Effects of stimulus variation on the reinforcing capability of nonpreferred stimuli

We examined the effects of stimulus (reinforcer) variation in several different contexts. In Study 1, we identified high-quality (HQ) and low-quality (LQ) stimuli based on results of a paired-stimulus assessment and examined their effects when available under concurrent-reinforcement schedules for 8 participants. No participants showed preference for the LQ stimuli when compared singly or in a varied arrangement to the HQ stimulus. In Study 2, we identified nonpreferred (NP) stimuli based on results of a single-stimulus assessment and examined their effects when available under single-reinforcement schedules for 3 participants. Results of Study 2 were mixed. One participant's data indicated that the varied presentation of NP stimuli produced a modest improvement in performance over that observed when the stimuli were presented singly. By contrast, a second participant's data showed no facilitative effect for the varied delivery of NP stimuli and that the inclusion of an HQ stimulus in the varied arrangement obscured the reinforcing effects of the HQ stimulus. The 3rd participant's data showed no effect for the varied delivery of NP stimuli but an apparent facilitative effect when an HQ stimulus was included in the varied arrangement, which was attributable solely to the presence of the HQ stimulus.     

Behavioral treatment of children with phonological disorder: the efficacy of vocal imitation and sufficient-response-exemplar training

This study examined whether sufficient-response-exemplar training of vocal imitation would result in improved articulation in children with phonological disorder, and whether improved articulation established in the context of vocal imitation would transfer to other verbal classes such as object naming and conversational speech. Participant 1 was 6 years old and attended first grade in a regular public school. Participant 2 was 5 years 4 months old and attended a public kindergarten. Both participants had normal hearing and no additional handicaps. A multiple baseline design across behaviors (target sounds or blends) was employed to examine whether the vocal imitation training resulted in improved articulation. Results showed that both participants improved articulation once training was implemented, and that the improved articulation transferred from vocal imitation to more natural speech such as object naming and conversational speech. Improvement established during training was maintained posttraining and at a 6-month follow-up.     

Silent letters and phonological priming

Many written English words contain silent letters. Omitting them produces nonwords pronounced identically to the original words, for example, SALM for PSALM and COLUM for COLUMN. We report two naming and two lexical decision experiments in which targets of 4–11 letters followed primes exposed for 100 ms in mask-prime-mask-target sequences. Priming in SALM-psalm and COLUM-column pairs exceeded priming in orthographic control pairs such as ASTA-pasta and COUSI-cousin, pairs in which pronounced letters are omitted to form the primes. SALM and COLUM, however, were less effective primes than PSALM and COLUMN. Results were discussed in terms of the phonological coherence hypothesis, the role of orthographic codes in filtering phonologically activated representations, and graphemes as reading units.     

Choice in a variable environment: effects of unequal reinforcer distributions

Six pigeons were trained in a procedure in which sessions included seven unsignaled components, each offering two pecking keys, and each providing a potentially different reinforcer ratio between the two keys. Across conditions, various combinations of reinforcer ratios and reinforcer-magnitude ratios were used to create unequal reinforcer distributions between the two alternatives when averaged across a session. The results extended previous research using the same basic procedure that had included only reinforcer distributions symmetrical around 1:1. Data analyses suggested that the variables controlling choice operated at a number of levels: First, individual reinforcers had local effects on choice; second, sequences of successive reinforcers obtained at the same alternative (continuations) had cumulative effects; and, third, when these sequences themselves occurred with greater frequency, their effects further cumulated. A reinforcer obtained at the other alternative following a sequence of continuations (a discontinuation) had a large effect and apparently reset choice to levels approximating the sessional reinforcer ratio.     

