Student Procrastination on an E-learning Platform: From Individual Discounting to Group Behavior.

Most applied research on delay discounting has focused on substance use disorders, eating, or gambling. In comparison, the issue of procrastination has received little interest from quantitative behavior analysts. In the present study, conducted on an e-learning platform, a group of 295 psychology students completed a series of four tests. The students could choose the day and hour on which they completed the tests, the deadline for each test being separated from the previous one by a period of 30 days. Most students completed the test in the last days before the deadline. The group response profile across days, reminiscent of fixed-interval scalloping, was well described formally by a hyperbola, replicating previous results by Howell et al. (2006). Also, the students' individual degree of procrastination showed stability across tests, in accordance with the notion of discounting as a persistent behavioral trait, and was negatively correlated with the students' grades. Finally, the shape of the scallop observed at the group level was consistent with a lognormal density of individual degrees of impulsivity, as measured by people's delay-discounting parameter.

The effects of stimulus pairings on autistic children's vocalizations: Comparing forward and backward pairings.

In a procedure known as stimulus-stimulus pairing (Yoon and Bennett, 2000), the experimenter pairs a target sound (e.g., "bah") with a child's preferred item (e.g., a toy). Even though the stimulus pairings proceed independently of the child's behavior, this procedure has proved capable of increasing imitation of the target sound in developmentally delayed children (Shillingsburg et al., 2015). The underlying behavioral processes remain poorly known, however, and few systematic variations of the basic procedure have been published. In the present experiment, with autistic children as participants, (a) we compared the effects of forward versus backward pairings on the imitation of target sounds, and (b) we evaluated formally the relation between the children's preexisting verbal repertoires and the efficacy of the pairing procedure. As is often reported in the Pavlovian literature, backward pairings promoted lower levels of conditional responding than forward pairings. Also, we found a negative relation between a child's verbal level and pairing efficacy: children with the lower scores on the Behavioral Language Assessment Form (Sundberg and Partington, 1998) exhibited more conditioning. These findings confirm in a single study what has been so far only suspected informally.

A low-cost platform for eye-tracking research: Using Pupil© in behavior analysis.

Tracking eye movements is being increasingly recognized as a valuable source of information about stimulus control. So far, however, eye-tracking research has suffered from accessibility issues, with expensive hardware and closed-source software. In this article we review Pupil©, an eye-tracking platform developed by Pupil Labs and that combines open-source software with low-cost hardware components. We offer concrete recommendations about Pupil use in stimulus-control research and we show how the software can be extended to automatize the analysis of gaze data. Finally, we present the results of a study of visual discrimination and conditioned reinforcement conducted with Pupil, establishing the usefulness of this platform as a research tool in behavior analysis.

Reforçamento operante e seleção natural: a analogia inútil / Operant reinforcement and natural selection: the useless analogy

Atualmente é bastante comum, nas discussões teóricas sobre Análise do Comportamento, mencionar a"seleção pelas consequências" como um modo causal específico e como um esquema integrador da disciplina com a biologia evolutiva. Contudo, falar de "seleção" no contexto do reforçamento operante constitui claramente um discurso analógico ou metafórico. Esta nota teórica tem três objetivos principais:primeiro, clarificar as condições nas quais uma analogia desta natureza pode ser aceita ou não; segundo,resumir e simplificar os argumentos de Tonneau e Sokolowski (2000, 2001 ) contrários à analogia entre reforçamento operante e seleção natural; e finalmente, examinar se desenvolvimentos recentes na disciplina refutaram as conclusões negativas destes autores

Correlations among stimuli affect stimulus matching and stimulus liking.

Human subjects were exposed to AB, AC stimulus pairs and then to matching-to-sample tests of stimulus equivalence (B-A, C-A, B-C, C-B) or to a task in which stimulus compounds (BA, CA, BC, CB) were rated for attractiveness. Matching-to-sample tests revealed emergent B-A, C-A, B-C, and C-B choices, replicating previous results in the literature. The mean proportion of correct, emergent choices increased as a function of exposure to the AB, AC pairs. On the rating task, the liking scores of all stimulus compounds also increased as a function of exposure to the AB, AC pairs. After limited exposure to these pairs, however, the liking scores of the BC and CB compounds were negative. These findings are discussed in relation to perceptual and associative perspectives on the behavioral effects of stimulus correlations.

Discrete and continuous stimulus control in the A-not-B sandbox task.

