Attention in bisensory simultaneous short-term memory

Subjects were presented with simultaneously visual and auditory material. They were instructed to attend to only one modality but were required to recall materials from both modalities, one before the other. Results supported a previous suggestion that visual recall is minimum under conditions of simultaneous presentation. That is, in situations where S is allowed to divide his attention between both inputs, visual recall was no greater than when his attention was directed away from visual input and to auditory input. It was noted that this difference in recall between the two modalities was limited to verbal material, as other data indicate the opposite effect for nonverbal material.     

Stimulus information and stimulus interference in bisensory short-term memory

An attempt was made to determine if Ss’ strategy of retaining stimulus material changed under conditions of bisensory simultaneous stimulation when one of the two inputs was relevant information as opposed to interference. Thus in Group 1 Ss were stimulated bisensorily, attended to both inputs (information), but recalled only one input. Ss in Group 2 were stimulated bisensorily, attended to only one input, and recalled only that input (interference). It was found that S’s efficiency of recall was decreased in the information condition (Group 1) but strategy was not altered. In both groups, Ss performed similarly; performance was in turn similar to that observed in the typical bisensory situation, i.e., where both channels are recalled.     

Unisensory and bisensory perceptual and memory processing in stuttering adults and normal speakers

The perceptual/memory process abilities of adult stutterers were compared with those of normal adult speakers. Unisensory tasks were used as standards for comparison of the simultaneous, bisensory processes. Subjects were tested individually on sensory oral form, manual form, and word recall tasks followed by combinations of word recall and oral form discrimination, and word recall and manual form discrimination. Four bisensory combinations were tested, and in each test subjects were asked for the discrimination of the forms or recall of the words. Results showed that on both bisensory tasks in which the subjects were asked for the words rather than the form discrimination the stutterers were significantly poorer than the normals. On the bisensory tasks in which the forms were called for, the stutterers' performances were equal to the normals. No differences were found between the groups on the three unisensory tasks. These findings are related to some processing theories and to EEG studies of word recall in adult stutterers.     

Dichotic and bisensory grouping effects

The relationship between the Gray and Wedderburn effect, the channel alternation effect and the class alternation effect was studied in dichotic and bisensory experiments using physically and semantically distinguishable word classes. With dichotic presentation all three effects were found to occur, but with bisensory presentation neither the Gray and Wedderburn effect nor the class alternation effect was detected. There were no significant differences between physically and semantically based grouping. The present investigation provides support for Broadbent's claim that the Gray and Wedderburn effect depends on the occurrence of the class alternation effect. The various dichotic and bisensory grouping effects are explicable in terms of selection by modality-specific processing systems.     

Developmental changes in infants' bisensory response to synchronous durations

The present set of studies was concerned with the development of bisensory response to synchronous durations. Infants viewed pairs of checkerboards where each member of the pair flashed at the same rate but differed in the duration of each flash. Visual preferences were studied in silence as well as in the presence of a tone whose duration and onset/offset characteristics corresponded to one member of the visual pair of stimuli. Results indicated that 3-month-old infants did not make bisensory matches of duration. In contrast, 6- and 8-month-old infants exhibited evidence of bisensory matching in that, in general, their looking at the visual stimulus corresponding in duration to the auditory stimulus was greater than was their looking at the non-corresponding stimulus. Synchrony played a major part in this matching in that when the corresponding auditory and visual stimuli were put out of phase with one another, no evidence of bisensory matching was obtained.     

Apparatus for bisensory presentation of coded signals

Apparatus capable of transmitting signals to either a vibrator or to a light, or to both vibrator and light simultaneously, is described. The basis for encoding vibrotactile and visual stimuli is varying intensities and durations of signal.     

Shadowing and monitoring for selective attention

Although shadowing has been assumed to hold attention strongly (e.g. Hochberg, 1970) this has not been demonstrated, and the incidence of errors and intrusions suggest that it is not as powerful a technique as might have been supposed. An alternative, simpler, technique would be monitoring, but Kahneman (1970) maintains that selectivity fails in the absence of a continuous response. The experiments here compare the shadowing and monitoring tasks when attentional selectivity was required, and when it was not required, and indicate that similar attentional strategies operate during the monitoring and shadowing of brief messages. The shadowing paradigm is criticized in terms of an interaction between the relative resemblance of the stimuli and the shadowing voice. It is not demonstrated that an absolute interaction takes place, but more importantly that relatively greater interference is apparent when the shadower's voice and the stimuli to be shadowed are similar than when they are distinct. It is suggested that low target detections in the unattended message may be an artifact of the processing requirements of the shadowing task.     

Effects of modality preferences on learning and recall of bisensory stimuli

The performance of visual attenders and aural attenders, as defined by performance on a bisensory digit-span task, was compared on three bisensory tasks. First, in replication of an earlier study, performance was compared on a bisensory missing-unit paradigm, in which S was required to respond with missing units from two independent sets of stimuli, each set being presented on a separate channel. The results corroborated those of an earlier study in which an interaction between modality preferences and presentation modality was found. Further, differential recall patterns were found for each of the groups. While such comparable results were not found on the other two tasks, differential performance on a bisensory paired-associate task and a bisensory connected discourse task were found. The results are interpreted in accord with Murdock’s (1967) hypotheses concerning separate sensory storage mechanisms.     

