Delayed response, preoperative overtraining, and prefrontal lesions in the rat

An earlier study in this laboratory found that preoperative overtraining improved retention of a delayed alternation task after prefrontal lesions in the rat. In this study, however, it was found that preoperative overtraining did not improve performance of the rat in a delayed response task following prefrontal lesions. These results support the hypothesis that preoperative overtraining can improve postoperative performance only when postoperative recovery is ordinarily present, as it is with delayed alternation. but not with delayed response, in the prefrontal rat. This suggests that effects of preoperative overtraining and postoperative recovery may be mediated by similar mechanisms. It further suggests that a shift of function, which seems to account for postoperative recovery, may occur in some parts of the normal adult brain as a result of overtraining.     

Delayed alternation in the pigeon

Pigeons were studied in a delayed-response task requiring alternation of key pecks on two response keys. Blackouts of from 1 to 10 sec intervened between successive choices on the two keys.

The following results were obtained: (1) Birds performed at well above chance accuracy on all the delays tested. Accuracy was generally lowest at 1- and 10-sec delays. (2) Overt postural orientations during the delay interval appeared to mediate accurate key-pecking behavior. (3) The shape of the delay vs. accuracy function was discussed in terms of the possibly confounding influences of (a) stimulus “trace” variables, and (b) aversive effects of the time outs produced by incorrect responding.

     

Delayed choice responding by pigeons when the correct response is not predictable from the sample stimulus.

Food-deprived pigeons were presented with a row of four response keys situated above a grain hopper aperture. At the start of a trial, three of four keys were randomly selected and illuminated white for six seconds. After a variable blackout period, one of the three previously white keys and the previously dark key were illuminated green, and the remaining white keys were reilluminated as before. A response to the green key that was previously white was reinforced with three-second access to gain, a response to any other key resulted in a three-second blackout and the start of a new trial. Five of six subjects responded to the correct green key more often than chance at an interstimulus interval of 1.5 seconds, and they displayed maximal performance at different intertrial interval values ranging from 15 to 60 seconds. Choice accuracy decreased for all but one subject as the interstimulus interval was increased. For the range of interstimulus interval durations employed, decrements in choice accuracy were qualitatively similar to, but lower than those typically obtained from, delayed-matching-to-sample or delayed-pair comparison procedures.     

Delayed matching-to-sample performance of hens: Effects of sample duration and response requirements during the sample

Six domestic hens were trained under a delayed matching-to-sample procedure with red and green keylights as sample and comparison stimuli and a 1.5-s delay interval. The hens were trained to stop pecking the sample stimuli when a tone sounded. Duration of the sample stimuli (2 to 10 s) and the number of pecks required on the key on which these stimuli were presented (0 to 10) were altered across conditions. Both the response requirement on the sample key and the duration of sample presentations affected accuracy. These findings are in agreement with those of earlier studies using other species and somewhat different procedures.     

Delayed attentional engagement in the attentional blink

Observers often miss the 2nd of 2 visual targets (first target [T1] and second target [T2]) when these targets are presented closely in time; the attentional blink (AB). The authors hypothesized that the AB occurs because the attentional response to T2 is delayed by T1 processing, causing T2 to lose a competition for attention to the item that follows it. The authors investigated this hypothesis by determining whether the AB is attenuated when T2 is precued. The results from 4 experiments showed that the duration and magnitude of the AB were substantially reduced when T2 was precued. The observed improvement in T2 report did not occur at the expense of T1 report, suggesting that processing of T1 was already completed or was at least protected when the cue was presented. The authors conclude that, during the AB, there is a delay between detection and the selection of target candidates for consolidation in short-term memory.     

Delayed N2 response in Go condition in a visual Go/Nogo ERP study in children who stutter

Purpose of the studyThe main aim of the study was to investigate the attentional and inhibitory abilities and their underlying processes of children who stutter by using behavioural measurement and event-related potentials (ERP) in a visual Go/Nogo paradigm.MethodsParticipants were 11 children who stutter (CWS; mean age 8.1, age range 6.3–9.5 years) and 19 typically developed children (TDC; mean age 8.1, age range 5.8–9.6 years). They performed a visual Go/Nogo task with simultaneous EEG recording to obtain ERP responses.ResultsResults showed that CWS had longer N2 and P3 latencies in the Go condition compared to the TDC. In contrast, the groups did not differ significantly in the Nogo condition or behavioural measures.ConclusionsOur findings did not confirm less efficient inhibitory control in CWS but suggest atypical attentional processing such as stimulus evaluation and response selection.Educational Objectives: The reader will be able to (a) describe recent findings on attention and inhibitory control in children who stutter, (b) describe the measurement of attentional processing, including inhibitory control, and (c) describe the findings on attentional processing in children who stutter as indexed by the event-related potentials in a visual Go/Nogo paradigm.     

