FUNCTIONAL ANALYSIS AND TREATMENT OF EYE POKING

In four studies we analyzed the eye poking of a youth with profound disabilities. In Study 1, a functional analysis showed that eye poking occurred during the no-attention condition, but not during demand, attention, or recreation conditions. The analysis did not identify socially mediated variables involved in the maintenance of eye poking; rather, eye poking may have been maintained by consequences produced directly by the response. In Study 2 we had the student wear goggles to prevent potential reinforcement from finger—eye contact. The results of Study 2 indicated that eye-poking attempts were reduced when the student wore goggles. We then tested in Study 3 the effects of two alternative topographies of stimulation. Study 3 demonstrated that eye poking was reduced when a video game was provided as a competing source of visual stimulation, and that music was less effective in reducing eye poking. In Study 4, a contingency analysis using the video game was conducted in an attempt to (a) reduce the frequency of eye poking and (b) study whether the video game functioned as a reinforcer. The results of Study 4 demonstrated substantive reductions in the frequency of eye poking, and suggested that the video game served as a reinforcer.     

Using a stimulus correlated with reprimands to suppress automatically maintained eye poking

A functional analysis indicated that chronic eye poking exhibited by a woman with profound mental retardation persisted in the absence of social contingencies. We initiated a procedure in which a therapist delivered a punisher (mild reprimand) contingent on eye poking in the presence, but not the absence, of a neutral stimulus (wristbands). Subsequently, eye poking was suppressed when the participant wore the wristbands in novel environments without the reprimand contingency.     

Brief functional analysis and treatment of eye poking

A brief functional analysis suggested that eye poking exhibited by a 5‐year‐old boy diagnosed with cortical visual impairment was maintained by automatic reinforcement. Levels of eye poking in additional conditions suggested that the behavior might be maintained by visual stimulation. Response blocking through the use of safety goggles effectively reduced eye poking in the analog setting. Data from the natural environment suggest that, during intervention, eye poking was confined to times when response blocking was not in effect. Copyright © 2002 John Wiley & Sons, Ltd.     

Effects of an Antecedent Intervention on Repetitive Behaviors of a Child With Autism

Repetitive self-injurious eye poking and stereotypic hand clapping were assessed in a child with autism and hearing impairment. A functional behavioral assessment conducted to identify the variables maintaining eye-poking behaviors indicated automatic reinforcement. Choice and environmental enrichment strategies were implemented to decrease the motivating operations associated with eye poking. Providing a choice of toys to hold in his hand led to the greatest reductions in both repetitive eye poking and hand clapping. Three follow-up observations were conducted 9 months after the intervention, which indicated that eye poking was eliminated and hand clapping was greatly reduced. This antecedent intervention was simple and effective, two hallmarks of sustainable behavior interventions.     

DISTINGUISHING BETWEEN EXTINCTION AND PUNISHMENT EFFECTS OF RESPONSE BLOCKING: A REPLICATION

Lerman and Iwata (1996) described a method for distinguishing between sensory extinction and punishment effects of response blocking on self-injurious behavior maintained independent of social contingencies. Results of their study suggested that blocking decreased the self-injurious hand mouthing of their participant via punishment. The current replication of these procedures with the self-injurious eye poking of a woman with developmental disabilities produced patterns of responding indicating that, for this participant, blocking functioned as an extinction procedure.     

Bouts of responding: the relation between bout rate and the rate of variable-interval reinforcement

By nose poking a lighted key, rats obtained food pellets on either a variable-interval schedule of reinforcement or a schedule that required an average of four additional responses after the end of tile variable-interval component (a tandem variable-interval variable-ratio 4 schedule). With both schedule types, the mean variable interval was varied between blocks of sessions from 16 min to 0.25 min. Total rate of key poking increased similarly as a function of the reinforcer rate for the two schedule types, but response rate was higher with than without the four-response requirement. Analysis of log survivor plots of interresponse times showed that key poking occurred in bouts. The rate of initiating bouts increased as a function of reinforcer rate but was either unaffected or was decreased by adding the four-response requirement. Within-bout response rate was insensitive to reinforcer rate and only inconsistently affected by the four-response requirement. For both kinds of schedule, the ratio of bout time to between-bout pause time was approximately a power function of reinforcer rate, with exponents above and below 1.0.     

