Effects of amount and kind of prior target-uncertainty reduction in the repeated presentations paradigm

Single letters were presented for varying numbers of repeated brief exposures. The S reported on the target after each presentation, identifying only those symbols perceived with certainty. A d’ analysis of the results revealed that target-uncertainty reduction produced significant facilitation in the average level of perceptual sensitivity only in a condition in which the target symbol was exposed prior to each trial. Prior knowledge of the target symbol without prior exposure produced a measurable, but nonsignificant, facilitation in sensitivity. The data suggested that the growth curve normally associated with the repeated-presentations paradigm may be the result of a progressive liberalization of the S’s criterion for reporting in some studies. The data further showed that prior exposure and perhaps prior knowledge can significantly alter the shape of the repetition curve when the target is a single letter. These findings were interpreted as an indication that both amount and kind of target-uncertainty reduction can produce significant changes in the repetition effect for single letters.     

Overhabituation and dishabituation: Effects of extraversion and amount of training

The Eysenck (1967) hypothesis that introverts have higher levels of cortical activation than extraverts has received support in a number of psychophysiological studies, though there is not complete consistency. The present study extended the habituation paradigm used in some previous work to include an examination of differences between extraverts and introverts during and following long-term overhabituation. Electrodermal activity was recorded while 72 extraverts and 72 introverts were subjected to criterion auditory habituation to a 1000-Hz, 90-db tone, followed by 60, 100, or 140 trials of overhabituation. The overhabituation run was followed by a test stimulus of 7000 Hz and a final repetition of the standard stimulus. Results showed that introverts increased in response frequency with increasing overhabituation exposure, while extraverts showed an increase only from 100 to 140 trials. In addition, the hypothesis that differences in test response amplitude favoring introverts would be eliminated by extended overhabituation training was supported. Specifically, extraverts showed increased responses at 100 and 140 trials, while introverts remained approximately constant across the three conditions. Finally, results supported the Sokolov hypothesis that overhabituation training produces test responses of larger amplitude.     

Child performance on discrimination tasks: Effects of amount of stimulus variation

Two independently conducted studies investigated stimulus variation effects on children's discrimination learning. The stimuli in the first study were generated by a conjunctive rule and were presented in pairs. Mean trials to criterion was significantly lower for the single-feature change treatment (17.4) than for the multiple-feature change treatment (29.9). Single-feature change-treatment transfer scores were significantly higher only for stimuli that differed in terms of one of the features. The second study not only replicated the initial finding concerning the single-feature change treatment but also found that students made more errors in reaching criterion when stimuli were generated by an exclusive disjunctive rule and were presented singly. For all tasks, the single-feature change treatment with stimuli presented in pairs was accompanied by fewer errors to criterion than the other treatments.     

Effects of Self-Recording and Contingent Credit on Balancing Participation Across Students

This study compared the effects of students’ (a) receiving participation credit with and without self-recording their participation and (b) self-recording participation with and without receiving credit for participation on the percentage of students functioning at four participation levels: non-participation, credit-level participation, frequent participation (slightly above credit-level), and dominant participation (2.5+ times above credit-level). Participants came from three sections of a relatively large discussion course (initially 55 students per section). Credit (with and without self-recording participation) decreased the percentage of both non-participants and dominant participants and increased the percentage of credit-level participants, thus creating greater balance in participation across students in each class. In contrast, self-recording versus non-self-recording (with and without credit) did not significantly differentiate the percentages of either non-participants or frequent participants but did differentiate the percentages of credit-level and dominant participants under the recording conditions.     

Contingent capture for onsets and offsets: attentional set for perceptual transients

Four experiments were conducted to examine whether attentional set affects the ability of visual transients (onsets and offsets) to capture attention. In the experiments, visual search for an identity-defined target was conducted. In the first 3 experiments, the target display either onset entirely or was revealed by offsetting camouflaging line segments to reveal letters. Prior to the target display, there was a noninformative cue, either an onset or an offset, at one of the potential target locations. Cues that shared the same transient feature as the target display captured attention. The lack of predictable target transients led to attentional capture by all forms of transients. The final experiments with luminance changes without offsets or onsets showed attentional capture when the luminance changes were large. The results suggest that attentional set can be broadly or narrowly tuned to detect changes in luminance.     

