An Analysis of Item Response Theory and Rasch Models Based on the Most Probable Distribution Method

The most probable distribution method is applied to derive the logistic model as the distribution accounting for the maximum number of possible outcomes in a dichotomous test while introducing latent traits and item characteristics as constraints to the system. The item response theory logistic models, with a particular focus on the one-parameter logistic model, or Rasch model, and their properties and assumptions, are discussed for both infinite and finite populations.     

Promoting Functional Ambulation with People with Blindness and Multiple Disabilities

An intervention package comprising auditory cues, physical prompts preceded by vibratory (anticipatory) stimuli, and reinforcement was used to promote ambulation to target places with 2 men with total blindness, profound intellectual disability, and behavioural problems. Data showed that both men acquired successful ambulation to the target places, becoming almost totally independent of the physical prompts. Implications of the findings are discussed.     

Use of Anticipatory Cues to Reduce Dependence on Physical Prompts by an Adolescent with Multiple Disabilities

Anticipatory cues (vibratory stimulation activated through remote control) were used in this study to help an adolescent with multiple disabilities to reduce his dependence on the caregiver's physical prompts. The results show that anticipatory cues were effective in helping the adolescent perform practical daily responses independently of physical prompts. Towards the end of the study, the adolescent could also perform increasingly independently of the anticipatory cues. Implications of the findings are discussed.     

Using paired-choice assessment to identify variables maintaining sleep problems in a child with severe disabilities

In this study, we used a paired-choice assessment protocol to identify the relative reinforcing value of stimuli and activities for a child with severe disabilities when she failed to settle to sleep at night. The results of this assessment indicated that the child preferred the mother's attention relative to other activities presented. Assessment results were incorporated into an intervention, that produced a reduction in sleep disturbance that was maintained at a 12-month follow up.     

A microswitch program including words and choice opportunities for students with multiple disabilities

Two students with multiple disabilities were provided with two or three request microswitches and one choice microswitch. Activation of a request microswitch triggered the verbal announcement of one of the stimulus events related to it. The student could choose such an event through the choice microswitch or bypass it. The request microswitches were introduced individually and made available simultaneously by the end of the intervention and the postintervention period. Analysis showed that both students learned to use the microswitches. Transfer of the microswitch program into the students' home was very successful with one student and presented some difficulties with the other. Implications of the findings and new possible developments were discussed.     

Multiple microswitches for persons with multiple disabilities: a basic procedure to examine the persons' choice behavior

This study examined a basic choice-analysis procedure to clarify choice between two responses and related stimuli by five persons with multiple disabilities ages 17.1 to 50.2 yr. The procedure was based on reversing the links between responses and stimuli to assess whether the stimuli accounted for differences in response levels. When this was not the case, the procedure added extra stimuli for the less preferred response to judge whether such an increase would compensate for the apparent disadvantage of that response, e.g., its higher physical cost. Analysis showed that the choice of three of the five participants seemed motivated by the stimuli following the responses. The choice of the other two persons seemed related to a preference for one of the responses which was partially or largely modified when extra stimuli were added.     

Teaching 'Yes' and 'No' responses to children with multiple disabilities through a program including microswitches linked to a vocal output device

The present study introduced two children (a boy and a girl of 9.2 and 12.3 yr. of age, respectively, with multiple disabilities) to an intervention program for establishing Yes and No responses in relation to preferred and nonpreferred stimuli and assessed the acquisition and generalization of those responses. The program involved the use of microswitches, which monitored the nonverbal Yes and No responses performed by the children and ensured that these responses produced the matching verbal utterances via a vocal output device. Analysis showed children acquired Yes and No responses in relation to the stimuli used for the intervention and, to a comparable degree, to the stimuli used for generalization checks as well. An interview of 30 educational staff of a center for persons with multiple disabilities indicated that they considered the presence of Yes and No verbal utterances preferable to the absence of such utterances, and thought that the utterances could be helpful for the children's response acquisition and would be useful and pleasing for staff and parents. General implications of the findings were discussed.     

Writing program with word prediction for a young man with multiple disabilities: a preliminary assessment

This study assessed a writing program with word prediction, which completed the writing of a word and spoke it out only when there was certainty that such a word was the correct one. The assessment was carried out with a young man with multiple disabilities, who typically used a word-processing program without word prediction. The two programs were compared on the time required by the participant for writing general sentences, through a social validation assessment, and eventually a check on the participant's preference. Analysis showed the program with word prediction was significantly more effective in terms of the writing time, which was halved, and was deemed preferable by 40 raters (psychology students) involved in the social validation assessment and by the participant himself. Implications of the findings are discussed.     

A brief account of statistical tests for single-case research with persons with developmental disabilities

Education and rehabilitation research with persons with developmental disabilities is often based on single-case designs (with small numbers of ordinal data points collected at irregular intervals) and relies upon graphic display and visual inspection of the data. This paper (a) provides a brief account of some statistical tests, which may serve to supplement the visual inspection process and (b) underlines some of their strengths and limitations to help education and rehabilitation personnel make a reasonable choice among them.     

Multinational data show that conspiracy beliefs are associated with the perception (and reality) of poor national economic performance

While a great deal is known about the individual difference factors associated with conspiracy beliefs, much less is known about the country-level factors that shape people's willingness to believe conspiracy theories. In the current article we discuss the possibility that willingness to believe conspiracy theories might be shaped by the perception (and reality) of poor economic performance at the national level. To test this notion, we surveyed 6723 participants from 36 countries. In line with predictions, propensity to believe conspiracy theories was negatively associated with perceptions of current and future national economic vitality. Furthermore, countries with higher GDP per capita tended to have lower belief in conspiracy theories. The data suggest that conspiracy beliefs are not just caused by intrapsychic factors but are also shaped by difficult economic circumstances for which distrust might have a rational basis.