Prevalence and situational causes of stereotyped behaviors in blind infants and preschoolers

Parents of 85 blind children aged from 10 months to the 6th year of life were asked regarding the frequency, duration and typical situations of the occurrence of various stereotypic behavors in their children. The Bielefeld Parents' Questionnaire for Blind and Sighted Infants and Preschoolers was used as the instrument of measurement. All of the children displayed at least one stereotypic behavior; most displayed several stereotypic behaviors according to the parents' reports. Eye poking and body rocking dominated within the prevalence hierarchy. Four typical situations could be identified in which stereotypic behaviors were shown: monotony, arousal, demand, and during feeding or eating. The results suggested that repetitive hand and finger movements, stereotypic manipulation of objects, and making a face(s) mainly occur within arousal situations whereas eye poking, whimpering, and sucking thumbs or fingers especially are linked to monotony.This research was carried out within a research program on early intervention and family care for blind infants and preschoolers. This program is part of the Special Research Unit on Prevention and Intervention in Childhood and Adolescence (Sonderforschungsbereich No. 227) at the University of Bielefeld funded by the German Research Association (DFG). The authors would like to thank Gail Weingart and Jonathan Harrow (University of Bielefeld) for translating this paper from German.     

Bouts of responding on variable-interval schedules: effects of deprivation level

Rats obtained food pellets on a variable-interval schedule of reinforcement by nose poking a lighted key. After training to establish baseline performance (with the mean variable interval set at either 60, 120, or 240 s), the rats were given free access to food during the hour just before their daily session. This satiation operation reduced the rate of key poking. Analysis of the interresponse time distributions (log survivor plots) indicated that key poking occurred in bouts. Prefeeding lengthened the pauses between bouts, shortened the length of bouts (less reliably), and had a relatively small decremental effect on the response rate within bouts. That deprivation level affects mainly between-bout pauses has been reported previously with fixed-ratio schedules. Thus, when the focus is on bouts, the performances maintained by variable-interval schedules and fixed-ratio schedules are similarly affected by deprivation.     

Stimuli previously associated with reinforcement mitigate resurgence

Resurgence refers to the recurrence of an extinguished target behavior following subsequent suspension of alternative reinforcement. Delivery of reinforcers during extinction of alternative behavior has been shown to mitigate resurgence. The present experiment aimed to determine whether delivering stimuli associated with reinforcers during resurgence testing similarly mitigates resurgence. Three groups of rats pressed target levers for food according to variable‐interval 15‐s schedules during Phase 1. In Phase 2, lever pressing was extinguished, and an alternative nose‐poke response produced alternative reinforcement according to a variable‐interval 15‐s schedule. Food reinforcement was always associated with illumination of the food aperture and an audible click from the pellet dispenser during Phases 1 and 2. Phase 3 treatments differed between groups. For one group, nose poking continued to produce food and food‐correlated stimuli. Both of these consequences were suspended for a second group. Finally, nose poking produced food‐correlated stimuli but not food for a third group. Target‐lever pressing resurged in the group that received no consequences and in the group that received only food‐correlated stimuli for nose poking. Resurgence, however, was smaller for the group that received food‐correlated stimuli than for the group that received no consequences for nose poking. Target‐lever pressing did not increase between phases in the group that continued to receive food and associated stimuli. Thus, delivery of stimuli associated with food reinforcement after suspension of food reduced but did not eliminate resurgence of extinguished lever pressing. These findings contribute to potential methodologies for preventing relapse of extinguished problem behavior in clinical settings.     

