Despite the fact that all lists were constructed to produce false remembering, the diversity in their effectiveness was large—60% or more of subjects falsely recalledwindow andsleep following the appropriate lists, and false recognition for these items was greater than 80%. However, the list generated fromking led to 10% false recall and 27% false recognition. Possible reasons for these wide differences in effectiveness of the lists are discussed. These norms serve as a useful benchmark for designing experiments about false recall and false recognition in this paradigm.

True But Not False Memories Produce a Sensory Signature in Human Lateralized Brain Potentials

False memories (e.g., recognition of events that did not occur) are considered behaviorally and subjectively indistinguishable from true memories. We report that brain activity differs when true and false memories are retrieved. Strongly associated lists of words were presented to one or the other cerebral hemisphere at study. This led to lateralized brain activity for these words during a centrally presented recognition test, reflecting their lateralized encoding. This activity was absent for nonstudied but strongly associated words falsely recognized as studied items. These results indicate that studied words leave sensory signatures of study experiences that are absent for false memories. In addition, hemifield effects emerged, including a slower reaction time (RT) for false recognition of nonstudied words whose associated lists were presented to the left hemifield (i.e., right hemisphere). These false recognition responses were accompanied by frontal slow wave activity, which may reflect a differential ability of the two hemispheres with respect to semantic processing.

Varieties of positive and negative priming

Numerous recent investigations have focused on a particular relation between the roles a stimulus plays in successive displays: when a stimulus ignored by a subject on one occasion is to be attended on a succeeding occasion, reaction time to that stimulus is slowed relative to a control condition. But this is but one possible case ofnegative priming. There are other ways in which negative priming might occur, and there are several varieties of positive priming as well. All these possibilities were explored in the present experiment.

Estimating unconscious processes : Implications of a general class of models

Jacoby and his colleagues (e.g., L. L. Jacoby, J. P. Toth, & A. P. Yonelinas, 1993) have shown how the mnemonic contributions of conscious recollection and unconscious familiarity can be separated using a process-dissociation procedure based on a comparison of tasks in which consciously recollected material is to be included in vs. excluded from the responses. However, the estimate of unconscious familiarity depends on the assumptions of the model. This article describes a more general class of models in which the ratio of overlap between conscious and unconscious processes remains fixed and shows that this class of models (which includes the redundancy and exclusivity models as extreme cases) yields improbable results.

Effects of sequence length and structure on implicit serial learning

Some data suggest that, as in explicit serial learning, longer sequences are more difficult to learn implicitly. These findings have been used to support the inference that implicit learning is capacity-limited. However, investigations of the effect of sequence length on implicit learning have confounded sequence structure with sequence length. These factors were manipulated independently in 3 experiments using a serial reaction time task. The results showed that sequence structure, not sequence length, largely determines the extent of sequence learning.

Distinguishing implicit and explicit learning.

I agree with Dienes and Berry’s (1997) and Neal and Hesketh’s (1997) call for investigations of the qualitative differences between implicit and explicit learning and note that such investigations must be guided by a workable definition of what is implicit and by theories that predict what the qualitative differences might be. Following Schacter, Bowers, and Booker’s (1989) retrieval intentionality criterion, I propose using anencoding intentionality criterion to distinguish implicit from explicit learning; we can reasonably infer that implicit learning has occurred when a variable known to influence explicit learning has no effect in a comparable implicit learning condition. I then suggest that implicit learning depends on noncognitive, nonhierarchical associations, whereas explicit learning depends on cognitive, hierarchical associations, and briefly describe an experiment that confirms a qualitative difference between implicit and explicit learning predicted by this hypothesis.

Is there implicit memory without attention? A reexamination of task demands in Eich’s (1984) procedure

The relation between memory and attention has been of long-standing interest. Eich (1984) made an important discovery of implicit but not explicit memory for contextually determined homophones (e.g., taxi-FARE) presented in a channel to be ignored within a selective listening procedure. However, his slow rate of presentation of shadowing task materials may have allowed frequent attention shifts to the allegedly ignored channel. With a direct replication of Eich’s timing parameters, we reproduced his results, but when the attended channel was presented twice as fast as Eich’s, implicit memory for the to-be-ignored words vanished. Our results contradict claims of extensive semantic processing of unattended auditory information in this task.