Rhythmic information in working memory: effects of concurrent articulation on reproduction of rhythms

The study addressed a previously neglected issue in the concept of working memory, namely whether or not rhythmical information is coded and maintained in a phonological loop. Thirty subjects engaged in a task which required them to reproduce the temporal sequence of rhythm. The results showed that the reproduction of rhythm was dramatically reduced by a concurrent articulation, and that the deterioration of rhythm reproduction was larger than that obtained with a concurrent spatial task which would not diminish the activity of the phonological loop directly. An articulatory component of the working memory apparently plays an important role in memorizing rhythms. Furthermore, the sparse-dense rhythm (a pattern which started with sparse temporal structure and ended with a dense one) allowed better memorization than a dense-sparse pattern. The sources of the sparse-dense superiority effect are discussed in terms of the working memory for rhythmic information.     

Why is learning to read a hard task for some children?

In this brief review of some of my research on reading disability, I argue that a child’s development into literacy has two major ontogenetic roots, one involving early informal literacy socialization and one related to phonological awareness. Although failure in reading acquisition might be a question of cultural deprivation, the dynamic interaction between genetic dispositions and environment must be acknowledged, especially in a society providing rich sources of print exposure. The crucial transition in literacy development involves a step from implicit to explicit control of the phonemic units of language. When the cipher of the alphabetic system is understood the child is equipped with a powerful instrument for self teaching. A primary source of reading disability is then related to problems of segmenting the speech stream into phonemic units. The poor functioning of the phonological module seems to be a circumscribed deficit not related to general cognitive ability. The causal and reciprocal relationship between phonological awareness and learning to read has been demonstrated in my research over 20 years. Some of these studies are briefly reviewed in this article. The preventive and remedial implications of the findings are rather obvious.     

THE APPLICATION OF NATURALISTIC CONVERSATION TRAINING TO SPEECH PRODUCTION IN CHILDREN WITH SPEECH DISABILITIES

The purpose of this experiment was to test the effectiveness of including speech production into naturalistic conversation training for 2 children with speech production disabilities. A multiple baseline design across behaviors (target phonemes) and across subjects (for the same phoneme) indicated that naturalistic conversation training resulted in improved spontaneous speech production. The implications of these findings are discussed relative to existing models of speech production training and other aspects of communication disorders.     

连绵词语音类似的启动效应

研究采用快速启动范型考察了视觉连绵词加工中语音的自动激活.两个实验发现,无论是首字同音还是尾字同音启动都可以促进对连绵词的命名反应,且基本不受目标词熟悉性(词频高低)及真假词的影响.可以推断,至少在连绵词--这种单词素词的词汇通达中存在语音的自动激活,这种语音的激活可以说是前词的装配与词水平上的改变.     

非平衡中-英双语者言语产生中非目标语言的语音激活

采用改造的图片命名启动范式考察非平衡中-英双语者在言语产生中非目标语言的语音激活范围。实验1探讨在准备用汉语命名图片后,英语词汇的语音激活。结果发现,英语语音一致词的命名反应快于语音相关词和语音无关词,且语音相关词的命名反应快于语音无关词,说明在一语的产生过程中,二语对等词和相关词的语音都得到了激活。实验2探讨在准备用英语命名图片后,汉语词汇的语音激活。结果发现,汉语语音一致词的命名反应快于语音相关词和语音无关词,而语音相关词与语音无关词之间的命名反应没有显著差异,说明在二语的产生过程中,只有一语对等词的语音得到了激活。总结果表明,非平衡中-英双语者使用目标语言时,非目标语言的语音也可以得到激活,并且激活范围可能受非目标语言熟练水平的影响。     

言语产生中的词长效应

采用图片命名方法考察言语产生中的词长效应,并进而分析语音计划的单位和序列性。选取能同时用单音节(如“羊”)和双音节(“山羊”)命名的图片作刺激材料,发现双音节命名明显慢于单音节命名,这种效应既表现在首音节型(如“花”与“花朵”),也表现在尾音节型(如“羊”与“山羊”)刺激材料上。研究结果支持语音编码从左到右、系列提取和双音节词的词音计划单位大于单音节词的观点。该文还对图片命名中的频率效应进行了事后分析。