Basic numerical skills in children with mathematics learning disabilities: a comparison of symbolic vs non-symbolic number magnitude processing

Forty-five children with mathematics learning disabilities, with and without comorbid reading disabilities, were compared to 45 normally achieving peers in tasks assessing basic numerical skills. Children with mathematics disabilities were only impaired when comparing Arabic digits (i.e., symbolic number magnitude) but not when comparing collections (i.e., non-symbolic number magnitude). Moreover, they automatically processed number magnitude when comparing the physical size of Arabic digits in an Stroop paradigm adapted for processing speed differences. Finally, no evidence was found for differential patterns of performance between MD and MD/RD children in these tasks. These findings suggest that children with mathematics learning disabilities have difficulty in accessing number magnitude from symbols rather than in processing numerosity per se.     

Asymptotic learning of alphanumeric coding in autobiographical memory

Studies of autobiographical memory have shown that observed levels of incidental learning are often relatively low. Do low levels of retention result simply from a low learning rate, or is learning also asymptotic? To address this question, it is necessary to trace performance over a large number of learning opportunities, and this was carried out in the context of the recent development of widespread texting behaviour. It was found that memory for the alphanumeric layout of a phone improved as a function of sending approximately the first 500 texts, but then the improvement stopped. The incidence of memory error was incompatible with a simple power-law relation but was modelled closely by an asymptotic relation. It is suggested that this pattern reflects a movement towards automaticity in the primary task which progressively closes down the possibility that incidental learning can occur.     

Experience in integrative negotiations: What needs to be learned?

In this research we focus on the roles of experience and understanding in fostering integrative negotiation performance. We report on two experiments in which we distinguish between understanding opponents’ general priorities among issues versus understanding their specific gains for particular offers. Although experience enhanced integrative performance even in the absence of understanding, we found that understanding the specific gains had an incremental effect on performance. We conclude that while generally acknowledging opponents’ interests is not sufficient, the additional inferential step of assessing their specific gains throughout the negotiation process is advantageous.     

The influence of working memory on reading growth in subgroups of children with reading disabilities

This 3-year longitudinal study determined whether (a) subgroups of children with reading disabilities (RD) (children with RD only, children with both reading and arithmetic deficits, and low verbal IQ readers) and skilled readers varied in working memory (WM) and short-term memory (STM) growth and (b) whether growth in an executive system and/or a phonological storage system mediated growth in reading performance. A battery of memory and reading measures was administered to 84 children (11-17 years of age) across three testing waves spaced 1 year apart. The results showed that skilled readers yielded higher WM growth estimates than did the RD groups. No significant differentiation among subgroups of children with RD on growth measures emerged. Hierarchical linear modeling showed that WM (controlled attention), rather than STM (phonological loop), was related to growth in reading comprehension and reading fluency. The results support the notion that deficient growth in the executive component of WM underlies RD.     

The role of multiple-exemplar training and naming in establishing derived equivalence in an infant

The conditions under which symmetry and equivalence relations develop are still controversial. This paper reports three experiments that attempt to analyze the impact of multiple-exemplar training (MET) in receptive symmetry on the emergence of visual-visual equivalence relations with a very young child, Gloria. At the age of 15 months 24 days (15m24d), Gloria was tested for receptive symmetry and naming and showed no evidence of either repertoire. In the first experiment, MET in immediate and delayed receptive symmetrical responding or listener behavior (from object-sound to immediate and delayed sound-object selection) proceeded for one month with 10 different objects. This was followed, at 16m25d, by a second test conducted with six new objects. Gloria showed generalized receptive symmetry with a 3-hr delay; however no evidence of naming with new objects was found. Experiment 2 began at 17m with the aim of establishing derived visual-visual equivalence relations using a matching-to-sample format with two comparisons. Visual-visual equivalence responding emerged at 19m, although Gloria still had not shown evidence of naming. Experiment 3 (22m to 23m25d) used a three-comparison matching-to-sample procedure to establish visual-visual equivalence. Equivalence responding emerged as in Experiment 2, and naming emerged by the end of Experiment 3. Results are discussed in terms of the history of training in bidirectional relations responsible for the emergence of visual-visual equivalence relations and of their implications for current theories of stimulus equivalence.     

