The influence of forward and backward associative strength on false memories for encoding context

Two experiments examined the effects of forward associative strength (FAS) and backward associative strength (BAS) on false recollection of unstudied lure items. Themes were constructed such that four associates were strongly related to a lure item in terms of FAS or BAS and four associates were weakly related to a lure item in terms of FAS or BAS. Further, when FAS was manipulated, BAS was controlled across strong and weak associates, while FAS was controlled across strong and weak associates when BAS was manipulated. Strong associates were presented in one font while weak associates were presented in a second font. At test, lure items were disproportionately attributed to the source used to present lures' strong associates compared to lures' weak associates, both when BAS was manipulated and when FAS was manipulated. This outcome demonstrates that both BAS and FAS influence lure item false recollection, which favours global-matching models' explanation of false recollection over the explanation offered by spreading activation theories.     

The role of associative strength in children's false memory illusions

The effects of associative strength on rates of 7- and 11-year-old children's true and false memories were examined when category and Deese-Roediger-McDermott (DRM) lists were used to cue the same critical lure. Backward associative strength (BAS) was varied such that the category and DRM lists had the same strength (DRM=category), DRM lists had more BAS (DRM>category), or category lists had more BAS (DRM<category). If BAS drives children's false memories then BAS, not the type of relation across items in a list, should determine false memory production. The results confirmed this prediction using both recall and recognition measures: (1) both true and false memories increased with age, (2) true memory was better for category than DRM lists but there were no differences for false memory, and (3) at all ages, false memories varied predictably with changes in BAS but were unaffected by list-type manipulations. These findings are discussed in the context of models of false memory development.     

Vibrotactile frequency recognition: forward and backward masking effects

Forward and backward vibrotactile recognition masking was investigated in 4 subjects with 240-Hz and 160-Hz targets of 20 ms duration and four 200-Hz masks, using interstimulus intervals (ISIs) ranging from -500 to 500 ms. Two of the masks (short) were 20 ms and two (long) were 200 ms in duration. One of each set of masks was matched in subjective intensity to the targets, but the others were more intense. The range of ISIs over which masking was obtained was comparable to that found by Massaro (1970) with auditory stimuli. Both short masks produced more masking than either long mask except at short ISIs. Larger mask intensities increased masking only at very short ISIs, and longer mask durations increased backward but not forward masking.     

Backward associative strength determines source attributions given to false memories

Source attributions for falsely remembered material were investigated in two experiments. A male and a female speaker each presented either an entire word list or half of the items from each of multiple Deese-Roediger-McDermott (DRM) lists commonly used in this paradigm. In the latter condition the tendency of each list half to activate a nonpresented, critical list theme item was manipulated. All of the list halves differed in backward associative strength (BAS), and each was presented by one or the other of the two speakers. In these correlated conditions, when critical items were falsely recognized (Experiments 1 and 2) or recalled (Experiment 2), source attributions were more frequently made to the speaker of the list items with the higher average BAS. This source attribution effect appears to result from the binding of list item source characteristics to activated critical items during encoding, as opposed to being the result of a biased retrieval process. The results are interpreted as consistent with an activation/monitoring account of false memory in the DRM paradigm.     

Vowel recognition: Inferences from studies of forward and backward masking

The recognition of brief vowels was studied in forward and backward masking tasks. In a series of experiments in which both target and mask parameters were systematically varied, two populations of subjects were identified. The majority (Nonmaskers) evidenced little masking at any interstimulus interval, while relatively fewer subjects (Maskers) evidenced backward masking (but not forward masking) over a 100-200 ms interval. Increasing target set size systematically increased masking for the Maskers but not for the Nonmaskers. Adding white noise to the targets increased the extent of masking for both groups. These results suggest (1) that masking does not impose a substantive constraint on vowel perception in running speech, and (2) that multiple strategies may exist for vowel recognition.     

Modeling the effects of verbal and nonverbal pair strength on associative recognition

Operations that improve the accuracy of associative recognition can do so in qualitatively different ways. Increasing repetitions and study time increases hit rates but has small effects on false alarm rates, and the specific patterns of false alarms are dependent on the stimuli (e.g., pairs of words, pseudowords, faces, or Chinese characters). In contrast, manipulating the type of stimuli that make up pairs produces a robust mirror effect: The hit rate is greater, and the false alarm rate is lower, for better recognized stimuli. To explain these findings, a model of single-item recognition is extended to associative recognition. Within this dual-process framework, the present results suggest that words are encoded more extensively than nonverbal stimuli and that recognition of frequently encountered stimuli (words and faces) is more likely to be based on recollection than is recognition of uncommon stimuli (pseudowords and Chinese characters).     

