Comparing cognition by integrating concept learning,proactive interference,and list memory

This article describes an approach for training a variety of species to learn the abstract concept of same/different, which in turn forms the basis for testing proactive interference and list memory. The stimulus set for concept-learning training was progressively doubled from 8, 16, 32, 64, 128 . . . to 1,024 different pictures with novel-stimulus transfer following learning. All species fully learned the same/different abstract concept: capuchin and rhesus monkeys learned more readily than pigeons; nutcrackers and magpies were at least equivalent to monkeys and transferred somewhat better following initial training sets. A similar task using the 1,024-picture set plus delays was used to test proactive interference on occasional trials. Pigeons revealed greater interference with 10-s than with 1-s delays, whereas delay time had no effect on rhesus monkeys, suggesting that the monkeys’ interference was event based. This same single-item same/different task was expanded to a 4-item list memory task to test animal list memory. Humans were tested similarly with lists of kaleidoscope pictures. Delays between the list and test were manipulated, resulting in strong initial recency effects (i.e., strong 4th-item memory) at short delays and changing to a strong primacy effect (i.e., strong 1st-item memory) at long delays (pigeons 0-s to 10-s delays; monkeys 0-s to 30-s delays; humans 0-s to 100-s delays). Results and findings are discussed in terms of these species’ cognition and memory comparisons, evolutionary implications, and future directions for testing other species in these synergistically related tasks.     

The Influence of Working Memory on Reading and Creative Writing Processes in a Second Language

The present study tested both the processing and storage of functions of working memory (WM) and whether WM in low-order and high-order writing processes follows the same pattern as in reading. The influence of WM on creative writing was also tested. Forty-seven high school students participated in this study. A test of written language was administered to the subjects, comprising the following subtests spelling, vocabulary, style, logical sentence, sentence combining, thematic maturity, contextual vocabulary, syntactic maturity, contextual spelling, contextual style. A WM reading comprehension test was also conducted. The overall findings of the study indicate significant relationships between WM measures and reading and writing in English as a second language.     

Wakefulness (Not Sleep) Promotes Generalization of Word Learning in 2.5‐Year‐Old Children

Sleep enhances generalization in adults, but this has not been examined in toddlers. This study examined the impact of napping versus wakefulness on the generalization of word learning in toddlers when the contextual background changes during learning. Thirty 2.5‐year‐old children (M = 32.94, SE = 0.46) learned labels for novel categories of objects, presented on different contextual backgrounds, and were tested on their ability to generalize the labels to new exemplars after a 4‐hr delay with or without a nap. The results demonstrated that only children who did not nap were able to generalize learning. These findings have critical implications for the functions of sleep versus wakefulness in generalization, implicating a role for forgetting during wakefulness in generalization.     

Symbolic,identity, and probe delayed matching of sounds by the bottlenosed dolphin

The short-term memory for sounds of the bottlenosed dolphin was tested using symbolic, identity, and probe forms of the delayed matching-to-sample (DMS) task. The forms differed in the number (one or two) or nature (symbolic or identity matches of sample sounds) of postdelay test stimuli available as memory retrieval cues. Although symbolic DMS was difficult to learn, the final performance level was approximately equal to that for identity or probe DMS. On all tasks, the dolphin’s responses were above 80% correct through to delays of 90 sec and, in some cases, through to delays of 180 and 240 sec, the “limits” being governed mainly by the dolphin’s reluctance to continue being tested at long delays. Encoding of sample stimuli into their learned symbolic representation was hypothesized to have reduced symbolic DMS to a recognition memory task, resulting in the observed equivalence of performance with the other two recognition memory tasks. The probe DMS results, unlike those for identity or symbolic DMS, showed no significant proactive interference effects from samples of prior trials. Instead, proactive interference was traceable to the probe value of the prior trial. Overall, the auditory DMS data for the dolphin were functionally similar to results reported for monkeys tested on symbolic, identity, and probe visual DMS tasks.     

Interference and auditory short-term memory in the bottlenosed dolphin

Interference in auditory short-term memory in the bottlenosed dolphin,Tursiops truncatus (Montagu), was studied using a delayed matching-to-sample task. At each trial, one of two sample sounds, chosen randomly, was projected underwater for 4 sec and then, after a variable delay interval, both sounds were presented. A response to the sound matching the initial sample was reinforced. Correct matching was significantly reduced following short intervals between trials in combination with long delays after the sample (proactive interference), or when a near continuous irrelevant sound was inserted into the delay interval (retroactive interference). There was rapid habituation to interference if the irrelevant sound was short in duration relative to the delay interval. For both proactive and retroactive interference, the errors were predominantly responses to the sample sound appropriate to the prior trial rather than to the current trial, indicating that memory for the relative recency of events (temporal memory) was degraded by interference. When interference was deleted or minimized, temporal memory remained nearly perfect over 30-sec delay intervals, the longest tested. The importance of distinguishing between temporal memory and nontemporal, or event, memory in different forms of the delayed matching task was emphasized.     

