Memory for verbal and nonverbal stimuli in learning disability subgroups: analysis by selective reminding

Memory for verbal and nonverbal stimuli was evaluated using selective reminding procedures in normal achieving children and four groups of disabled learners: (1) reading-spelling disabled (R-S); (2) reading-spelling-arithmetic disabled (R-S-A); (3) spelling-arithmetic disabled (S-A); and (4) arithmetic disabled (A). Each child received two analogous free-list memory tasks, one for verbal material (animal names) and the other for nonverbal material (random dot patterns). These tasks were administered using selective reminding procedures that permit separation of storage and retrieval aspects of memory by reminding children only of those words not recalled on previous trials. Results revealed that relative to controls, the A and S-A children had significantly lower storage and retrieval scores on the nonverbal task, but did not differ on the verbal task; the R-S children differed only on retrieval scores from the verbal task; and the R-S-A children on retrieval scores on the verbal task and storage and retrieval scores on the nonverbal task. Thus, results indicate that the memory performance of disabled learners varies according to (1) the type of learning problem (arithmetic vs reading), (2) the nature of the stimuli (verbal vs nonverbal), and (3) the aspect of memory being assessed (storage vs retrieval). This study provides external validation for the classification of disabled learners according to patterns of academic achievement, demonstrating a useful procedure for dealing with the intrasubject variability characteristic of disabled learners.     

The use of visual and verbal memory processes by three-year-old children

Nonverbal (imagery) materials become more effective than verbal materials in aiding memory as age increases; indeed, children under five years have shown superior memory for verbal over nonverbal materials. The present study points out and changes four commonalities in the design of studies finding this latter relationship in an attempt to determine if nonverbal materials would prove superior to verbal ones. Four six-item paired-associate lists were presented individually using a study-test procedure. Presentation of the lists involved either pictures, words, or both. Recognition was tested either verbally or visually.Results indicated that the combined visual-verbal study materials produced performance superior to visual materials alone, which in turn were superior to verbal materials alone. Recognition of pictures was superior to recognition of words, regardless of mode of input. The relationship of these results to the procedural changes made are discussed, along with implications for current hypotheses of children's use of imagery.     

Visual laterality patterns for pure- versus mixed-list presentation

In Experiment 1, an overall left visual field advantage for nonverbal form recognition was found in a pure list of forms, but an overall right visual field form recognition advantage was found when the form trials were randomly intermixed with word recognition trials. Form complexity also influenced the form recognition laterality pattern, but the complexity effects were independent of (i.e., additive with) those produced by randomly mixing forms with words. Experiment 2 found that the mixed-list laterality pattern was unchanged by a pretrial cue indicating whether a word or form would follow. Experiments 3 and 4 demonstrated that holding two nouns in memory on each trial in a pure list of forms has much the same effect on laterality pattern as mixing forms with words but that the combined effect of these two variables is no larger than the effect of either variable alone. The entire pattern of results suggests that (a) laterality patterns are caused by the interaction of several factors, (b) the effects of random mixing and concurrent verbal memory are both caused by selective left-hemisphere activation, and (c) the form-complexity effects are caused by some other mechanism--perhaps subtle difference in stimulus codability.     

Task relevant effects on the assessment of cerebral specialization for facial emotion

Hemispheric specialization for processing different types of rapidly exposed stimuli was examined in a forced choice reaction time task. Four conditions of recognition were included: tacial emotion, neutral faces, emotional words, and neutral words. Only the facial emotion condition produced a significant visual field advantage (in favor of the left visual field), but this condition did not differ significantly from the neutral face condition's left visual field superiority. The verbal conditions produced significantly decreased latencies with RVF presentation, while the LVF presentation was associated with decreased latencies on the facial conditions. These results suggested that facial recognition and affective processing cannot be separated as independent factors generating right hemisphere superiority for facial emotion perception, and that task parameters (verbal vs. nonverbal) are important influences upon effects in studies of cerebral specialization.     