Autoshaped head poking in the mouse: a quantitative analysis of the learning curve

In autoshaping experiments, we quantified the acquisition of anticipatory head poking in individual mice, using an algorithm that finds changes in the slope of a cumulative record. In most mice, upward changes in the amount of anticipatory poking per trial were abrupt, and tended to occur at session boundaries, suggesting that the session is as significant a unit of experience as the trial. There were large individual differences in the latency to the onset of vigorous responding. "Asymptotic" performance was unstable; large, bidirectional, and relatively enduring changes were common. Given the characteristics of the individual learning curves, it is unlikely that physiologically meaningful estimates of rate of learning can be extracted from group-average learning curves.     

Eye contact as an antecedent to compliant behavior

Many experimenters and practitioners regard eye contact between instructor and learner as a facilitator, if not a prerequisite, to the effective instruction of sighted people. Without scientifically supporting the practice of demanding eye contact, experimenters, nonetheless, advocate its use and offer a variety of procedures to promote its acquisition. To justify the widespread use of demanded eye contact and to explain its role functionally, one experiment and data from six replications with nine subjects are presented. The primary experiment provides an empirical base for the training of eye contact prior to instruction. In a multiple-baseline design across two students demanded eye contact resulted in levels of compliance that were double and triple those of baseline. A tentative functional analysis of demanded eye contact is presented, followed by a discussion of the relationship of eye contact to attending.     

Metamers for Hammer-With-Ability Are Not Metamers for Poke-With-Ability

Studies on dynamic (i.e., kinesthetic) touch perception have shown that perception of many properties of wielded objects are linked to variables related to the rotational inertia of those objects. The broad nature of the sensitivity to such variables invites the question of whether various perceived functional properties of wielded objects are distinct (i.e., whether they map to rotational inertia via different functions) or whether they are perceptually equivalent (i.e., whether they map to opposite extremes of the same function). Two experiments investigated whether hammer-with-ability and poke-with-ability are perceptually equivalent (i.e., metamers) using a metameric matching strategy. The results show that metamers for hammering were not metamers for poking, and vice versa. The results suggest that haptic perception of poke-with-ability and hammer-with-ability are distinct percepts.     

Activation of human motion processing areas during event perception

Observers are able to segment continuous everyday activity into meaningful parts. This ability may be related to processing low-level visual cues, such as changes in motion. To address this issue, the present study combined measurement of evoked responses to event boundaries with functional identification of the extrastriate motion complex (MT+) and the frontal eye field (FEF), two regions related to motion perception and eye movements. The results provided strong evidence that MT+ is activated by event boundaries: Individuals' MT+ regions showed strong responses to event boundaries, and MT+ was collocated with a lateral posterior region that responded at event boundaries. The evidence regarding the FEF was less conclusive: The FEF showed reliable but relatively reduced responses to event boundaries, but the FEF was medial and superior to a frontal area that responded at event boundaries. These results suggest that motion cues, and possibly eye movements, may play key roles in event structure perception.     

Central and peripheral cholinergic involvement in the habituation of investigatory head poking in rats

The effects of some centrally and peripherally acting cholinergic agonists and antagonists on locomotor exploration and investigatory head poking were studied in rats. An apparent disruption of within-trials habituation of locomotion and head-poke frequency was demonstrated for arecoline, nicotine, carbachol, scopolamine, and methylscopolamine. It is suggested that the effect may be a consequence of a drug-induced depression of initial activity. When this factor was eliminated, both scopolamine and methylscopolamine showed some slight attenuation of habituation. The increase in head-poke duration over time in controls was blocked by scopolamine; although peripheral factors were involved, the scopolamine effect had a singinficant central component. The results are discussed in relation to hypothetical links between the cholinergic system and habituation.     

Behavioral contrast in rats with different reinforcers and different response topographies

Experiment I demonstrated positive behavioral contrast in rats when one of two qualitatively different reinforcers (milk and pellets) was removed from a component of a multiple schedule. The contrast effect was larger and more enduring when milk was removed. Experiment II showed that the rats spent more time on the side of a shuttle-box on which milk was freely available than on the side on which pellets were freely available. Experiment III, a partial replication of Experiment I, failed to demonstrate the contrast effect of Experiment I. Experiment IV demonstrated contrast when two topographically distinct responses, nose-key poking and lever pressing, were required in different components of a multiple schedule. These results extend the conditions that generate behavioral contrast in rats.     