Differential contributions of dorsal vs. ventral hippocampus to auditory trace fear conditioning

The effect of excitotoxic lesions of dorsal vs. ventral hippocampus on the acquisition and expression of auditory trace fear conditioning was examined in two studies. In Experiment 1, animals received excitotoxic lesions of either the dorsal or ventral hippocampus or sham surgeries one week prior to conditioning, and were tested 24 h later. In Experiment 2, animals received excitotoxic lesions of either the dorsal or ventral hippocampus or sham surgeries 24 h after training, and were tested one week after surgery. Both pre- and post-training lesions of ventral hippocampus impaired the acquisition and expression, respectively, of auditory trace fear conditioning. Pre-training lesions of dorsal hippocampus had no effect on the acquisition of trace fear conditioning, while post-training lesions of dorsal hippocampus dramatically impaired expression during subsequent testing. Although in some cases animals with lesions of ventral hippocampus exhibited locomotor hyperactivity, it is unlikely that the pattern of observed deficits can be attributed to this effect. Collectively these data suggest that the dorsal and ventral hippocampus may contribute differentially to the mnemonic processes underlying fear trace conditioning.     

Post-training, but not post-reactivation, administration of amphetamine and anisomycin modulates Pavlovian conditioned approach

The psychostimulant, amphetamine (AMPH), and the protein synthesis inhibitor, anisomycin (ANI), have been shown to modulate the consolidation and reconsolidation of several types of learning. To determine whether Pavlovian conditioned approach (PCA) is modulated in a similar manner, we examined the effects of post-training and post-reactivation administration of both AMPH and ANI on memory for PCA. Male Long-Evans rats received PCA training sessions during which presentations of a CS+ were followed by sucrose delivery. AMPH (1 mg/kg, s.c.) injected immediately but not 6h after the first training session enhanced PCA behavior. ANI (150 mg/kg, s.c.) injected immediately but not 3h after the first training session impaired PCA behavior. This impairment was not due to the development of a conditioned taste aversion. To examine whether PCA can also be modulated by post-reactivation administration of AMPH and ANI, rats were given an injection of AMPH, ANI, or vehicle immediately after a memory reactivation session. Upon testing, the behavior of both the AMPH- and the ANI-treated rats was unaffected. This result remained consistent when the experiment was repeated with changes to various behavioral parameters (i.e., amount of training, length of memory reactivation). These findings indicate that AMPH and ANI act during the post-training but not the post-reactivation period to enhance and impair, respectively, the learning of PCA. This suggests that the consolidation of PCA can be modulated in a manner comparable to other types of learned associations, but once learned, the memory appears to be relatively robust and stable.     

Conflict between egg recognition and egg rejection decisions in common cuckoo (<Emphasis Type="Italic">Cuculus canorus</Emphasis>) hosts

Common cuckoos (Cuculus canorus) are obligate brood parasites, laying eggs into nests of small songbirds. The cuckoo hatchling evicts all eggs and young from a nest, eliminating hosts’ breeding success. Despite the consistently high costs of parasitism by common cuckoos, great reed warbler (Acrocephalus arundinaceus) hosts sometime accept and other times reject parasitic eggs. To explore the cognitive basis of this seemingly maladaptive variation in host responses, we documented differences in egg rejection rates within 1-day periods just before and during the egg-laying cycle across host nests. Hosts rejected cuckoo eggs at 28% of nests during the pre-egg-laying stage, but when cuckoos exchanged the first host egg with the parasite egg, rejections increased to 75%. Even later, when several host eggs remained in a nest after parasitism, rejection rate fell to 37.5%. Experimental parasitism with conspecific eggs on the first and second day of host laying showed a similar directional change in relative rejection rates, dropping from 35 to 0%. Mistakes in egg discrimination (ejection error and ejection cost) were observed mostly in the latter part of the laying cycle, mainly when nests contained 5–6 eggs. These correlational and experimental patterns of egg rejection support a cognitive process of egg discrimination through several shifts in hosts’ optimal acceptance thresholds of foreign eggs. The results are also consistent with the evolution of foreign egg rejection in the context of nest-sanitation (i.e. the removal of foreign objects). Our results suggest that common cuckoo hosts may recognize more eggs than they reject. This implies that the experience of the host with one or more of its own eggs in the clutch is a key factor in rejecting parasite eggs by allowing inspection and learning about their own clutch.     

不同运动经历人群的内隐序列学习能力

考察不同运动经历人群的内隐序列学习能力。被试为上海体育学院小球运动员和非运动员;实验结合PDP,采用序列学习任务,并测试操作智商与记忆广度。结果发现,运动员在15个组段上的平均反应时、内隐学习量、自动提取贡献率上显著大于非运动员;不同水平运动员在内隐学习量上差异显著。研究结论:运动员的内隐序列学习能力显著好于非运动员,与运动水平有关,与智商无显著相关;这种内隐序列学习能力可能是某种运动能力的表现形式。