Apparent shift in visual field preference after unilateral stroke

Patients with either a left- or a right-hemisphere stroke lesion scored higher in tasks of word-picture matching and of nonverbal shape matching when information was presented tachistoscopically (120 msec) to the visual field (VF) projecting to their undamaged hemisphere. Left-hemisphere stroke patients (n = 13) were dissociated from right-hemisphere stroke patients (n = 15) by low word recognition from memory and by low right VF but nearly normal left VF accuracy in word-picture matching or shape matching; the former appeared to rely upon processing of word meaning by the right hemisphere. In contrast, right-stroke patients had higher right than left VF scores in both tasks, and their discrimination of nonverbal shapes via the right VF was not different from that of controls (n = 15). Preferred processing by the VF projecting to the undamaged hemisphere appeared as a shift in perceptual asymmetry but may indicate, in support of a "direct access" model, that each hemisphere responds more or less efficiently to word and to nonverbal shape discriminations.     

Nonverbal priming in amnesia

In this experiment, we examined whether a group of well-characterized amnesic patients would exhibit normal priming for novel nonverbal materials after a single exposure. Both amnesic patients and normal control subjects studied line figures and were then given a priming test in which they were asked to reproduce both old (studied) and new (unstudied) figures after a brief exposure. The measure of priming was the number of old patterns drawn correctly relative to the number of new patterns drawn correctly. Both subject groups reproduced more old patterns than new patterns, and the effect was similar in the two groups. In contrast, amnesic patients were significantly impaired on a recognition memory test for the items that had been presented. This study contributes to recent evidence that implicit memory can support the rapid acquisition of novel verbal and nonverbal information. Perceptual priming for such material is independent of the structures damaged in amnesia.     

Contrasting cases of Italian agrammatic aphasia without comprehension disorder

This study examined the effects of different concurrent verbal memory loads on a recognition accuracy task using bilaterally presented nouns. Four different memory load conditions were examined. They varied along a size dimension of either three or six words and along a complexity dimension of either easy concrete nouns or difficult highly abstract nouns. In each of the above conditions and in one control group, order or word report was controlled and in a second control group subjects were free to report the lateralized words in any order they wished. There were 20 subjects in each of the six groups. As expected, a significant right visual field superiority for verbal processing was obtained. there were no main effects of size of memory load nor complexity of m emory load on the laterality patterns. More subtle fluctuations in the patterns were found in the form of significant interactions between memory load, order of word report, and visual field. These interaction effects suggest that words reported second in the bilateral task, are more susceptible to the interfering effects of either larger or more complex memory loads. This is particularly true for right visual field words. While these data generally support a structural model of hemispheric organization, the interaction effects suggest that modifications must be made to the basic model to account for such factors as hemispheric capacity limits and order of report in the bilateral task.     

Visual imagery ability and the recognition of verbal and nonverbal stimuli.

High and low visual imagers, defined as such primarily on the basis of spatial manipulation test performance, were required to identify tachistoscopically-presented pictures, concrete words, and abstract words varying in familiarity. Two recognition paradigms were employed, recognition threshold and recognition latency. High imagers were faster in picture recognition under both paradigms when a nonverbal set or strategy was primed and when pictures were relatively unfamiliar in the threshold paradigm. No relationship was found between imagery ability and word recognition in the visual modality, nor was visual imagery ability related to the auditory recognition of verbal and nonverbal stimuli, such as words and environmental sounds. Commonalities between these findings and others in the imagery ability literature were noted.     

