Practice effects and composition: A reply to Anderson.

J. R. Anderson (see record 1989-24857-001) argues that our results (R. A. Carlson et al; see record 1989-24864-001) confirm several predictions of the ACT* account of skill acquisition, including the occurrence of composition. The ACT* theory does include mechanisms that can account for the major ordinal results of our experiment. However, the quantitative implications of the mechanisms that Anderson invokes to support the occurrence of composition result in unreasonable or inconsistent predictions for this data set. These mechanisms do not account for the observed effects in our control experiment, make the composition hypothesis difficult to falsify, and involve assumptions that negate the processing speed advantage that composition would provide. We also discuss several other points made by Anderson. Our results do provide weak support for some aspects of ACT*, while emphasizing the importance of quantitatively examining interrelations among mechanisms in complex models of skill acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability, Growth, and Decline in Adult Life Span Development of Declarative Memory: Cross-Sectional and Longitudinal Data From a Population-Based Study.

Five-year changes in episodic and semantic memory were examined in a sample of 829 participants (35-80 years). A cohort-matched sample (N=967) was assessed to control for practice effects. For episodic memory, cross-sectional analyses indicated gradual age-related decrements, whereas the longitudinal data revealed no decrements before age 60, even when practice effects were adjusted for. Longitudinally, semantic memory showed minor increments until age 55, with smaller decrements in old age as compared with episodic memory. Cohort differences in educational attainment appear to account for the discrepancies between cross-sectional and longitudinal data. Collectively, the results show that age trajectories for episodic and semantic memory differ and underscore the need to control for cohort and retest effects in cross-sectional and longitudinal studies, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of the role of working memory in procedural skill acquisition.

On the basis of the ACT* production system theory of skill acquisition (Anderson, 1983a, 1987), I generated predictions concerning the role of two proposed classes of working-memory limitations in procedural learning. Individual differences analyses of a laboratory procedural learning task tested these predictions. As hypothesized, measures of controlled attention in working memory predicted initial declarative rule acquisition and proceduralization, and measures of automatic activation in working memory predicted indexes of later production composition and strengthening. Results supported a distinction between two working-memory capacity constructs that impose unique limits on processes of skill acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Problem solving and learning.

A. Newell and H. A. Simon (1972) provided a framework for understanding problem solving that can provide the needed bridge between learning and performance. Their analysis of means–ends problem solving can be viewed as a general characterization of the structure of human cognition. However, this framework needs to be elaborated with a strength concept to account for variability in problem solving behavior and improvement in problem-solving skill with practice. The ACT* theory (J. R. Anderson, 1983) is such an elaborated theory that can account for many of the results about the acquisition of problem-solving skills. Its central concept is the production rule, which plays an analogous role to the stimulus–response bond in earlier learning theories. The theory has provided a basis for constructing intelligent computer-based tutoring systems for the instruction of academic problem-solving skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory plasticity in old age: Practice gain, transfer, and maintenance.

Adult age differences in cognitive plasticity have been studied less often in working memory than in episodic memory. The authors investigated the effects of extensive working memory practice on performance improvement, transfer, and short-term maintenance of practice gains and transfer effects. Adults age 20-30 years and 70-80 years practiced a spatial working memory task with 2 levels of processing demands across 45 days for about 15 min per day. In both age groups and relative to age-matched, no-contact control groups, we found (a) substantial performance gains on the practiced task, (b) near transfer to a more demanding spatial n-back task and to numerical n-back tasks, and (c) 3-month maintenance of practice gains and near transfer effects, with decrements relative to postpractice performance among older but not younger adults. No evidence was found for far transfer to complex span tasks. The authors discuss neuronal mechanisms underlying adult age differences and similarities in patterns of plasticity and conclude that the potential of deliberate working memory practice as a tool for improving cognition in old age merits further exploration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The sea horse comes of age: Theoretical comment on Rehbein, Killiany, and Mahut (2005) and Killiany, Rehbein, and Mahut (2005).