Control of pigeons’ matching and mismatching performance by instructional cues

Pigeons were trained on a two-stimulus-shape (a plus and a circle) complex conditional discrimination that required birds to match sample and comparison stimuli on some trials and to mismatch on other trials, depending on the level of chamber illumination (bright or dark). Following acquisition, the birds were transferred to a novel color (red and green) task. For half of the birds, the contingenties between levels of illumination and the match/mismatch response requirements were consistent with training (nonreversal condition). For the remaining birds, the contingencies between levels of illumination and match/mismatch response requirements were the opposite of those established in training (reversal condition). Birds in the nonreversal condition acquired the color match/mismatch task at a significantly faster rate than birds in the reversal condition. These results indicate that relation-based responding (generalized matching/ mismatching) is subject to discriminative control.     

Pigeons’ spatial memory: V. Proactive interference in the delayed matching of key location paradigm occurs only under restricted conditions

In the delayed matching of key location procedure, pigeons must remember the location of the sample key in order to choose correctly between two comparison keys. The deleterious effect of short intertrial intervals on key location matching found in previous studies suggested that pigeons’ short-term spatial memory is affected by proactive interference. However, because a reward expectancy mechanism may account for the intertriai interval effect, additional research aimed at demonstrating proactive interference was warranted. In Experiment 1, matching accuracy did not decline from early to late trials within a session, a finding inconsistent with a proactive interference effect. In Experiment 2, evidence suggestive of proactive interference was found: Matching was more accurate when the locations that served as distractors and as samples were chosen from different sets. However, this effect could have been due to differences in task difficulty, and the results of the two subsequent experiments provided no evidence of proactive interference. In Experiment 3, the distractor on Trialn was either the location that had served as the sample on Trialn ? 1 or one that had been a sample on earlier trials. Matching accuracy was not inferior on the former type of trial. In Experiment 4, the stimuli that served as samples and distractors were taken from sets containing 2, 3, 5, or 9 locations. Matching accuracy was no worse, actually slightly better, with smaller memory set sizes. Overall, these findings suggested that pigeons’ memory for spatial location may be immune to proactive interference. However, when, in Experiment 5, an intratrial manipulation was used, clear evidence of proactive interference was found: Matching accuracy was considerably lower when the sample was preceded by the distractor for that trial than when it was preceded by the sample or by nothing. Possible reasons why interference was produced by intratrial but not intertrial manipulations are discussed, as are implications of these data for models of pigeons’ short-term spatial memory.     

One World,Two Languages: Cross‐Language Semantic Priming in Bilingual Toddlers

The interconnectedness of bilingual memory remains a topic of great debate. Semantic priming provides a powerful methodological tool with which to investigate this issue in early bilingual toddlers. Semantic priming effects were investigated in 21 bilingual toddlers (2.5 years) within and across each of their languages. Results revealed the first evidence of cross‐language and within‐language semantic priming in bilingual toddlers. However, priming effects were only observed when the prime was presented in the dominant language and were comparable in magnitude within and across languages. Findings point to high interconnectivity across languages; however, there appear to be strong influences of language dominance on semantic facilitation. Findings serve to inform and refine developmental models of bilingual memory.     

Arousal and short-term memory: Effects of caffeine and trial spacing on delayed-alternation performance

Two experiments tested the prediction of Kesner’s (1973) parallel memory-stores theory that arousal reduces retention in short-term memory. Using rats as subjects, the effect of caffeine on delayed-alternation performance in a spatial discrimination was investigated. Trial spacing was also manipulated, both alone and in combination with the drug variable. The results showed that, with massed trials, caffeine facilitated alternation at the short delay and inhibited it at the longer delays tested. Using spaced trials, caffeine decreased alternation at all delays. Spaced trials produced overall superior performance as compared with massed trials. This pattern of results is consistent with the view that caffeine reduces short-term retention but, paradoxically, can also increase performance under massed trials by decreasing proactive interference (i.e., retention) from earlier trials.     

The Ghost in the Touchscreen: Social Scaffolds Promote Learning by Toddlers

This study examined the effect of a “ghost” demonstration on toddlers’ imitation. In the ghost condition, virtual pieces moved to make a fish or boat puzzle. Fifty‐two 2.5‐ and 3‐year‐olds were tested on a touchscreen (no transfer) or with 3D pieces (transfer); children tested with 3D pieces scored above a no demonstration baseline, but children tested on the touchscreen did not. Practice on the touchscreen (n = 23) by 2.5‐ and 3‐year‐olds prior to the ghost demonstration did not improve performance. Finally, children who learned the puzzle task via a social demonstration and were tested on the touchscreen (n = 26) performed better than the ghost conditions. Taken together, these studies demonstrate that social demonstrations enhance learning from novel touchscreen tools during early childhood.     