Stimulus modality and working memory performance in Greek children with reading disabilities: Additional evidence for the pictorial superiority hypothesis

This study investigated the effects of stimulus presentation modality on working memory performance in children with reading disabilities (RD) and in typically developing children (TDC), all native speakers of Greek. It was hypothesized that the visual presentation of common objects would result in improved learning and recall performance as compared to the auditory presentation of stimuli. Twenty children, ages 10–12, diagnosed with RD were matched to 20 TDC age peers. The experimental tasks implemented a multitrial verbal learning paradigm incorporating three modalities: auditory, visual, and auditory plus visual. Significant group differences were noted on language, verbal and nonverbal memory, and measures of executive abilities. A mixed-model MANOVA indicated that children with RD had a slower learning curve and recalled fewer words than TDC across experimental modalities. Both groups of participants benefited from the visual presentation of objects; however, children with RD showed the greatest gains during this condition. In conclusion, working memory for common verbal items is impaired in children with RD; however, performance can be facilitated, and learning efficiency maximized, when information is presented visually. The results provide further evidence for the pictorial superiority hypothesis and the theory that pictorial presentation of verbal stimuli is adequate for dual coding.     

Developmental changes in the semantic processing of pictures and words

Second- and fifth-graders' semantic decision times for pictures and words were analyzed relative to the predictions derived from unitary- and dual-memory models. At both grade levels, word-word response latencies were greater than picture-word latencies which, in turn, were greater than picture-picture latencies. An interaction between Grade and Condition indicated that verbal access times decreased more than pictorial access times. The data fit the predictions of a memory model postulating category storage in a single memory system as opposed to simultaneous representation in verbal and nonverbal memory systems. It was concluded that with increasing experience verbal access to this single semantic system is more rapid.     

The effects of concurrent verbal and visual tasks on category learning

Current theories of category learning posit separate verbal and nonverbal learning systems. Past research suggests that the verbal system relies on verbal working memory and executive functioning and learns rule-defined categories; the nonverbal system does not rely on verbal working memory and learns non-rule-defined categories (E. M. Waldron & F. G. Ashby, 2001; D. Zeithamova & W. T. Maddox, 2006). However, relatively little research has explored the importance of visual working memory or visual processing for either system. The authors investigated the role of working memory (Experiment 1a and 1b), visual processing (Experiment 2), and executive functioning for each system, using a concurrent task methodology. It was found that visual tasks with high executive functioning demands and verbal tasks with high or low executive demands disrupted rule-defined learning, whereas any visual task, regardless of executive functioning demand, disrupted non-rule-defined learning. Taken together, these results confirm the importance of verbal working memory and executive functioning for the verbal system and provide new evidence for the importance of visual processing for the nonverbal system. These results help to clarify understanding of the nonverbal system and have implications for multiple systems theories of category learning (F. G. Ashby, L. A. Alfonso-Reese, A. U. Turken, & E. M. Waldron, 1998).     

The effect of presentation format and encoding strategy on associative memory distortion

IntroductionPrevious studies using semantically related words revealed more accurate memory when the items were encoded visually rather than auditorily and when mental images were created during encoding. However, how the level of memory distortion is affected by the creation of different mental imagery formats or by techniques that should suppress generation of mental images has rarely been investigated.ObjectiveThe aim of the present studies was to investigate the ways in which the encoding strategy affects the accuracy of memory reports for two presentation formats of semantically related words: verbal and pictorial.MethodIn experiment 1, the participants were asked to memorize either pictures or their verbal equivalents (words) from the same category, using one of two encoding strategies: uttering the words or counting backwards. In experiment 2, pictorially or auditory presented material was encoded together with the creation of either visual or auditory mental images of the items. The results of the experimental groups were compared to control groups that received no specific instruction.ResultsHigher levels of false recognition, together with lower rates of correct recognition, were observed for words, presented either visually or auditory, relative to pictures. Moreover, self-generation of additional code during the processing of information favored the reduction of false recognitions.ConclusionEncoding strategies that engaged dual coding reduced false recognition. The results are discussed within the distinctiveness heuristic phenomenon.     

