Stimulus timing by people with Parkinson's disease

Previous literature suggests that Parkinson’s disease is marked by deficits in timed behaviour. However, the majority of studies of central timing mechanisms in patients with Parkinson’s disease have used timing tasks with a motor component. Since the motor abnormalities are a defining feature of the condition, the status of timing in Parkinson’s disease remains uncertain. Data are reported from patients with mild to moderate Parkinson’s disease (both on and off medication) and age- and IQ-matched controls on a range of stimulus timing tasks without counting. Tasks used were temporal generalization, bisection, threshold determination, verbal estimation, and a memory for duration task. Performance of patients was generally “normal” on all tasks, but significant differences from performance of controls were found on the memory for duration task. Among the “normal” effects noted were arithmetic mean bisection, asymmetric temporal generalization gradients, and subjective shortening on the memory for duration task. The results suggest (a) that some previous reports of timing “deficits” in Parkinson’s patients were possibly due to the use of tasks requiring a timed manual response and (b) small differences between patients and controls may be found on tasks where two stimuli are presented on each trial, whether patients are on medication or off it.     

Teaching Phoneme Segmenting and Blending as Critical Early Literacy Skills: An Experimental Analysis of Minimal Textual Repertoires

The purpose of the current study was to examine blending and segmenting of phonemes as an instance of small, textual response classes that students learn to combine to produce whole word reading. Using an A/B/A/B design, a phoneme segmenting and blending condition that included differential reinforcement for response classes at the level of phonemes was compared to a control condition which was equated for differential reinforcement of reading words and opportunities to respond. The critical difference between conditions was the size of the responses that were brought under stimulus control (phonemes versus whole words). Findings clearly supported the superiority of the phoneme blending treatment condition over the control condition in producing generalized increases in word reading. The results are discussed in terms of the behavioral mechanisms that govern early literacy behaviors and the essential role that targeting measured increases in academic responses plays in furthering our understanding of how to improve the analysis and instruction of students who need to learn these important skills.     

Sitting on the word “chair”: Behavioral support, contextual cues, and the literal use of symbols

Recent work from an embodied-cognition perspective suggests that symbolic understanding involves bodily actions. Indeed, laboratory evidence and cultural phenomena such as magic rituals and symbolic aggression show that the behaviors evoked by a word and its referent can be quite similar to each other. In other circumstances, however, words and objects fail to display the expected degree of functional equivalence: Although we regularly sit on chairs, for example, we normally do not sit on the word “chair.” In two experiments we evaluated whether functional equivalence between word and object depended on behavioral support and contextual stimuli, as suggested by some Pavlovian views of symbolic performance. Children spent more or less time seated on a token of the word “chair,” depending on supports for sitting and background stimuli. This study may help to understand the determinants of response frequency in symbolic understanding.     

Programming a randomized dependent group contingency and common stimuli to promote durable behavior change

Low levels of academic engagement may impede students’ acquisition of skills. Intervening on student behavior using group contingencies may be a feasible way to increase academic engagement during group instruction. The current study examined the effect of a randomized dependent group contingency on levels of academic engagement for second‐grade participants receiving small‐group reading and writing instruction. The results showed that a randomized dependent group contingency increased the academic engagement of primary participants and several of the other participants during small‐group instruction. The findings also showed that high levels of academic engagement were maintained when common stimuli were present and the dependent group contingency was withdrawn.     

Teaching children with autism to request help with difficult tasks

We taught three children diagnosed with autism spectrum disorder to request help using an interrupted chain procedure during which we manipulated task materials such that the child was either incapable or capable of independently completing a link of a behavior chain. We initially observed undesirable generalization of requests for help during capable trials when teaching was introduced during incapable trials for two participants and to a lesser extent for the third participant. However, with repeated exposure to differential prompting and reinforcement across incapable and capable trials, differential responding was observed across EO‐present and EO‐absent trials for all three participants during both teaching sets and one generalization set that was never exposed to teaching procedures. These findings suggest that it is important to consider the antecedent conditions under which the response should occur when teaching children to request help.     