Impairments in various aspects of learning and memory have been ascribed to the effects of damage to the hippocampal formation in adult nonhuman primates. Whether these effects reflect disturbance of a unitary process or multiple processes within the hippocampus and whether other systems may participate in these functions is unclear. After making hippocampal ablations in infant rhesus monkeys (Macaca mulatta), L. Rehbein, R. Killiany, and H. Mahut (2005) (see record 2005-06959-001) and R. Killiany, L. Rehbein, and H. Mahut (2005) (see record 2005-06959-002) reported a dissociation of effect between tasks of recognition memory and contextual retrieval (impaired) and associative learning (spared). The findings point to an ontogenetic dissociation of function within the hippocampal formation and, at the same time, support the view of the coexistence of at least two neural systems that underlie memory and learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validation of lucigenin as a chemiluminescent probe to monitor vascular superoxide as well as basal vascular nitric oxide production

Lucigenin has been widely used as a chemiluminescent substrate to monitor vascular superoxide (O*-2) formation. The validity of lucigenin for detection of O*-2 has been questioned because O*-2 is generated by lucigenin itself. It has been shown that the concentration of lucigenin is a critical parameter affecting the validity of this assay. In the present studies we evaluated a reduced concentration of lucigenin (5 microM) as a tool to quantify O*-2 production in vascular tissue. Lucigenin-induced effects on endothelial function were assessed by isometric tension recording of isolated aortic rings suspended in organ baths. The effects of lucigenin on O*-2 production were studied using spin trapping and electron spin resonance spectroscopy. Lucigenin at 250 microM but not at 5 microM caused a significant attenuation of endothelium-dependent relaxations to acetylcholine, which was prevented by pretreatment with superoxide dismutase. Spin-trapping studies revealed that lucigenin at 250 microM increased vascular O*-2 production several fold while 5 microM lucigenin did not stimulate O*-2 production. Inhibition of NO synthase by NG-momomethyl-l-arginine as well as the removal of the endothelium almost doubled lucigenin-derived chemiluminescence (LDCL), indicating that basal production of endothelium-derived NO depresses the baseline chemiluminescence signal. Thus, lucigenin at a concentration of 5 microM seems to be a sensitive and valid probe for assessing O*-2 in vascular tissue. It can also be used as an indirect probe to estimate basal vascular NO release.     

Antichymotrypsin interaction with chymotrypsin. Reactions following encounter complex formation

Serpins, serine proteinase inhibitors, form enzymatically inactive, 1:1 complexes (denoted E*I*) with their target proteinases, that only slowly release I*, in which the P1-P1' linkage is cleaved. Recently we presented evidence that the serpin antichymotrypsin (ACT, I) reacts with the serine proteinase chymotrypsin (Chtr, E) to form an E*I* complex via a three-step mechanism, E + I <==> E .I <==> EI' <==> E*I* in which EI', which retains the P1-P1' linkage, is formed in a partly or largely rate-determining step, depending on temperature (O'Malley, K. H, Nair, S. A., Rubin, H., and Cooperman, B. S. (1997) J. Biol. Chem. 272, 5354-5359). Here we extend these studies through the introduction of a new assay for the formation of the postcomplex fragment, corresponding to ACT residues 359 (the P1' residue) to 398 (the C terminus), coupled with rapid quench flow kinetic analysis. We show that the E.I encounter complex of wild type-rACT and Chtr forms both E*I* and postcomplex fragment with the same rate constant, so that both species arise from EI' conversion to E*I*. These results support our earlier conclusion that the P1-P1' linkage is preserved in EI' and imply that E*I* corresponds to a covalent adduct of E and I, either acyl enzyme or the tetrahedral intermediate formed by water attack on acyl enzyme. Furthermore, we show that the A347R (P12) variant of rACT, which is a substrate rather than an inhibitor of Chtr, has a rate constant for postcomplex fragment formation from the E.I complex very similar to that observed for WT-rACT, implying that EI' is the common intermediate from which partitioning to inhibitor and substrate pathways occurs. These results are used to elaborate a proposed scheme for ACT interaction with Chtr that is considered in the light of relevant results from studies of other serpin-serine proteinase pairs.     

Serum alpha 1-antichymotrypsin level as a marker for Alzheimer-type dementia

Excessive alpha 1-antichymotrypsin (ACT) in brain has been postulated to play a role in the pathogenesis of Alzheimer's disease (AD). We measured serum ACT by radial immunodiffusion in 57 patients with presumed AD, 110 healthy controls (24 children; 86 adults), 67 non-AD patients from a geriatric private practice and a VA nursing home, and 136 asthmatics (56 adults; 80 children) as an inflammatory disease control group. Serum ACT was significantly higher in AD (73.1 +/- 22 mg/dl) than in healthy controls (47.9 +/- 8.1 mg/dl) or non-AD patients (61.8 +/- 23.9 mg/dl). A level of 60 mg/dl best separated AD patients from controls or non-AD patients. Serial measurements served to distinguish elevations of ACT level in AD from non-AD inflammatory conditions; the ACT level in the latter returned to normal with therapy or time, but the levels in AD remained elevated. A measure of serum ACT by radial immunodiffusion can be used to support a diagnosis of AD disease but not necessarily as a screening test due to the potentially large number of false positives (26% in the population studied) should malignancy or inflammatory disease be concurrent.     