Removal of an obstacle: Problem-solving behavior in pigeons

The importance of a subject's personal history in the solution of an obstruction problem was demonstrated with pigeons. Four birds were trained to peck a key located outside the chamber by poking their heads through an opening in a screen. During tests, a white block was placed in front of the opening, so that it was not possible to peck the key without removing the block. All birds failed to remove the block. However, all birds that were subsequently trained to push the white block around the chamber in the absence of the key and a few of the birds trained similarly but with a black block solved the problem by pushing the block aside and pecking the key. One bird showed the abrupt descent in the learning curve that has been considered a characteristic of “insightful” problem solving. All birds maintained their successful performance after a 1-month interval with no intervening tests.     

Eye movements reflect and shape strategies in fraction comparison

The comparison of fractions is a difficult task that can often be facilitated by separately comparing components (numerators and denominators) of the fractions—that is, by applying so-called component-based strategies. The usefulness of such strategies depends on the type of fraction pair to be compared. We investigated the temporal organization and the flexibility of strategy deployment in fraction comparison by evaluating sequences of eye movements in 20 young adults. We found that component-based strategies could account for the response times and the overall number of fixations observed for the different fraction pairs. The analysis of eye movement sequences showed that the initial eye movements in a trial were characterized by stereotypical scanning patterns indicative of an exploratory phase that served to establish the kind of fraction pair presented. Eye movements that followed this phase adapted to the particular type of fraction pair and indicated the deployment of specific comparison strategies. These results demonstrate that participants employ eye movements systematically to support strategy use in fraction comparison. Participants showed a remarkable flexibility to adapt to the most efficient strategy on a trial-by-trial basis. Our results confirm the value of eye movement measurements in the exploration of strategic adaptation in complex tasks.     

Some factors involved in the comparison of response systems: acquisition, extinction, and transfer of head-poke and lever-press Sidman avoidance

Head poking, a suggested natural escape reaction to shock for the rat, was compared to lever pressing in a Sidman avoidance study. Both responses could be emitted at any time, but only one was effective in a given session. Acquisition and extinction of the two responses were compared under both signalled and unsignalled avoidance. Then, a test for transfer was conducted in which acquisition conditions were re-instated, but the effectiveness of the responses was reversed. Three differences between responses were noted: (a) head poking was superior in reducing shock rates under signalled conditions; (b) head poking was more resistant to extinction, especially under signalled conditions; (c) under unsignalled conditions, animals were unable to learn to head poke if they had previously learned to lever press. Findings a and c were pursued in later experiments. Finding a depended on the location of the warning signal with respect to the response system. When the lever press required approach to the warning signal, the head poke was superior. But when the head poke required approach to the warning signal, the two responses were equally effective. Finding c depended on the absence of feedback for head poke during transfer. Two conclusions are offered: first, the two responses appear to obey the same laws when their topographical differences are taken into account. Second, response feedback appears to be more critical in transfer than in original acquisition.     

Eye centring in portraits: a theoretical and empirical evaluation

Tyler (1998 Nature 392 877) proposed that 'painters centre one eye in portraits', and that this is a hidden aesthetic principle used implicitly by artists and by viewers of portraits. We assess that hypothesis in three related studies: a Monte-Carlo analysis of eye placement in synthetic faces randomly placed within a frame; a survey of eye position in 786 painted portraits from Western art of the past six centuries; and an experimental study in which fifty subjects were asked which of two versions of 60 pairs of portraits they preferred, in only one of which the eye was precisely centred. Taken together, the three studies showed no evidence to support Tyler's hypothesis, and in particular there was no evidence for subjects having an aesthetic preference for a centred eye in portraits. We conclude that one eye tends to be relatively close to the vertical midline because of geometric constraints on the placing of a relatively large object, the head, within a pictorial frame.