The effect of masker duration on forward and backward masking

Temporal masking of clicks by noise was investigated using forward and backward masking paradigms. Both the noise duration and the temporal separation, ΔT, between the click and noise were varied. For very brief ΔTs (100 microsec) and for very long ΔTs (100 msec), the duration of the masker did not greatly affect the click threshold. However, for intermediate ΔTs (3 msec), the threshold increased by as much as 44 dB as the noise duration increased from 0.1 to 100 msec. Temporal weighting functions, which describe the relative effectiveness of the noise as a function of ΔT, were computed from these data.     

The effects of study order and backward associative strength on illusory recollection: A source-strength effect does not always occur

We investigated illusory recollection by dividing lists of associated words into three subsets (high, medium and low) based on their backward associative strength (BAS) to an unstudied theme. Participants studied these subsets at different visual locations on a computer screen and afterwards were given a source memory test. In Experiment 1, we varied the order in which high- and medium-BAS subsets were studied. In Experiment 2, we again manipulated study order as well as the associative strength of the medium-BAS subsets (strong or weak). Across both experiments, illusory recollection was constrained by both study order and BAS. Source attributions to the high-BAS location were more likely (a source-strength effect) when high-BAS items were studied first or studied following items of relatively low associative strength. However, attributions to the strong medium-BAS studied location were more likely when these items were studied before high-BAS items. These findings are interpreted as resulting from misbinding of source details at encoding which can be explained by the activation-monitoring theory of illusory recollection.     

The distinctiveness heuristic in false recognition and false recall

The effects of generative processing on false recognition and recall were examined in four experiments using the Deese-Roediger-McDermott false memory paradigm (Deese, 1959; Roediger & McDermott, 1995). In each experiment, a Generate condition in which subjects generated studied words from audio anagrams was compared to a Control condition in which subjects simply listened to studied words presented normally. Rates of false recognition and false recall were lower for critical lures associated with generated lists, than for critical lures associated with control lists, but only in between-subjects designs. False recall and recognition did not differ when generate and control conditions were manipulated within-subjects. This pattern of results is consistent with the distinctiveness heuristic (Schacter, Israel, & Racine, 1999), a metamemorial decision-based strategy whereby global changes in decision criteria lead to reductions of false memories. This retrieval-based monitoring mechanism appears to operate in a similar fashion in reducing false recognition and false recall.     

The distinctiveness heuristic in false recognition and false recall

The effects of generative processing on false recognition and recall were examined in four experiments using the Deese-Roediger-McDermott false memory paradigm (Deese, 1959 Deese, J. 1959. On the prediction of occurrence of particular verbal intrusions in immediate recall. Journal of Experimental Psychology, 58: 17–22. [Crossref], [PubMed] , [Google Scholar]; Roediger & McDermott, 1995 Roediger, H. L. and McDermott, K. B. 1995. Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21: 803–814. [Crossref], [Web of Science ®] , [Google Scholar]). In each experiment, a Generate condition in which subjects generated studied words from audio anagrams was compared to a Control condition in which subjects simply listened to studied words presented normally. Rates of false recognition and false recall were lower for critical lures associated with generated lists, than for critical lures associated with control lists, but only in between-subjects designs. False recall and recognition did not differ when generate and control conditions were manipulated within-subjects. This pattern of results is consistent with the distinctiveness heuristic (Schacter, Israel, & Racine, 1999 Schacter, D. L., Israel, L. and Racine, C. 1999. Suppressing false recognition in younger and older adults: The distinctiveness heuristic. Journal of Memory and Language, 40: 1–24. [Crossref], [Web of Science ®] , [Google Scholar]), a metamemorial decision-based strategy whereby global changes in decision criteria lead to reductions of false memories. This retrieval-based monitoring mechanism appears to operate in a similar fashion in reducing false recognition and false recall.     

Relative effectiveness of concurrent forward/backward versus simple forward and simple backward Pavlovian conditioning procedures

Concurrent forward/backward Pavlovian conditioning procedures were compared with simple forward and simple backward procedures for differential excitatory and inhibitory conditioning. Four groups of dogs each received 30 shocks while restrained in a Pavlovian harness. One group of dogs (CON) received concurrent conditioning with a clicker signaling shocks and with a tone following shocks. For another group of dogs (SF), a clicker signaled the shocks, whereas the tone was randomly related to shocks. For a third group (SB), the tone followed shock termination, whereas the clicker was randomly related to shocks. For a fourth group (TRC), both the clicker and the tone were randomly related to shocks. All stimuli were then superimposed on a temporally paced avoidance baseline and their associative properties were assessed relative to the TRC group. Differential excitatory-inhibitory conditioning was significantly reduced in the concurrent procedure relative to that which occurred in the simple conditioning procedures despite exactly equal CS + -US and US-CS-contingencies. These results were interpreted with reference to contextual conditioning effects predicted by the Rescorla-Wagner conditioning model and the theoretical issue of independence vs. interdependence of CS-US associative strengths.     

