Are there lexicons?

Many models of the processing of printed or spoken words or objects or faces propose that systems of local representations of the forms of such stimuli—lexicons—exist. This is denied by partisans of the distributed-representation connectionist approach to cognitive modelling. An experimental paradigm of key theoretical importance here is lexical decision and its analogue in the domain of objects, object decision. How does each theoretical camp account for our ability to perform these two tasks? The localists say that the tasks are done by matching or failing to match a stimulus to a local representation in a lexicon. Advocates of distributed representations often do not seek to explain these two tasks; however, when they do, they propose that patterns of activation evoked in a semantic system can be used to discriminate between words and nonwords, or between real objects and false objects. Therefore the distributed-representation account of lexical and object decision tasks predicts that performance on these tasks can never be normal in patients with an impaired semantic system, nor in patients who cannot access semantics normally from the stimulus domain being tested. However, numerous such patients have been reported in the literature, indicating that semantic access is not needed for normal performance on these tasks. Such results support the localist form of modelling rather than the distributed-representation approach.     

358,534 nonwords: The ARC Nonword Database

The authors present a model of the phonotactic and orthographic constraints of Australian and Standard Southern British English monosyllables. This model is used as the basis for a web-based psycholinguistic resource, the ARC Nonword Database, which contains 358,534 monosyllabic nonwords--48,534 pseudohomophones and 310,000 non-pseudohomophonic nonwords. Items can be selected from the ARC Nonword Database on the basis of a wide variety of properties known or suspected to be of theoretical importance for the investigation of reading.     

Whammies and double whammies: The effect of length on nonword reading

In the work presented here, the length effect in nonword reading aloud was investigated in order to assess whether that effect is driven by the number of letters in a string or by the number of graphemes in a string. Simulation work with the Dual-Route Cascaded (DRC) model (e.g., Coltheart, Curtis, Atkins, & Haller, 1993; Coltheart & Rastle, 1994) uncovered a surprising finding regarding the length effect; the same result was obtained in an experiment with human subjects. The results are discussed in terms of the DRC model, with particular reference to serial processing and interphoneme inhibition, two properties critical to understanding the effect reported here.     

Obedience as a function of experimenter competence

The purpose of this study was to investigate obedience to an E’s commands as a function of E competency. Based upon Orne’s (1962, 1969) discussion of the demand characteristics inherent in the typical aggression study, it was hypothesized that E incompetence would decrease S obedience. Competence was manipulated by: (1) presenting some Ss with a nervous and inexperienced E, and (2)“accidentally” killing the victim (a rat) midway through the experiment. Thirty-two undergraduate female Ss participated in the experiment—supposedly a study on the physiological effects of stress. Obedi6nce was operationalized as the difference, in simple reaction time, between trials on which Ss were told that their response might result in shock to the rat and trials on which they were told that their response might save the rat from shock. Significant differences in obedience were obtained between competent and incompetent E conditions, and a significant “kill” effect was found in the competent E conditidn. The results of this study suggested that the extreme acts of obedience observed in the laboratory (e.g., Milgram, 1963) occur only when E is perceived as competent. This finding imposes limits on the generalizability of laboratory studies of obedience.     

The efficacy of “right” as a function of its relationship with reinforcement

The effects of the relationship between the presentation of a verbal stimulus (“right”) and an established reinforcer (M&Ms) on the reinforcement efficacy of the verbal stimulus was tested with three groups of retarded boys. Blocks of training and test trials alternated. During training of the Discriminative Group, “right” reliably preceded candy. For the Contiguous Group, “right” accompanied candy, and for the Random Group “right” and candy were programmed independently. “Right” promoted learning in the Discriminative Group but did not in the latter two groups. The results support Cairns' analysis of the often found failure of approval to be an effective reinforcer in laboratory tasks.