False memory in a short-term memory task

The Deese/Roediger-McDermott (DRM; Roediger & McDermott, 1995) paradigm reliably elicits false memories for critical nonpresented words in recognition tasks. The present studies used a Sternberg (1966) task with DRM lists to determine whether false memories occur in short-term memory tasks and to assess the contribution of latency data in the measurement of false memories. Subjects studied three, five, or seven items from DRM lists and responded to a single probe (studied or nonstudied). In both experiments, critical lures were falsely recognized more often than nonpresented weak associates. Latency data indicated that correct rejections of critical lures were slower than correct rejections of weakly related items at all set sizes. False alarms to critical lures were slower than hits to list items. Latency data can distinguish veridical and false memories in a short-term memory task. Results are discussed in terms of activation-monitoring models of false memory.     

Media multitasking and memory: Differences in working memory and long-term memory

Increasing access to media in the 21st century has led to a rapid rise in the prevalence of media multitasking (simultaneous use of multiple media streams). Such behavior is associated with various cognitive differences, such as difficulty filtering distracting information and increased trait impulsivity. Given the rise in media multitasking by children, adolescents, and adults, a full understanding of the cognitive profile of media multitaskers is imperative. Here we investigated the relationship between chronic media multitasking and working memory (WM) and long-term memory (LTM) performance. Four key findings are reported (1) heavy media multitaskers (HMMs) exhibited lower WM performance, regardless of whether external distraction was present or absent; (2) lower performance on multiple WM tasks predicted lower LTM performance; (3) media multitasking-related differences in memory reflected differences in discriminability rather than decision bias; and (4) attentional impulsivity correlated with media multitasking behavior and reduced WM performance. These findings suggest that chronic media multitasking is associated with a wider attentional scope/higher attentional impulsivity, which may allow goal-irrelevant information to compete with goal-relevant information. As a consequence, heavy media multitaskers are able to hold fewer or less precise goal-relevant representations in WM. HMMs’ wider attentional scope, combined with their diminished WM performance, propagates forward to yield lower LTM performance. As such, chronic media multitasking is associated with a reduced ability to draw on the past—be it very recent or more remote—to inform present behavior.     

Spatial memory in rats: electroconvulsive shock selectively disrupts working memory but spares reference memory

In two experiments rats were trained until they displayed highly accurate spatial memories when a 4-h delay was imposed between the to-be-remembered event (TBRE) and the retention test in a 12-arm radial maze. If the procedure tested only working memory (WM) electronvulsive shock (ECS) 2 h after the TBRE produced amnesia but ECS immediately after the TBRE was ineffective. If the testing procedure also involved a reference memory (RM) component, ECS degraded WM regardless of whether it was given 0 or 2 h after the TBRE. RM was not affected. With either training procedure administering ECS 2 h before the TBRE was ineffective. Thus, in the radial maze truly old spatial RM was immune to disruption by ECS while more recent WM was vulnerable. Possible explanations of the data are presented.     

Individual differences in working memory capacity predict sleep-dependent memory consolidation

Decades of research have established that "online" cognitive processes, which operate during conscious encoding and retrieval of information, contribute substantially to individual differences in memory. Furthermore, it is widely accepted that "offline" processes during sleep also contribute to memory performance. However, the question of whether individual differences in these two types of processes are related to one another remains unanswered. We investigated whether working memory capacity (WMC), a factor believed to contribute substantially to individual differences in online processing, was related to sleep-dependent declarative memory consolidation. Consistent with previous studies, memory for word pairs reliably improved after a period of sleep, whereas performance did not improve after an equal interval of wakefulness. More important, there was a significant, positive correlation between WMC and increase in memory performance after sleep but not after a period of wakefulness. The correlation between WMC and performance during initial test was not significant, suggesting that the relationship is specific to change in memory due to sleep. This suggests a fundamental underlying ability that may distinguish individuals with high memory capacity.     

Modeling human memory phenomena in a hybrid event memory system

Human event memory stores an individual’s personal experiences and produces their recollections with varying degrees of accuracy. To model this capacity, we recently developed a hybrid event memory system that combines aspects of the two main theories proposed in the philosophical literature. We aim to model a complete range of human event memory phenomena – successful remembering, misremembering, and confabulation – using this framework. In this paper, we review our hybrid event memory system and present empirical results from a remembering experiment we conducted using this system. The results show that our system successfully models the full range of human event memory usage and errors.     

Long-term semantic memory versus contextual memory in unconscious number processing

Subjects classified visible 2-digit numbers as larger or smaller than 55. Target numbers were preceded by masked 2-digit primes that were either congruent (same relation to 55) or incongruent. Experiments 1 and 2 showed prime congruency effects for stimuli never included in the set of classified visible targets, indicating subliminal priming based on long-term semantic memory. Experiments 2 and 3 went further to demonstrate paradoxical unconscious priming effects resulting from task context. For example, after repeated practice classifying 73 as larger than 55, the novel masked prime 37 paradoxically facilitated the "larger" response. In these experiments task context could induce subjects to unconsciously process only the leftmost masked prime digit, only the rightmost digit, or both independently. Across 3 experiments, subliminal priming was governed by both task context and long-term semantic memory.