Age-related decrease in recognition of emotional facial and prosodic expressions

The recognition of nonverbal emotional signals and the integration of multimodal emotional information are essential for successful social communication among humans of any age. Whereas prior studies of age dependency in the recognition of emotion often focused on either the prosodic or the facial aspect of nonverbal signals, our purpose was to create a more naturalistic setting by presenting dynamic stimuli under three experimental conditions: auditory, visual, and audiovisual. Eighty-four healthy participants (women = 44, men = 40; age range 20-70 years) were tested for their abilities to recognize emotions either mono- or bimodally on the basis of emotional (happy, alluring, angry, disgusted) and neutral nonverbal stimuli from voice and face. Additionally, we assessed visual and auditory acuity, working memory, verbal intelligence, and emotional intelligence to explore potential explanatory effects of these population parameters on the relationship between age and emotion recognition. Applying unbiased hit rates as performance measure, we analyzed data with linear regression analyses, t tests, and with mediation analyses. We found a linear, age-related decrease in emotion recognition independent of stimulus modality and emotional category. In contrast, the improvement in recognition rates associated with audiovisual integration of bimodal stimuli seems to be maintained over the life span. The reduction in emotion recognition ability at an older age could not be sufficiently explained by age-related decreases in hearing, vision, working memory, and verbal intelligence. These findings suggest alterations in social perception at a level of complexity beyond basic perceptional and cognitive abilities.     

Comparisons of memory for nonverbal auditory and visual sequential stimuli

Properties of auditory and visual sensory memory were compared by examining subjects' recognition performance of randomly generated binary auditory sequential frequency patterns and binary visual sequential color patterns within a forced-choice paradigm. Experiment 1 demonstrated serial-position effects in auditory and visual modalities consisting of both primacy and recency effects. Experiment 2 found that retention of auditory and visual information was remarkably similar when assessed across a 10 s interval. Experiments 3 and 4, taken together, showed that the recency effect in sensory memory is affected more by the type of response required (recognition vs. reproduction) than by the sensory modality employed. These studies suggest that auditory and visual sensory memory stores for nonverbal stimuli share similar properties with respect to serial-position effects and persistence over time.     

Developmental and individual differences in visual memory span

The effects of chronological age (5+, 7+, 10+, and adult), articulatory suppression and spatial ability were assessed on three measures (recognition memory, partial recall, and free recall) of visual memory span for patterns, using a procedure devised by Wilson, Scott & Power (1987). Although span increased into adulthood for all three tasks, concurrent articulatory suppression acted to reduce span for the 10-year-old and adult subjects. The ability to generate accurate visuo-spatial representations at retrieval is perfectly well developed by 7 years of age. Speed of response was lengthened for the youngest age group, but was immune to the effects of concurrent articulatory suppression. Good spatial ability was associated with higher span estimates on all tasks, regardless of age. Whilst the data support the existence of a system for representing visual patterns, which increases in capacity with increasing chronological age, the system (or processes accessing it at retrieval) is not immune to verbal recoding strategies. The independent association of spatial ability with span is taken to imply that nonverbal encoding and/or maintenance strategies can act to boost visual span from at least 5 years of age.     

Brain lesion and memory functioning: Short-term memory deficit is independent of lesion location

We analyzed the effects of patterns of brain lesions from penetrating head injuries on memory performance in participants of the Vietnam Head Injury Study (Grafman et al., 1988). Classes of lesion patterns were determined by mixture modeling (L. K. Muthén & B. O. Muthén, 1998-2004). Memory performance was assessed for short-term memory (STM), semantic memory, verbal episodic memory, and visual episodic memory. The striking finding was that large STM deficits were observed in all classes of brain-injured individuals, regardless of lesion location pattern. These effects persist despite frequent concomitant effects of depressive symptomatology and substance dependence. Smaller deficits in semantic memory, verbal episodic memory, and visual episodic memory depended on lesion location, in a manner roughly consistent with the existing neuropsychological literature. The theoretical and clinical implications of the striking, seemingly permanent STM deficits in individuals with penetrating head injuries are discussed.     