The costs of doing two things at once for young and older adults: Talking while walking, finger tapping, and ignoring speech of noise.

Young and older adults provided language samples in response to questions while walking, finger tapping, and ignoring speech or noise. The language samples were scored on 3 dimensions: fluency, complexity, and content. The hypothesis that working memory limitations affect speech production by older adults was tested by comparing baseline samples with those produced while the participants were performing the concurrent tasks. There were baseline differences: Older adults' speech was less fluent and less complex than young adults' speech. Young adults adopted a different strategy in response to the dual-task demands than older adults: They reduced sentence length and grammatical complexity. In contrast, older adults shifted to a reduced speech rate in the dual-task conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of sentence complexity on the reading comprehension of syntactic structures.

Studied the effects of sentence complexity on reading comprehension of the Minimal Distance Principle (MDP), a general psycholinguistic principle, in 102 3rd, 4th, and 5th graders. Ss were asked to identify subordinate clause subjects of sentences in a 2 * 2 factorial study with 2 levels of MDP (conforming and violating) and complexity (following and interrupting statements). Significant main effects were found for MDP (conforming sentences were easier) and complexity (following statements were easier). The MDP and complexity variables formed a significant interaction. The MDP-violating sentences produced performance characteristic of short-term memory tasks, making complex sentences, which separate subject and subordinate clause by several words, difficult to process. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming and theories of memory: A reply to Ratcliff and McKoon.

R. Ratcliff and G. McKoon (see record 1994-16298-001) attempt to buttress the case for non-spreading-activation models of associative priming by showing that first-response free association probabilities do not predict priming effects, and sequential effects in lexical decisions are predicted by at least one non-spreading-activation model. The author argues that their attempt to predict priming from free association is not informative because they did not propose a model of how association in memory is manifested in free association, these predictions depended on assumptions that are not consistent with the model tested, the compound-cue model is a poor model of sequential effects, and non-spreading-activation models still cannot explain the absence of inhibition following nonword primes when responses to the primes are not required. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Equivalence of alternate forms of six psychometric measures during repeated testing.

Analysis of scores obtained by 80 army enlisted men on the 1st 7 forms of the 6 repetitive psychometric measures developed by L. Moran and R. Mefferd (see record 1960-02367-001) indicates that (a) different forms measure the same factors, (b) the Forms * S Groups interaction effects were significant, and (c) there was an unexpected practice effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Model of social inference processes.

Presents a new model of inference processes in the social perceiver, along with the basis of the model in prior experimental results and in the ACT* cognitive theory developed by J. R. Anderson (1976, 1983). The 2 stages of the model involve different types of processing: interpretive and procedural. In the 1st stage, an inference is performed by general, domain-independent processes guided by a learned inference rule that is selected from long-term memory. In the 2nd stage, procedural stage, after much experience with a particular inferential domain, an inference process is selected without explicit search, based on a pattern match to the current goal and knowledge state. The inference becomes automatic. Existing experimental evidence supports predictions of the model in both the attribution and attitude domains. Insights and findings of current approaches to inference, including information integration and judgmental heuristics, can be encompassed within the new model in a natural way. (93 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The fan effect: A tale of two theories.

This article addresses J. R. Anderson and L. M. Reder's (see record 1999-05245-004) account of the differential fan effect reported by G. A. Radvansky, D. H. Spieler, and R. T. Zacks (see record 1993-16287-001). The differential fan effect is the finding of greater interference with an increased number of associations under some conditions, but not others, in a within-subjects mixed-list recognition test. Anderson and Reder concluded that the differential fan effects can be adequately explained by assuming differences in the weights given to concepts in long-term memory. When a broader range of data is considered, this account is less well supported. Instead, it is better to assume that the organization of information into referential representations, such as situation models, has a meaningful influence on long-term memory retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

APOE*4-associated Alzheimer's disease risk is modified by alpha 1-antichymotrypsin polymorphism