Stronger Working Memory Reduces Sexual Risk Taking in Adolescents,Even After Controlling for Parental Influences

This study examined the prospective influence of adolescent working memory (WM) on changes in impulsivity and sexual risk taking and assessed whether this relation could be explained by confounding effects of parental influences. Data from 360 community adolescents (M_age = 13.5 ± 0.95 years; 52% female; 56% non‐Hispanic White; low‐mid socioeconomic status (SES); recruited from Philadelphia area in 2004–2005) were analyzed using structural equation modeling to predict changes in impulsivity and sexual risk taking over a 2‐year follow‐up, using baseline assessments of WM, parental monitoring, parental involvement, and SES. Stronger WM predicted reduced involvement in sexual risk taking at follow‐up, effects channeled through changes in impulsivity dimensions of “acting without thinking” and “inability to delay gratification.” Parental variables had a protective influence on adolescent impulsivity and risk involvement, but the effects of WM operated independently of parental influences.     

Visual environment and delay affect cache retrieval accuracy in a food-storing rodent

Many scatter-hoarding species use spatial memory to relocate their food caches. Two factors can affect spatial memory: the availability of landmarks in the environment, and the latency between learning and recall. Using a 2 × 2 factorial design, we determined the effect of these factors on cache retrieval accuracy in Merriam’s kangaroo rats (Dipodomys merriami). Kangaroo rats cached seeds in an arena under conditions that varied by retrieval interval (1 or 10 days) and by number of landmarks (0 or 16 landmarks). After 1 day, they recovered equal proportions of caches in both landmark conditions. After 10 days, they recovered more caches in the 16-landmark condition than in the bare condition. This is the first study to show that landmarks are necessary for accurate cache recovery after long delays. This result is consistent with maze studies that have shown that landmarks reduce proactive interference and that delay increases proactive interference.     

Effects of Cognitive Strategy Interventions and Cognitive Moderators on Word Problem Solving in Children at Risk for Problem Solving Difficulties

This study investigated the role of strategy instruction and cognitive abilities on word problem solving accuracy in children with math difficulties (MD). Elementary school children (N = 120) with and without MD were randomly assigned to 1 of 4 conditions: general‐heuristic (e.g., underline question sentence), visual‐schematic presentation (diagrams), general‐heuristic + visual‐schematic, and an untreated control. When compared to the control condition that included children with MD, an advantage at posttest was found for children with MD for the visual‐schematic‐alone condition on measures of problem solving and calculation accuracy, whereas all strategy conditions facilitated posttest performance in correctly identifying problem solving components. The results also suggested that strategy conditions drew upon different cognitive resources. The General‐heuristic condition drew primarily upon the executive component of working memory (WM), Visual‐schematic condition drew upon the visual component of WM and the combined strategies condition drew upon number processing skills.     

Working memory, fluid intelligence, and science learning

A review of the history of working memory (WM) studies finds that the concept of WM evolved from short-term memory to a multi-component system. Comparison between contemporary WM models reveals: (1) consensus that the content of WM includes not only task-relevant information, but also task-irrelevant information; (2) consensus that WM consists of phonological and visuospatial components; (3) consensus that short-term memory storage is a function of WM; (4) disagreement as to whether an independent executive control is a necessary WM component; and (5) disagreement as to whether the control function is active or passive. Methods for measuring WM differed across studies with a preponderance of various dual-tasks; little psychometric work has been done on these measures. Correlational studies supported a close relationship between WM and measures of fluid intelligence and science achievement, but we found no experimental studies on the impact of WM training on science achievement. Finally we suggest how WM research findings may be applied to improve fluid intelligence and science achievement.     

The role of working memory in spatial text processing: What benefit of imagery strategy and visuospatial abilities?

This study investigated the construction of a spatial model in relation to working memory (WM) and visuospatial abilities. Participants were trained to use either imagery or verbal strategies to process route spatial texts. Results obtained on a free recall task, a verification test and a graphic representation task showed the beneficial effect of using a strategy based on mental images. When imagery strategies were used, a concurrent articulatory task produced interference effects on recall performance, and a spatial tapping task also impaired performance as compared to the control condition. These interference effects suggest that both visuospatial and verbal WM were involved in construction of the spatial model. When repetition strategies were used, however, only the articulatory task produced interference effects, highlighting the role of the verbal WM. To elucidate how the involvement of the visuospatial component may differ in relation to visuospatial abilities, participants with good or poor ability in generation of visual images and spatial manipulation of objects were compared. The benefit of the imagery strategy was found in both groups, but whereas low-visuospatial imagery participants were sensitive to spatial interference, their high ability counterparts were not. These results question the role of imagery processes in the construction of spatial models and their relation to the visuospatial WM.     