Effect of Modality in Earwitness Identification: Memory for Verbal and Nonverbal Auditory Stimuli Presented in Two Contexts

Psycholegal researchers have largely ignored the relevance of nonverbal auditory information in earwitness memory, nor have they compared its retention with visual or verbal information. Memory of nonverbal auditory stimuli was investigated in two different contexts. In Experiment 1, participants recalled more sounds (i.e., nonverbal auditory stimuli) than the sounds' verbal labels. However, with a more ecologically valid method in Experiment 2, participants recalled more verbal stimuli in conjunction with visual information than they did nonverbal stimuli. Even after a 1-week delay, participants' retention of the verbal-visual combination was highest.     

Acquisition of information from rapidly presented verbal and nonverbal stimuli

Two experiments tested recognition memory for rapidly presented stimuli. In Experiment I 16 words were presented at exposure times ranging from 25 to 500 msec followed by a yes-no recognition test. The results showed a strong dependence of memory performance on both exposure time and serial position. In Experiment II 16 random forms were presented at exposure times ranging from 125 to 2000 msec followed by a yes-no recognition test. Results for random forms showed that memory performance was strongly dependent on exposure time but not on serial position. Taken together, the results of Experiments I and II suggest qualitative encoding differences between verbal vs nonverbal stimuli.     

Immediate and delayed recognition of sequentially presented random shapes.

Two experiments tested whether short-term memory accounts for the recency effect observed with rapid sequential presentation of nonverbal stimuli. Four random shapes were presented sequentially (with no interstimulus interval) on each trial at rates of 150 msec, 250 msec, 500 msec, and 1,000 msec per stimulus. Subsequent recognition varied positively with exposure duration, ranging from 57% at 150 msec to 77% at 1,000 msec. Two serial position effects were observed: a slight decrease in recognition accuracy for the first stimulus in each sequence and a large increase in recognition for the last stimulus in each sequence. The recency effect was not altered by an intervening 30-sec delay, an intervening 30-sec copying task, or an intervening 30-sec copying and counting task. Since neither visual nor verbal distractors altered recognition accuracy, it was suggested that all shapes were processed directly into long-term memory storage. It also was hypothesized that long-term storage of a nonverbal stimulus requires identification of a distinctive feature of the stimulus and that this process may continue for a brief period after actual stimulus offset.     

Hemispheric asymmetry in recognition memory: effects of retention level on the recognition of Portuguese words

Early findings from Broca and Wernicke led to the classical view of hemispheric specialization, where the main idea relates to left-hemisphere language capabilities compared to right-hemisphere visual capabilities. Federmeier and Benjamin (2005) have suggested that semantic encoding for verbal information in the right hemisphere can be more effective when memory demands are higher. In light of this, our main goal was to study the effect of retention level of verbal information on hemispheric processes. However, regarding the cross-linguistic differences in orthography and their subsequent effects on word recognition (Frost, Katz, & Bentin, 1987), our intent was also to test prior predictions of Federmeier and Benjamin (2005) for a "shallow" orthography language, where words have a clear correspondence between graphemes and phonemes, as opposed to English, which is a "deep" orthography language. Portuguese concrete nouns were selected. The participants were submitted to a visual half-field word presentation using a continuous recognition memory paradigm. The retention level included 1, 2, 4, 8, 20 or 40 words. Results showed that recognition accuracy was higher for words studied in the right visual field, compared to those studied in the left visual field, when the retention interval included 2, 4, or 20 words. No significant differences were found for the remaining intervals. Further analysis on accuracy data for intermediate retention levels showed that recognition accuracy was higher for the 2 words retention level than for the levels including 4, 8, or 20 words; it was higher for left-hemisphere encoding as well. Our results also indicated that reaction times were slower for left-hemisphere encoding and for the 40 words retention level when compared to that of 20 words. In summary, the current results are in partial agreement with those of Federmeier and Benjamin (2005) and suggest different hemispheric memory strategies for the semantic encoding of verbal information.