Effects of amount of information on judgment accuracy and confidence

When a person evaluates his or her confidence in a judgment, what is the effect of receiving more judgment-relevant information? We report three studies that show when judges receive more information, their confidence increases more than their accuracy, producing substantial confidence–accuracy discrepancies. Our results suggest that judges do not adjust for the cognitive limitations that reduce their ability to use additional information effectively. We place these findings in a more general framework of understanding the cues to confidence that judges use and how those cues relate to accuracy and calibration.     

Humans' sensitivity to variation in reinforcer amount: Effects of the method of reinforcer delivery

Two experiments examined human subjects' sensitivity to variation in reinforcer amount under different methods of reinforcer delivery. Subjects chose between schedules varying in terms of amount and/or delay of reinforcement, the reinforcer being points exchangeable for money. In Experiment 1, reinforcer amount was manipulated by varying the monetary value of the points across conditions while the number of seconds of access to a consummatory response remained constant. Choice was strongly sensitive to reinforcer amount and indicative of self-control, as in previous experiments. In Experiment 2, reinforcer amount was manipulated by automatically delivering different numbers of points during the amount period, and the consummatory response was eliminated. Sensitivity to variation in reinforcer amount was significantly lower than in Experiment 1. Furthermore, the subjects in Experiment 2 exhibited significantly less self-control than did the subjects in Experiment 1. Humans' sensitivity to variation in reinforcer amount appears to be affected by factors that enhance the discrimi-nability of the consequences of responding.     

Multiple effects of performance-contingent pay for wait-persons

The owners of three restaurants requested help with the pay of waitpersons who were paid by the hour. The waitpersons asked for raises which the owners said they could not afford. This research changed the method of compensating waitpersons by making their pay contingent on dollars of food sold. Increased productivity and increased earnings per hour of work for all of the waitpersons followed the beginning of the performance-contingent pay. Most of the waitpersons also earned increased take-home pay when the performance-contingent pay began. There was little improvement in labor costs per dollar of food sold, a measure of benefit to the owners. The fact that benefits to workers occurred without benefits to owners is contrary to common views about the effects of performance-contingent pay.     

Pigeons' preferences for stimulus information: effects of amount of information

A concurrent-chain procedure was used to study pigeons' preferences as a function of amount of information. Pigeons chose between two terminal links. Both terminal links ended in food reinforcement with probability (p) and in blackout with probability (1–p). One terminal link (noninformative link) was signalled by a stimulus uncorrelated with either food or blackout. The other terminal link (informative link) was signalled by stimuli correlated with these outcomes. Amount of information conveyed by these stimuli was varied across conditions by changing the probability of reinforcement (p) and blackout (1–p). The pigeons strongly preferred the informative link, and preferences were greater at p values above 0.50 than for their complements. The pigeons engaged in different behaviors during the stimulus periods, suggesting that the value of informative stimuli may be in their function as discriminative stimuli for interim activities and terminal responses.     

Contingent Reinforcement Effects on Movement Responses of Prison Inmates to the Holtzman Inkblot Technique

Prison inmates were administered the Holtzman Inkblot Technique (HIT) under conditions of either verbal or nonverbal reinforcement of movement responses. Overall, there were no differences among the verbal, nonverbal, and control groups. Inmates charged with violent crimes were found to give the fewest movement responses. With crime category controlled, more movement responses were given under nonverbal conditions. There were no sex differences for movement responses but testing time increased significantly when administered by the female examiner.     