In behavior-analytic studies of generalization, stimulus control appears to be discrete rather than continuous: after two behavior patterns R1 and R2 are trained in the presence of stimuli A and B, respectively, tests of intermediate stimuli evoke R1 and R2 in varying proportions rather than an actual mix of R1 and R2. By contrast, theories and data from developmental psychology suggest that spatial searches in the A-not-B sandbox task may be continuous: after burying an object at position A and then at position B, children may search the sand surface at positions that are actually intermediate between A and B. The published evidence so far has been ambiguous, however, because researchers typically report group means rather than response distributions, and group means intermediate between A and B might be statistical artefacts of averaging across subjects. Here we report two A-not-B sandbox studies designed to address this issue. In Experiment 1, which employed a purely motor A-not-B procedure, stimulus control was found to be continuous. In Experiment 2, which used a purely observational A-not-B procedure, stimulus control was basically discrete but also exhibited continuous aspects. These findings are discussed in relation to cognitive and behavior-analytic approaches to stimulus control.

Learning in the temporal bisection task: Relative or absolute?

We examined whether temporal learning in a bisection task is absolute or relational. Eight pigeons learned to choose a red key after a t-seconds sample and a green key after a 3t-seconds sample. To determine whether they had learned a relative mapping (short→Red, long→Green) or an absolute mapping (t-seconds→Red, 3t-seconds→Green), the pigeons then learned a series of new discriminations in which either the relative or the absolute mapping was maintained. Results showed that the generalization gradient obtained at the end of a discrimination predicted the pattern of choices made during the first session of a new discrimination. Moreover, most acquisition curves and generalization gradients were consistent with the predictions of the learning-to-time model, a Spencean model that instantiates absolute learning with temporal generalization. In the bisection task, the basis of temporal discrimination seems to be absolute, not relational.

A portable system for studying discrete-trial group choice.

Whether groups of people or animals behave optimally in relation to resources is an issue of interest to psychology, ecology, and economics. In behavioral ecology, the simplest model of optimal group choice is the ideal free distribution (IFD). The IFD model has been tested in humans with discrete or continuous inputs and through manual or automated procedures (e.g., Kraft, Baum, & Burge, 2002; Madden, Peden, & Yamagushi, 2002). Manual procedures tend to be time consuming, however, whereas automated procedures typically require access to a computer network. In this article, we describe a new automated system for discrete-trial tests of the IFD model. Our protocol involves a single computer connected to a digital projector (for stimulus presentation) and a network of gamepads (for registering choices). The system is comparatively inexpensive, easy to install, easy to transport, and it permits the automated collection of group data in minimal time. We show that the data generated through this protocol are comparable to those previously reported in the IFD literature.

What do humans learn in a double, temporal bisection task: absolute or relative stimulus durations?

The relative-coding hypothesis of temporal discrimination asserts that humans learn to respond to the relative duration of stimuli ("short" and "long"). The most frequently used procedure to test the hypothesis is the double bisection task. In one task, participants learn that red and green are the correct comparisons following 2s (short) and 5s (long) samples respectively. In another task, participants learn that triangle and circle are the correct comparisons following 3.5s (short) and 6.5s (long) samples, respectively. Later the samples of one task are tested with the comparisons of the other task, and vice versa. According to the hypothesis, participants will choose red following a 3.5s sample because that sample is short and red is the comparison that goes with short. Similarly, they will choose circle following 5s samples because that sample is long and circle goes with long. We replicated this procedure and improved it by introducing several sample durations during testing to obtain the whole psychometric function of each task. Results from Experiment 1 only partially corroborated the relative-coding hypothesis. Results from Experiment 2 did not corroborate the hypothesis. The combined data from Experiments 1 and 2 partially corroborate the hypothesis. Alternatively, we present an explanation of relative-coding-like results that posits exclusively absolute coding of temporal stimuli.

Hamsters' (Mesocricetus auratus) memory in a radial maze analog: the role of spatial versus olfactory cues.

The golden hamster's (Mesocricetus auratus) performance on radial maze tasks has not been studied a lot. Here we report the results of a spatial memory task that involved eight food stations equidistant from the center of a circular platform. Each of six male hamsters depleted the food stations along successive choices. After each choice and a 5-s retention delay, the hamster was brought back to the center of the platform for the next choice opportunity. When only one baited station was left, the platform was rotated to evaluate whether olfactory traces guided hamsters' choices. Results showed that despite the retention delay hamsters performed above chance in searching for food. The choice distributions observed during the rotation probes were consistent with spatial memory and could be explained without assuming guidance by olfactory cues. The radial maze analog we devised could be useful in furthering the study of spatial memory in hamsters.