Genetic studies on Alzheimer's disease (AD), a devastating neurodegenerative disorder, have identified the apolipoprotein E (APOE) gene as a strong susceptibility marker for AD. The E*4 allele of APOE is a major risk factor for AD regardless of age of onset or family history. However, the observation that the APOE*4 allele is neither necessary nor sufficient for the expression of AD emphasizes the involvement of other environmental or genetic elements that, either in conjunction with APOE*4 or alone, increase an individual's risk of developing AD. Among the candidate genes that may affect the risk of this multifactorial disease is the gene coding for alpha 1-antichymotrypsin (ACT). Like APOE protein, ACT binds to beta-amyloid peptide (A beta P) with high affinity in the filamentous deposits found in the AD brain and serves as a strong stimulatory factor in the polymerization of A beta P into amyloid filaments. In AD brains, ACT expression is enhanced, particularly in areas that develop amyloid plaques, suggesting that ACT may play an important role in the pathogenesis of AD. Here we show that a common polymorphism in the signal peptide of ACT confers a significant risk for AD. Furthermore, the APOE*4 gene dosage effect associated with AD risk is significantly modified by the ACT polymorphism. We have also identified a unique combination of the ACT/AA and APOE 4/4 genotypes as a potential susceptibility marker for AD, as its frequency was 1/17 in the AD group compared to 1/313 in the general population control. Our data show that ACT behaves as a modifier gene that alters the AD risk conventionally associated with the APOE*4 allele.     

Models of cognitive processing: A single flexible workspace or a distributed process? Comment on Carlson, Khoo, Yaure, and Schneider.

Data provided by R. A. Carlson et al (see record 1990-24447-001) show that with practice, Ss solve computerized versions of logic gates more quickly, with fewer requests for help, and more cheaply (in simulated costs). Ss reported that they changed strategies as they became more familiar with the task, began working backwards from the goal, and used larger perceptual units of analysis. Although these results provide an interesting account of the development of problem-solving expertise, they cannot be used to differentiate between single-workspace or distributed processing models of working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prostaglandin E2 induced polymerization of human alpha-1-antichymotrypsin and suppressed its protease inhibitory activity: implications for Alzheimer''s disease

Different molecular forms of alpha-1-antichymotrypsin (ACT) in sera and cerebrospinal fluids from patients with Alzheimer's disease (AD) were detected. Monomeric and polymeric ACT were observed by polyacrylamide gel electrophoresis of both sera and cerebrospinal fluids. ACT polymers were increased in AD patients with the apolipoprotein E (APOE) 4 allele. Increased levels of inactive ACT molecules were also detected in brain homogenates of patients with the APOE 4 allele. Experimental conditions promoting in vitro polymerization of ACT and the effect of polymerization on the biological activity of this serpin were also explored. Incubation of this serpin with prostaglandins of E series (PGE 2) induced ACT polymerization and decreased its activity. Amyloid beta-peptide1-42 did not significantly affected the biological activity of ACT. Inactivation of protease inhibitors by inflammatory molecules such as PGE 2 released from activated microglia in AD brains may promote amyloid deposition and neurodegeneration.     

Sequential and coordinative complexity: Age-based processing limitations in figural transformations.

Dimensions of cognitive complexity in figural transformations were examined in the context of adult age differences. Sequential complexity was manipulated through figural transformations of single objects in a multiple-object array. Coordinative complexity was induced through spatial or nonspatial transformations of the entire array. Results confirmed the prediction that age-related slowing is larger in coordinative complexity than in sequential complexity conditions. The effect was stable across 8 sessions (Exp 1), was obtained when age groups were equated in accuracy with criterion-referenced testing (Exp 2), and was corroborated by age-differential probabilities of error types (Exps 1 and 2). A model is proposed attributing age effects under coordinative complexity to 2 factors: (1) basic-level slowing and (2) time-consuming reiterations through the processing sequence due to age-related working memory failures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attachment categories as reflections of multiple dimensions: Comment on Fraley and Spieker (2003).

Ainsworth's system of classifying patterns of attachment behavior has served the field well and will not be easily displaced--not because of a commitment by attachment researchers to the taxonomic status of these categories but rather because of difficulties lying in the way of a dimensional approach. Foremost among these is the large number of dimensions used in making classifications and the need to develop reliable scales to tap them. Other problems include the need to capture how behavior changes across age and across the episodes of the Strange Situation. Others will debate R. C. Fraley and S. J. Spieker's (2003) arguments concerning taxonomic status. However, whether taxa or not, Ainsworth's categories at the least have represented well the multidimensional space underlying attachment behavior in conditions of mild stress. Only when an alternative approach is demonstrated to predict (with equal power, in practice) the vast range of outcomes associated with Ainsworth's categories will it be a candidate for substitution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)