Evaluation of the Delayed Discovery Case

Summary

In this chapter, practicing lawyer Michael S. Morey guides the reader through the complex legal and non-legal issues involved in evaluating whether legal action should be pursued on behalf of an adult survivor of childhood sexual abuse. After analyzing how evaluation of sexual abuse cases differs from that in most other personal injury cases, he presents a model for non-suggestive yet thorough client interviewing and case evaluation to help both survivor and lawyer decide whether to pursue litigation. Viability of a case, determined by three critical legal issues, does not necessarily mean litigation ought to be pursued, and he explores how to make the initial interview a valuable resource to survivors, whether or not legal action is ultimately sought, with practical tips and a reproducible intake form.     

Delayed rule following

Although the elements of a fully stated rule (discriminative stimulus [S(D)], some behavior, and a consequence) can occur nearly contemporaneously with the statement of the rule, there is often a delay between the rule statement and the S(D). The effects of this delay on rule following have not been studied in behavior analysis, but they have been investigated in rule-like settings in the areas of prospective memory (remembering to do something in the future) and goal pursuit. Discriminative events for some behavior can be event based (a specific setting stimulus) or time based. The latter are more demanding with respect to intention following and show age-related deficits. Studies suggest that the specificity with which the components of a rule (termed intention) are stated has a substantial effect on intention following, with more detailed specifications increasing following. Reminders of an intention, too, are most effective when they refer specifically to both the behavior and its occasion. Covert review and written notes are two effective strategies for remembering everyday intentions, but people who use notes appear not to be able to switch quickly to covert review. By focusing on aspects of the setting and rule structure, research on prospective memory and goal pursuit expands the agenda for a more complete explanation of rule effects.     

Delayed reinforcement in a multiple schedule

Three rats and a pigeon were first trained on a two-component multiple schedule in which reinforcement in the two components occurred immediately after a response. Later, reinforcement in one component was delayed by a few seconds. During both stages of the experiment, reinforcement was scheduled by equal variable- (pigeon) or random-interval (rats) schedules in the two components. The main effect of the delayed reinforcement was to increase the rate of responding in the unchanged (non-delay) component. This behavioral contrast effect did not appear in all cases to be dependent upon a reduction in the rate of responding or the frequency of reinforcement in the delay component. This finding suggests that a reduction in response rate and/or reinforcement frequency in one component of a multiple schedule may not be a necessary prerequisite for the occurrence of behavioral contrast. This finding is, however, consistent with an explanation that suggests that behavioral contrast results from the introduction of a less-preferred condition in one component of a multiple schedule, since it is known that animals “prefer” immediate to delayed reinforcement.     

Delayed one-trial extinction of the McCollough effect

Initial tests of the McCollough effect were made on separate groups at delays of 4, 24 or 96 h after induction, with little apparent decrement. Subsequent tests were made at 4, 24 and 96 h after each initial test delay, again using separate subject groups in order to avoid test-induced extinction. All tests consisted of magentagreen nulling of the aftereffect. A single test session, whenever administered, seems to initiate a decay or extinction process lasting several days, resembling the time course shown by repeated testing. These results are difficult to reconcile with a perceptual conditioning model of the McCollough effect.     

Delayed sidetone in relation to the reading of different materials

Several studies were conducted with speakers reading short phrases aloud while experiencing one amount or another of delayed sidetone (0.0–0.30 sec). The phrases represented different numbers of syllables, different types of syllables, different numbers of phonemes, and first and second languages. Additional syllables and unfamiliar material consistently increased the reading time of the speakers disproportionately. The reading of syllables of two and four sounds was apparently more retarded by delayed sidetone than ones of three sounds. Two-sound syllables comprised of vowel-consonants required more time to read than ones comprised of consonant-vowels. The effect of additional phonemes, with the type of syllables held constant, added linearly in the reading time of the phrases. The syllabic characteristics, the length, and probably the familiarity of the material affected the reading time nonlinearly.     

Delayed matching in the capuchin monkey with brief sample durations

Two capuchin monkeys were trained in a delayed matching-to-sample task in which the duration that the sample was available for viewing was very brief, 0.075 to 0.45 sec. The matching performance of one animal was above chance with delay (retention) intervals as long as 4 min; the other S showed significant matching with a 2-min retention interval. The performance of both Ss was independent of sample exposure duration, indicating that their capacity to match successfully at long retention intervals is not dependent on repeated viewing of the sample stimulus. The marked practice effect shown by one S with prolonged training at 2-min delay suggests the capacity of “learning how to remember.” A constant high performance level on 2-sec delay control trials indicates that the observed practice effect was not the result of enhanced attending to the sample stimulus.