Categorical perception effects reflect differences in typicality on within-category trials

Many studies have shown better discrimination of two stimuli that cross a category boundary than of two stimuli belonging to the same category. This finding, known as categorical perception, is generally assumed to reflect consistently good performance on cross-category trials, relative to within-category trials. However, Roberson, D., Damjanovic, L., and Pilling, M. (Memory & Cognition, 35, 1814-1829, 2007) revealed that performance on within-category pairs of morphed facial expressions matched performance on cross-category trials when the target was a good exemplar of its category. Here, we investigate the generality of that finding by conducting new analyses of data from a series of studies of categorical perception in facial identity and color domains with speakers of different languages. Consistent with Roberson et al. (2007), the new analyses demonstrate that performance for central targets on within-category trials is as good as performance on cross-category trials. Participants perform badly on within-category items only when the target is closer to the category boundary than is the distractor. These results provide no support for the view that categorical perception is associated with increased perceptual sensitivity at category boundaries.     

A method for identifying satiation versus extinction effects under noncontingent reinforcement schedules

We evaluated one method for determining whether response suppression under noncontingent reinforcement (NCR) is a function of satiation or extinction. Three individuals with developmental disabilities who engaged in self-injurious behavior (SIB) or aggression participated. Results of functional analyses indicated that their problem behavior was maintained by social-positive reinforcement. NCR procedures, individualized for each participant, were implemented in a multiple baseline across subjects design and were associated with decreases in all participants' problem behavior. Identification of the mechanism by which NCR produced these effects was based on examination of cumulative records showing response patterns during and immediately following each NCR session. Satiation during NCR should lead to a temporary increase in responding during the post-NCR (extinction) period due to a transition from the availability to the unavailability of reinforcement (satiation to deprivation). Alternatively, extinction during NCR should reveal no increase in responding during the extinction period because the contingency for the problem behavior would remain unchanged and the transition from satiation to deprivation conditions would be irrelevant. Results suggested that the operative mechanisms of NCR were idiosyncratic across the 3 participants and appeared to change during treatment for 1 of the participants.     

Response-restriction analysis: I. Assessment of activity preferences

We used procedures based on response-restriction (RR) analysis to assess vocational and leisure activity preferences for 3 adults with developmental disabilities. To increase the efficiency of the analysis relative to that reported in previous research, we used criteria that allowed activities to be restricted at the earliest point at which a preference could be determined. Results obtained across two consecutive RR assessments showed some variability in overall preference rankings but a high degree of consistency for highly ranked items. Finally, we compared results of the RR assessment with those of an extended free-operant assessment and found that the RR assessment yielded (a) more differentiated patterns of preference and (b) more complete information about engagement with all of the target activities.     

Rousseau's three revolutions

Rousseau's relation to the French Revolution – and in particular his status as the Revolution's precursor or predictor or progenitor – has been often examined. Yet almost no sustained attention has been given to what is arguably Rousseau's most significant and explicit statement on revolution and its role in civilization's development. This paper calls attention to this statement and argues for its key significance on three fronts: first, for how it organizes Rousseau's conjectural history of civilization in the second Discourse; second, for the insight it offers into the processes of Rousseau's pre‐Hegelian philosophy of history; and third, for the normative political implications of its standard for measuring the relative progress of inequality in a given society at a given time.     

Mand compliance as a contingency controlling problem behavior: A systematic review

Bowman et al. (1997) described a dynamic contingency in which severe problem behavior was evoked by adult noncompliance with a variety of child mands, which occurred at high rates, and was reinforced by adult compliance with subsequent mands. They discovered this phenomenon with 2 children for whom standard functional analyses were inconclusive. In recent years, similar contingencies have been shown to influence problem behavior, but the manner in which they have been arranged and described has varied across studies. The purpose of this literature review is to (a) describe contingencies involving mand compliance and the circumstances under which they have been evaluated, (b) summarize procedural variations in analysis and treatment, and (c) discuss what is known and yet to be discovered about the contingency as it relates to problem behavior. Future research focused on improving technology for analyzing and treating problem behavior suspected to be sensitive to mand compliance is discussed.     

