The multiple-stimulus-without-replacement preference assessment tool and its predictive validity

This study demonstrates the use of two web-based programs, one to identify video preferences and the other to assess their reinforcing effects. We used the Multiple-Stimulus-Without-Replacement Preference Assessment Tool (MSWO PAT) to identify the video preference hierarchies of seven participants, ages 4–11 years old. We then used a customized reinforcer assessment program that arranged a concurrent-chains preparation with programmed conjugate schedules of reinforcement. Button presses emitted by participants modulated the quality (volume and opacity) of selected videos on a moment-to-moment basis, allowing us to identify the reinforcing effects of the videos in little time. The results showed that the preference assessment had predictive value for five of seven participants. We discuss the MSWO PAT, parameters that may affect the identification of preferences and the use of conjugate schedules to identify reinforcers.     

Response strength in extreme multiple schedules

Four pigeons were trained in a series of two-component multiple schedules. Reinforcers were scheduled with random-interval schedules. The ratio of arranged reinforcer rates in the two components was varied over 4 log units, a much wider range than previously studied. When performance appeared stable, prefeeding tests were conducted to assess resistance to change. Contrary to the generalized matching law, logarithms of response ratios in the two components were not a linear function of log reinforcer ratios, implying a failure of parameter invariance. Over a 2 log unit range, the function appeared linear and indicated undermatching, but in conditions with more extreme reinforcer ratios, approximate matching was observed. A model suggested by McLean (1991), originally for local contrast, predicts these changes in sensitivity to reinforcer ratios somewhat better than models by Herrnstein (1970) and by Williams and Wixted (1986). Prefeeding tests of resistance to change were conducted at each reinforcer ratio, and relative resistance to change was also a nonlinear function of log reinforcer ratios, again contrary to conclusions from previous work. Instead, the function suggests that resistance to change in a component may be determined partly by the rate of reinforcement and partly by the ratio of reinforcers to responses.     

Evaluating Open-Ended Parent Reports and Direct Preference Assessments to Identify Reinforcers for Young Children With Autism

Little research has evaluated open-ended parent reports to identify reinforcers for children with autism. This study evaluated open-ended parent reports and direct preference assessments for six young children with autism in home-based therapy. Results indicated little correspondence between parent reports and direct assessment assessments for all but one child. However, a follow-up reinforcer assessment with two children showed that the top ranked stimulus from both assessments functioned as reinforcers, with one child demonstrating higher levels of responding for the top ranked stimulus from the parent report. Results tentatively support open-ended parent reports to identify reinforcers for young children with autism.     

Dealing with Object Loss

The nature and outcome of working through an object loss depend on the proportions in which the lost relationship involved developmentally earlier (prestructural) and more advanced (poststructural), aspects. The two groups of elements are dealt with by entirely different methods, which are presented and discussed in this paper. For this purpose, some aspects of internalization are discussed and distinguishing a new form of internalization is proposed. The additional loss of objects following a major one are also briefly discussed.     

Children's and Adults' Acquisition of Spatial Information: Actual and Simulated Environmental Experience

Undergraduate students were presented with word pairs (e.g., egg-yolk) and were timed as they decided whether one word named part of the thing named by the other word. In Experiment 1, “no” responses to nonpart pairs (e.g., fish-flaps) were slowed by the similarity of the stimulus part (flaps) to a part that the stimulus object did possess (fins). This suggested that decisions were made by retrieving parts of the stimulus object from memory and comparing them to the stimulus part. Whereas the parts used as stimuli in Experiment 1 were nonspecific, belonging to several different types of object (e.g., wheel), those selected for Experiment 2 were specific to a single type of object (e.g., thumb). In Experiment 2, “no” responses to nonpart pairs (e.g., foot-thumb) were slowed by similarity of the stimulus object (foot) to an object that the stimulus part (thumb) belonged to (hand). This suggested that decisions were made by retrieving the object to which the stimulus part belonged and comparing it to the stimulus object. The results support a hybrid model of part-whole decisions that includes directed retrieval of relational knowledge from memory and a comparison process.     

Preference for fluent versus disfluent work schedules

Two studies were conducted that examined the preference of a student diagnosed with a brain injury. In Study 1, a preference assessment was followed by a three-choice concurrent-operants reinforcer assessment. Two choices resulted in access to preferred activities for completing work, and a third choice resulted in access to nothing (i.e., no activity). Unpredictably, the participant consistently chose the no-activity option. Study 2 examined why this student preferred work associated with no activity over preferred activities. Through a variety of concurrent-operants procedures, it was determined that she preferred fluent work followed by reinforcers rather than work that was broken up by access to preferred activities. Implications for research on preference are discussed.     

Preference and reinforcer efficacy of high‐ and low‐tech items: A comparison of item type and duration of access

This study examined the interactions of stimulus type (high‐ vs. low‐tech) and magnitude (duration of access) on preference and reinforcer efficacy. Two preference assessments were conducted to identify highly preferred high‐tech and low‐tech items for each participant. A subsequent assessment examined preference for those items when provided at 30‐s and 600‐s durations. We then evaluated reinforcer efficacy for those same items when provided for a range of durations using progressive‐ratio schedules. Results suggested item type and access duration interacted to influence preference and reinforcer efficacy. Participants preferred high‐tech items at longer durations of access and engaged in more responding when the high‐tech item was provided for long durations, but these patterns were reversed for the low‐tech item. In addition, participants engaged in less responding when the high‐tech item was provided for short durations and when the low‐tech item was provided for long durations.     

RISKY CHOICE IN PIGEONS AND HUMANS: A CROSS‐SPECIES COMPARISON

Pigeon and human subjects were given repeated choices between variable and adjusting delays to token reinforcement that titrated in relation to a subject's recent choice patterns. Indifference curves were generated under two different procedures: immediate exchange, in which a token earned during each trial was exchanged immediately for access to the terminal reinforcer (food for pigeons, video clips for humans), and delayed exchange, in which tokens accumulated and were exchanged after 11 trials. The former was designed as an analogue of procedures typically used with nonhuman subjects, the latter as an analogue to procedures typically used with human participants. Under both procedure types, different variable‐delay schedules were manipulated systematically across conditions in ways that altered the reinforcer immediacy of the risky option. Under immediate‐exchange conditions, both humans and pigeons consistently preferred the variable delay, and indifference points were generally ordered in relation to relative reinforcer immediacies. Such risk sensitivity was greatly reduced under delayed‐exchange conditions. Choice and trial‐initiation response latencies varied directly with indifference points, suggesting that local analyses may provide useful ancillary measures of reinforcer value. On the whole, the results indicate that modifying procedural features brings choices of pigeons and humans into better accord, and that human—nonhuman differences on risky choice procedures reported in the literature may be at least partly a product of procedural differences.