积极情绪对条件性恐惧泛化的抑制作用

恐惧的过度泛化是焦虑障碍的核心症状之一,表现为患者对与原危险刺激极不相似的安全刺激也产生恐惧反应。本研究采用经典条件恐惧范式,以US主观预期、回溯性恐惧评定、回溯性效价评定和皮电反应作为恐惧反应的指标,通过"最好自我"训练来诱发被试的积极情绪,考察了恐惧习得后的积极情绪对于恐惧泛化的影响。本研究发现,积极情绪能有效地抑制条件性恐惧的泛化,增强被试对安全信号的学习,并对消退后的恐惧重建现象起到预防作用。研究同时显示,恐惧泛化在主观评定指标和生理指标间出现了分离,这表明积极情绪对恐惧泛化的抑制作用是一个综合的过程,可能涉及到不同的作用机制。本研究结果提示可以通过诱发积极情绪,抑制条件性恐惧的泛化,对临床干预有一定的启发意义。     

Jules Verne's Journey to the Centre of the Earth: The Secret of Counterdepressive Narratives1

The author interprets Jules Verne's Journey to the centre of the Earth with the help of Matte Blanco's theoretical framework, which describes the principle of symmetry and the principle of generalization. The fi rst states that, from the moment an element or a proposition becomes conscious, it coexists in the unconscious with its symmetrically opposite form. The second refers to the confusion of elements once they have been apprehended by thought as containing a common point; they are put into larger and larger groups which merge into an indivisible whole. Verne's novel is built on paired elements which become symmetrized (e.g. distinct minerals vs molten lava; scientifi c rationality vs madness; the living vs the dead, etc.). These elements in turn become confused with one another, thanks largely to the novel's atmosphere of oral incorporation. This allows the fusion between subject and object, and, in particular, between the orphaned hero and his dead (Earth) mother. The novel's narrative evolution through three stages (separation, fusion and de‐fusion, which are paralleled by rational, irrational and rational thought) can thus be understood as a mourning process. Similar processes can be found in other literary works.     

Intertrial pellets influence the acquisition and expression of timed appetitive responding in rats

Two experiments examined temporally based changes in the conditioned magazine-entries of rats when a target food pellet arrived at a fixed time before the termination of a conditioned stimulus. Both experiments found that increasing the rate of intertrial pellets systematically interfered with the rate of acquisition. When intertrial pellets were featured in acquisition, their omission on test trials also resulted in a very poorly expressed conditioned response. On test trials preceded by intertrial pellets, however, peak times in groups trained with intertrial pellets were shifted in a rightward direction under a long but not short interstimulus interval. This rightward shift was accompanied by a smaller standard deviation. Our key findings are best accommodated by real-time associative models.     

Generalization gradients in a navigation task with rats

In two experiments in a Morris pool, rats were trained to find a hidden platform which was located in a specific position in relation to two objects, B and F, which were presented together, one in front of the other. One object, B, was just above the platform (a beacon for the platform, the critical object) while the second object, F, was above the edge of the pool (the frame of reference). Then the rats received test trials, without the platform, in which B was presented in different positions in relation to F (i.e., in relation to its original position). In the two experiments the test results showed a generalization gradient as a function of the relative distance of the two objects: more time searching in the B segment, where the platform should have been, when B was in the original position (i.e., in front of F), which decreased symmetrically with distance of B from F. The present experiments show for the first time generalization gradients with rats across spatial locations when working with a navigation task.     

Spontaneous Response Generalization During Whole Word Instruction: Reading to Spell and Spelling to Read

The bulk of the existing literature emphasizes the use of phonemic/phonetic based instruction to enhance generalization between reading and written language. However, phonetically irregular words are common in English and may require the use of whole word approaches. This study examined generalization between from reading to spelling and from spelling to reading following whole word based instruction using a delayed prompt procedure. The total instructional time was equated across conditions. Students exhibited substantial but incomplete generalization with the degree of generalization varying somewhat across responses and students. The most striking finding was that oral spelling instruction in which the printed word was neither presented nor produced resulted in substantial generalization to reading. These data illustrate a model for examining response generalization in instructional contexts.