Belief Modification in Cognitive Therapy

One of the central assumptions of cognitive therapy is that psychological disorders are caused, at least in part, by dysfunctional beliefs. One of the goals of therapy is therefore to modify these beliefs or to replace them by more adaptive ones. Among other treatments, this cognitive strategy has proved clinically successful in a number of cases. The efficacy of belief modification in cognitive therapy raises a number of theoretical and conceptual issues for behavior analysis. I discuss some of the attending difficulties and suggest a possible way out (AU)

Uno de los supuestos en que se basa la terapia cognitiva es que los trastornos psicológicos son provocados, por lo menos en parte, por creencias disfuncionales. Por lo tanto, uno de los objetivos de la terapia es modificar estas creencias o substituirlas por otras, más adaptativas. Entre otros tratamientos, esta estrategia cognitiva se ha mostrado efectiva en numerosos casos. La eficacia de la modificación de las creencias plantea varias cuestiones teóricas y conceptuales para el análisis de las conductas. En este artículo se abordan algunas de las dificultades que presenta y se avanzan algunas posibles soluciones (AU)

Measuring resistance to change at the within-session level.

Resistance to change is often studied by measuring response rate in various components of a multiple schedule. Response rate in each component is normalized (that is, divided by its baseline level) and then log-transformed. Differential resistance to change is demonstrated if the normalized, log-transformed response rate in one component decreases more slowly than in another component. A problem with normalization, however, is that it can produce artifactual results if the relation between baseline level and disruption is not multiplicative. One way to address this issue is to fit specific models of disruption to untransformed response rates and evaluate whether or not a multiplicative model accounts for the data. Here we present such a test of resistance to change, using within-session response patterns in rats as a data base for fitting models of disruption. By analyzing response rate at a within-session level, we were able to confirm a central prediction of the resistance-to-change framework while discarding normalization artifacts as a plausible explanation of our results.

Function transformation without reinforcement.

In studies of function transformation, participants initially are taught to match stimuli in the presence of a contextual cue, X; the stimuli to be matched bear some formal relation to each other, for example, a relation of opposition or difference. In a second phase, the participants are taught to match arbitrary stimuli (say, A and B) in the presence of X. In a final test, A often displays behavioral functions that differ from those of B, and can be predicted from the nature of the relation associated with X in the initial training phase. Here we report function-transformation effects in the absence of selection responses and of their reinforcers. In three experiments with college students, exposure to relations of difference or identity modified the responses given to later stimuli. In Experiment 1, responses to a test stimulus A varied depending on preexposure to pairs of colors that were distinct from A but exemplified relations of difference or identity. In Experiment 2, a stimulus A acquired distinct functions, depending on its previous pairing with a contextual cue X that had itself been paired with identity or difference among colors. Experiment 3 confirmed the results of Experiment 2 with a modified design. Our data are consistent with the notion that relations of identity or difference can serve as stimuli for Pavlovian processes, and, in compound with other cues, produce apparent function-transformation effects.

Windows.

Some models of performance assume that behavior depends on environmental quantities (for example, rates of reinforcement) that are defined over intervals of fixed duration. Although such window models may serve as useful approximations, they are incompatible with well-known properties of behavior (for instance, sensitivity to delay). Window models with variable window length, however, are more difficult to refute. This article examines some implications of the assumption of random window length. Variable windows are shown to produce continuous forgetting and temporal discounting functions, to display properties analogous to parallel aggregation, and to make reasonable predictions about steady-state relations between reinforcement and responding. Issues of interpretation nonetheless suggest that alternatives to window models should be developed.

Function transfer in human operant experiments: the role of stimulus pairings.

Although function transfer often has been studied in complex operant procedures (such as matching to sample), whether operant reinforcement actually produces function transfer in such settings has not been established. The present experiments, with high school students as subjects, suggest that stimulus pairings can promote function transfer in conditions that closely approximate those of matching to sample. In Experiment 1, the subjects showed transfer of operant responding from three geometric figures (C1, C2, C3) to three colored shapes (B1, B2, B3) when the latter were paired with the former. Experiment 2 involved two groups of subjects. In the matching group, subjects matched the colored shapes with the geometric figures; in the yoked group, the shapes were merely paired with the geometric figures, and the schedule of stimulus pairing was yoked to the performance of the subjects in the matching group. Both groups of subjects showed function transfer. Experiment 3 documented function transfer from C stimuli to B stimuli through indirect stimulus pairings (A-B, A-C). In Experiment 4, function transfer was obtained even though the subjects vocalized continuously during the pairing trials, presumably preventing covert verbalization that might mediate transfer effects. Our results are consistent with a Pavlovian account and raise difficulties for current operant theories of function transfer.