Does teaching an omnibus mand preclude the development of specifying mands?

When problem behavior is controlled by a synthesized reinforcement contingency, a simple omnibus mand that yields access to all reinforcers simultaneously has been shown to effectively replace problem behavior. The question arises as to whether teaching an omnibus mand will preclude the acquisition of specifying mands for each of the combined reinforcers. In this study, after 3 students diagnosed with autism acquired an omnibus mand (“My way, please”) that yielded all identified reinforcers simultaneously, specifying mands (e.g., “All done,” “May I have my toys?” “Play with me”) were taught to yield each individual reinforcer (e.g., escape, tangibles, attention). Problem behavior was immediately eliminated for all children, and the omnibus mand was acquired quickly. Teaching an omnibus mand did not preclude acquisition of specifying mands for any learner and instead allowed for the acquisition of specifying mands once problem behavior had been effectively reduced.     

An evaluation of multiple‐schedule variations to reduce high‐rate requests in the picture exchange communication system

Using procedures similar to those of Tiger, Hanley, and Heal (2006), we compared two multiple‐schedule variations (S+/S– and S+ only) to treat high‐rate requests for edible items in the Picture Exchange Communication System (PECS). Two individuals with autism participated, after they showed persistent requests for edible items after PECS training. Stimulus control was achieved only with the multiple schedule that involved presentation of a discriminative stimulus during reinforcement components and its removal during extinction components (S+ only). Discriminated requests were maintained for the 1 participant who experienced schedule thinning.     

MERLOT: A faculty-focused Web site of educational resources

The Multimedia Educational Resource for Learning and Online Teaching (MERLOT) is a community of academic institutions, professional discipline organizations, and individual people building a collection of Web-based teaching and learning resources where faculty can easily find peer-reviewed materials for use in their classes. The MERLOT project is currently supported by 23 systems and institutions of higher education and by the National Science Foundation. MERLOT is developing collections of learning materials from many academic disciplines, including psychology.     

A method for describing preschoolers' activity preferences

We designed a series of analyses to develop a measurement system capable of simultaneously recording the free-play patterns of 20 children in a preschool classroom. Study 1 determined the intermittency with which the location and engagement of each child could be momentarily observed before the accuracy of the measurement was compromised. Results showed that intervals up to 120 s introduced less than 10% measurement error. Study 2 determined the extent of agreement between two observers who simultaneously collected data for 20 children using 30-, 60-, 90-, and 120-s momentary time sampling (MTS) intervals. The three larger intervals resulted in high levels of interobserver agreement (above 90%), whereas the 30-s interval resulted in unacceptably low levels of agreement (less than 80%). By allowing observers to select from among the different MTS intervals via a datasheet array and then collect data with the chosen system, Study 3 determined observers' preferences for the remaining MTS intervals. Both data collectors preferred the 90-s MTS procedure. The sensitivity of the 90-s MTS procedure, which was shown to be accurate, reliable, and preferred, was then demonstrated by its use to describe activity preferences of a classroom of children in Study 4. This system identified high- and low-preference activities for individual children and revealed interesting patterns of response allocation by the group.     

The effects of reinforcer pairing and fading on preschoolers' snack selections

The effects of reinforcement pairing and fading on preschoolers' snack selections were evaluated in a multiple baseline design. Baseline preferences for snack options were assessed via repeated paired-item preference assessments. Edible, social, and activity-based reinforcers were then exclusively paired with a less preferred snack option. Once the snack paired with reinforcement was selected most frequently, the three types of reinforcement were systematically faded. Frequent selections of the previously less preferred snack option were produced with paired reinforcement, but were disrupted for all children as the paired reinforcement was reduced to low levels. These data showed that paired reinforcement was initially effective in increasing preference for the originally less preferred snack options, but more permanent changes in the value of the snack options were not achieved. Conditions for producing persistent changes in children's snack choices are discussed.