Auditory forward and backward masking interaction

Recent research on forward masking and backward masking has led us to the hypothesis that combined forward and backward masking may involve at least two different types of interaction patterns. The previously documented interaction results in masking are greater than predicted by the simple summation of masking effects obtained with each masker alone (Lynn & Small, 1977; Patterson, 1971; Wilson & Carhart, 1971). Another possible type of interaction is based upon the finding that backward masking, but not forward masking, can be reduced by cues providing timing information (Puleo & Pastore, 1980). A forward masker appears to involve minimum temporal uncertainty (Pastore & Freda, 1980) and, therefore, should be able to act as such a source of timing information to reduce the contribution of a later occurring backward masker. Both types of interaction patterns were found, with the specific forward and backward masker parameters determining which pattern is observed.     

Comparing excitatory backward and forward conditioning

Three Pavlovian lick suppression studies with rats were conducted to compare the role of the conditioning context in excitatory backward and forward conditioning. The experiments explored the possibility that excitatory backward conditioning, but not forward conditioning, is mediated by the context. That is, in excitatory backward conditioning, the conditioning context may function as an excitatory mediator, which supports second-order conditioning of the target cue. This possibility contrasts with traditional accounts, which suggests that common processes underlie excitatory backward and forward conditioning. Experiment 1 found that conditioned responding following backward conditioning was attenuated as a result of posttraining extinction of the training context, but the same manipulation elevated responding after forward conditioning. Experiments 2 and 3 found that posttraining and pretraining associative inflation of the context (presenting unsignalled USs) increased conditioned responding to the target of a backward conditioning procedure but either had no effect or reduced responding to the target of a forward conditioning procedure. Thus, excitatory backward and forward conditioning appear to differ in their dependence on the status of the conditioning context.     

The psychology of time: a view backward and forward

We selectively review the progress of research on the psychology of time during the past 125 years, starting with the publication of the first English-language psychological journal, The American Journal of Psychology. A number of important articles on the psychology of time appeared in this journal, including the widely cited early article by Nichols (1891). The psychology of time is a seminal topic of psychological science, and although it entered a phase of decline and even moribund neglect, the past several decades have seen a prominent renaissance of interest. This renewed vigor represents the rebirth of the recognition of the centrality of the psychology of time in human cognition and behavior. Our selective overview highlights a number of strands of progress and how they have helped lead to the present, in which the cognitive neuroscience of time and timing in the brain is one of the most fervent and fertile modern areas of brain research. We also discuss some remaining challenges and potential lines of progress.     

Effect of age on forward and backward digit spans

Abstract

A number of studies has suggested that aging is characterized by a decline in the central executive while the automatic processes (in particular operations by the phonological loop) remain intact. According to interpretation, age differences should be minimal in verbal forward digit span while they should be more important in backward verbal digit span. A sample of 1,000 subjects with ages ranging from 16 years to 79 years was used to test this hypothesis. the results show no significant effect of age on the difference between digit span forward and backward. the theoretical implications of these results are discussed.     

The effect of study modality on false recognition

A number of previous studies have shown that false recognition of critical items in the Deese/Roediger-McDermott paradigm is reduced when study items are presented visually rather than auditorily; however, this effect has not been uniformly demonstrated. We investigated three potential boundary conditions of the effect of study modality in false recognition. Experiments 1 and 2 showed no reduction in false recognition following visual study presentation when the yes-no recognition test was not preceded by a recall test. Experiment 3 showed that visual study presentation can reduce false recognition without a preceding recall test, if the recognition test uses remember-know instructions. The order of the recognition test items did not influence the effect of visual study presentation on false recognition in Experiment 1. In general, the data imply that distinctive processing at study can reduce false memory in recognition if the test demands draw attention to the dimension of distinctive processing.     

Interaction of forward and backward visual masking

An investigation was conducted into the interaction of the forward and backward masking effects of unpatterned visual stimuli. It was found that detection of a test spot was easier under conditions that should have provided both forward and backward masking than under either forward masking or backward masking alone. The implications for an integration theory of masking are discussed, and the findings are contrasted with findings on the interaction of forward and backward masking by dynamic visual noise.