Consumption-leisure tradeoffs in pigeons: Effects of changing marginal wage rates by varying amount of reinforcement

Pigeons' rates of responding and food reinforcement under simple random-ratio schedules were compared with those obtained under comparable ratio schedules in which free food deliveries were added, but the duration of each food delivery was halved. These ratio-with-free-food schedules were constructed so that, were the pigeon to maintain the same rate of responding as it had under the simple ratio schedule, total food obtained (earned plus free) would remain unchanged. However, any reduction in responding would reduce total food consumption below that under the simple ratio schedule. These “compensated wage decreases” led to decreases in responding and decreases in food consumption, as predicted by an economic model of labor supply. Moreover, the reductions in responding increased as the ratio value increased (i.e., as wage rates decreased). Pigeons, therefore, substituted leisure for consumption. The relationship between these procedures and negative-income-tax programs is noted.     

Memory for questions and amount of processing

Two experiments were carried out on how questions are remembered. Subjects watched a videotape of a series of simple events and then answered 18 questions about these events. The questions were all of the same general syntactic form (e.g., “Did the pencil fall against the jug on A?”, where A refers to a particular location). They were designed to elicit three sorts of answer: “yes,” “no” because the event took place at another location, and “no” because the event did not take place at all. After the subjects had answered the questions, they were given an unexpected test of their ability to recall them. A difference in the memorability of the questions was predicted on the basis of a procedural theory of comprehension and a hypothesis about memory subjects should cease to process a question when they realize that it concerns an event that did not take place, and such questions should be harder to remember because they are processed to a lesser degree than the other sorts of question. Experiment 1 confirmed the predictions, but its results in part could be accounted for by assuming that subjects recalled the original events and used them as a cue to remembering the questions. Experiment 2 eliminated this explanation by showing that when subjects do not have to answer certain questions, their recall of them is very poor. However, the same differences in the memorability of the three sorts of question were obtained for both answered and unanswered questions.     

Maintenance of children's rehearsal strategies: Effects of amount of training and strategy form

Fifty third- and fourth-grade children, assigned to groups varying in Amount (1 or 2 sessions) and Type (cumulative-cluster or cluster) of strategy training or to a control condition, participated in three free recall sessions, two training sessions with blocked lists of common words and a maintenance session with a 50-states list blocked by geographical regions. During strategy training and maintenance, the cumulative-cluster groups recalled more than the cluster and control groups. Amount of training significantly influenced degree of strategy maintenance, but only in the cumulative-cluster strategy. Strategy form was highly correlated with recall in the cumulative-cluster condition, while total study time (effort) was related to recall only in conditions where strategy instructions were not given. The form of the strategy during training predicted transfer form and recall. 100% of the children who received extended training and demonstrated good strategy form during acquisition sessions successfully transferred the strategy to the geography task.     

The roles of carbon monoxide and nitric oxide in the control of the neuroendocrine stress response: complementary or redundant

There is widespread evidence in favour of nitric oxide (NO) acting as a gaseous neurotransmitter in the central nervous system, diffusing from its cells of origin and affecting surrounding neuronal tissue in evanescent three-dimensional waves. This is also true of the hypothalamus, where amongst other activities NO inhibits stimulation of corticotrophin-releasing hormone (CRH) and vasopressin release by inflammatory stressors, effects thought to be mediated by binding with soluble guanylate cyclase (sGC). Carbon monoxide is being increasingly recognised as another gaseous neuromodulator, but with principal effects on other hemoproteins such as cyclo-oxygenase, and a distinctly different profile of localisation.NO is predominantly a pro-inflammatory agent in the periphery while CO is often anti-inflammatory. In the hypothalamus, the actions of CO are also distinct from those of NO,with marked antagonistic effects on the inflammatory release of vasopressin, both in vitro and in vivo, but with little involvement in the regulation of CRH. Thus, it would appear that these apparently similar gases exert quite distinct and separate effects, although they cause broadly similar overall changes in the secretion of neuroendocrine stress hormones. We conclude that these two gases may play significant but different roles in the control of the neuroendocrine stress response, but one common feature may be attenuation of inflammation-induced release of stress hormones.