Developmental Differences in Memory During Early Childhood: Insights From Event‐Related Potentials

Age‐related differences in behavioral and electrophysiological indices of memory were examined in 3‐ to 6‐year‐old children (N = 76). Behaviorally, no differences were observed in children's ability to identify old items; however, 3‐year‐old children were less accurate in correctly rejecting new items, and 3‐ and 4‐year‐old children recalled fewer contextual details compared to 5‐ and 6‐year‐old children. Age‐related differences in electrophysiological measures (800–1,000 ms after stimulus onset) were observed both to items recalled with contextual details, which increased between 3 and 4 years, and items recalled without contextual details, which were greatest in 5‐year‐old children, even after adjusting for global age‐related differences. These findings, interpreted within a dual‐process framework, may suggest changes in both recollection and familiarity processes during early childhood.     

State anxiety and working memory in children: A test of processing efficiency theory

This study investigated the effect of individual differences in state anxiety on tasks tapping the central executive, phonological, and visuo‐spatial components of working memory (WM). It was designed to test Eysenck and Calvo’s processing efficiency theory (PET) which suggests that the phonological and executive components of WM may be important in understanding learning outcomes in anxiety. Typically‐developing children aged 9–10 years were split into high and low state anxiety groups. They performed three WM tasks – forward and backward digit span (assumed to measure phonological and central executive components of WM respectively) and a spatial working memory task (measuring the visuo‐spatial component of WM). Measurements of task accuracy were taken as an indicator of performance outcome or effectiveness. Time taken to complete tasks and a subjective rating of mental effort were taken as measurements of performance efficiency. No differences were found between high and low state anxiety groups in task accuracy for any measure. Children in the high state anxiety group, however, took longer to complete the backward digit span task and reported increased mental effort in the forward digit span task, indicating some effect of anxiety on measures of performance efficiency.     

Picturing Objects in Infancy

Infants’ transfer of information from pictures to objects was tested by familiarizing 9‐month‐olds (N = 31) with either a color or black‐and‐white photograph of an object and observing their preferential reaching for the real target object versus a distractor. One condition tested object recognition by keeping both objects visible, and the other tested object representation by hiding both objects. On visible trials, infants reached more for the distractor, indicating they recognized the target object from its picture. On hidden trials, infants reached more for the target object, suggesting they formed a continued representation of the object based on its picture. Photograph color had no effect. Infants thus show picture‐to‐object transfer by 9 months with preferential reaching, even with black‐and‐white pictures.     

The effect of modality shifts on proactive interference in long-term memory

Two experiments examined the effects of shifts in the modality on proactive interference in long-term memory. In Experiment 1 subjects learned a 40-word list presented in one of two forms of auditory/visual change—blocked or random. In the blocked conditions, learners were presented half the words in one modality followed by the remaining 20 words in the other modality. Subjects in random conditions also received 20 nouns in each modality, but the presentation was random. Following a delay, all subjects completed an 80-item recognition test. Analysis of these data showed a definite effect (p < .001) for the random change in modality when compared to the blocked presentation. As predicted, distinct reduction in serial position effects was found with the modality of presentation was random. In contrast, the blocked presentation produced two well-defined serial position curves. In Experiment 2 the effects of a shift in the modality of presentation on proactive interference were studied with high and low conceptual rigid subjects. Four similar prose passages were presented with a modality shift taking place in the last passage in a shift condition. Subjects in nonshift conditions were presented the passages exclusively in either the auditory or visual mode. The results showed that a shift in the modality of presentation of a prose passage provided a powerful releaser from proactive interference. The superior performance of rigid thinkers regardless of experimental group membership was explained in terms of organizational memory strategies.     

Do Phonological and Executive Processes in English Learners at Risk for Reading Disabilities in Grade 1 Predict Performance in Grade 2?

This study determined the degree to which the phonological and executive components of memory reflect language‐specific capacities in reading achievement. We tested whether the memory processes in a sample of English‐language learners that played a major role in predicting second‐language acquisition and risk for reading disability (RD) in Grade 1 (Swanson, Sáez, Gerber, & Leafstedt, 2004) also predicted reading performance in Grade 2. The present results showed that Spanish short‐term memory (STM) performance in Grade 1 predicted basic Spanish‐reading skills and Spanish comprehension in Grade 2, whereas Grade 1 English STM performance predicted English vocabulary and English comprehension in Grade 2. More importantly, children at risk for RD in Grade 1 differed from the counterparts in Grade 2 on both English and Spanish measures of reading, whereas their memory deficits were isolated to Spanish STM and working memory (WM). The relationship between language‐specific processes in memory and reading are discussed.