The relationship between the Wechsler Memory Scale—Revised (WMS-R) Attention index and putative measures of Attention

Although the Wechsler Memory Scale—Revised (WMS-R; Wechsler, 1987) is one of the more frequently used measures of memory and attention, its Attention/Concentration Index (ACI) has been minimally researched. If the ACI is to be used as a measure of “attention,” the need exists to determine if it is related to other measures theoretically argued to be sensitive to attention deficits. The present study evaluated the relationship between the WMS-R ACI and other putative measures of attention by comparing individuals labeled as Attention Impaired [ACI at least 15 points < General Memory Index (GMI)] versus those labeled as Memory Impaired (GMI at least 15 points < ACI). Contrary to expectations, the Attention Impaired group scored equal to the Memory Impaired group on all measures theorized to be sensitive to attention deficits (Trails A and B time, Trails B errors, Rey AVLT interference list), except for statistically weaker performance on Trails A errors. In contrast but as expected, the Memory Impaired group scored statistically worse on all memory tests (Rey AVLT, all TPT variables). The groups also did not differ on tests argued not to be differentially affected by either attention or memory (WAIS-R FIQ, Category Test). It is concluded that the WMS-R Attention Index is not related to deficits on other measures sensitive to attention, further emphasizing the need to identify more clearly specific attention constructs.

Über Wahrnehmungsprozesse in den Koordinaten der Netzhaut und des anschaulichen Raumes

SummaryFigural after-effects (FAEs) have been measured in four conditions variing the representational relations between the inspection (I)- and test (T)- figures in respect to the retina and the objective space.1.The T-figure is exposed to the same retinal region where the previously fixated I-figure has been shown; the positions in objective space of the two figures are different (retinal FAEs).2.The T-figure lies in the same place in respect to objective space as the I-figure but their retinal positions are different (by change of fixation-mark) (spatial FAEs).3.T- and I-figures take the same retinal and spatial positions; this is the commonly used FAE-condition (retinal FAEs+spatial FAEs).4.One of the T-figures lies in the same retinal position as the I-figure, while the other T-figure (comparison-figure) has the same position in objective space as the I-figure (retinal FAEs—spatial FAEs). FAEs measured under conditions 1 and 2 show that part of the effects can be localized in the retinal coordinates and another part in the coordinates of the head (constancy of direction). The results of these two types of FAEs allowed very good predictions of the magnitude of FAEs under the conditions 3 and 4.ZusammenfassungBei vier Figuralen Nachwirkungs-Anordnungen, die die relativen Abbildungsverhältnisse der sukzessiv gezeigten Inspektions (I)- und Test (T)-Figuren variieren, wurden Figurale Nachwirkungen (FN) gemessen:1.Die T-Figur wird in dem Netzhautbereich der vorher fixierten I-Figur abgebildet; die objektive Raumlage der beiden Figuren ist verschieden (FN-retinal).2.Die T-Figur nimmt die gleiche objektive Raumlage wie die I-Figur ein; die retinale Lage der beiden Figuren ist verschieden (Fixationswechsel zwischen I und T-Periode) (FN-Raumlage).3.T- und I-Figuren nehmen die gleiche objektive Raumlage ein und werden im gleichen Netzhautbereich abgebildet (FN-retinal plus Raumlage, die übliche FN-Anordnung).4.Die T-Figur fällt in den gleichen Netzhautbereich wie vorher die I-Figur, und die Vergleichsfigur nimmt die gleiche objektive Raumlage wie die I-Figur ein (FN-retinal minus Raumlage). Unter den beiden ersten Bedingungen lassen sich jeweils FN nachweisen: bei FN gibt es einen Anteil, der in Retina-Koordinaten, und einen der richtungskonstant in Kopfkoordinaten zu lokalisieren ist. Aufgrund der Messung der beiden isolierbaren FN-Arten lassen sich die FN-Beträge unter den beiden Bedingungen 3 und 4 vorhersagen.