The effect of crying on long-term memory in infancy

The influence of crying on infants' long-term memory for a learned response was investigated in 3 experiments. In each, infants were trained to move a crib mobile containing 10 identical objects by means of kicking and were then exposed to a reinforcer containing only 2 of these components. This shift in component numerosity produced crying in 53% of the infants. Infants who cried in response to the reward shift evidenced no retention of the contingency 1 week later (Experiment 1) but did have excellent retention at 1 day (Experiment 2). In Experiment 3, a brief reactivation treatment alleviated forgetting at 3 weeks regardless of the presence of crying in response to the change in mobiles. An unexpected recency effect characterized the efficacy of the reactivation treatment. The results indicate that crying in response to the violation of a reward-expectation habit functions as an amnesic agent to produce accelerated forgetting.     

A failure to obtain magnetic discrimination in the pigeon

Six pigeons were trained on a multiple-concurrent schedule. During both multiple-schedule components, two response keys were available. In Component 1, responses to the left key were reinforced on a variable-interval 45-sec schedule, whereas responses to the right key were not reinforced. In Component 2, these contingencies were reversed. Following each reinforcer, the component next presented was chosen randomly with equal probability. The two components were differentially signaled by presentation of various stimuli during Component 1. Over the course of the experiment, these stimuli were various intensities of light, a noise, and various fluctuating and static magnetic fields. While subjects showed good discrimination of the light and noise stimuli, no stimulus control using the magnetic fields was obtained.     

Resistance to extinction: contingency termination and generalization decrement

We present an algebraic model of resistance to extinction that is consistent with research on resistance to change. The model assumes that response strength is a power function of reinforcer rate and that extinction involves two additive, decremental processes: (1) the termination of the reinforcement contingency and (2) generalization decrement resulting from reinforcer omission. The model was supported by three experiments. In Experiment 1, 4 pigeons were trained on two-component multiple variable-interval (VI) 60-sec, VI 240-sec schedules. In two conditions, resistance to change was tested by terminating the response-reinforcer contingency and presenting response-independent reinforcers at the same rate as in training. In two further conditions, resistance to change was tested by prefeeding and by extinction. In Experiment 2, 6 pigeons were trained on two-component multiple VI 150-sec schedules with 8-sec or 2-sec reinforcers, and resistance to change was tested by terminating the response-reinforcer contingency in three conditions. In two of those conditions, brief delays were interposed between responses and response-independent reinforcers. In both Experiments 1 and 2, response rate was more resistant to change in the richer component, except for extinction in Experiment 1. In Experiment 3, 8 pigeons were trained on multiple VI 30-sec, VI 120-sec schedules. During extinction, half of the presentations of each component were accompanied by a novel stimulus to produce generalization decrement. The extinction data of Experiments 1 and 3 were well described by our model. The value of the exponent relating response strength and reinforcement was similar in all three experiments.     

复合维生素添加剂对高温期淮北麻鸡生产性能和免疫功能的影响

目的:研究饲粮中添加不同水平的复合维生素添加剂对淮北麻鸡生产性能和免疫功能的影响及其相关性。方法:选取480只28周龄淮北麻鸡,随机分为4组,每组3个重复,每个重复40只鸡,饲喂在基础日粮分别添加复合维生素添加剂0(Ⅰ组,对照组)、100 mg/kg(Ⅱ组)、500 mg/kg(Ⅲ组)、1000 mg/kg(Ⅳ组),预试期2周,正试期8周。结果:与对照组比较,1)Ⅲ、Ⅳ组产蛋率比显著提高(P0.05),料蛋比显著降低(P0.05),蛋的受精率、孵化率及出雏率显著提高(P0.05);而Ⅱ组产蛋率、料蛋比、蛋孵化率和出雏率的变化不显著(P0.05);2)Ⅲ、Ⅳ组中血清免疫球蛋白A(Ig A)、免疫球蛋白M(Ig M)和补体C4含量显著提高(P0.05);而Ⅱ组中以上指标含量变化不显著(P0.05);3)Ⅲ、Ⅳ组血清超氧化物歧化酶活性和血清谷胱甘肽过氧化物酶活性及总抗氧化能力明显提高(P0.05),而Ⅱ组变化不明显(P0.05)。结论:饲粮中添加500~1000 mg/kg复合维生素添加剂能提高热应激条件下淮北麻鸡的生产性能、抗氧化能力和免疫功能。     

Self-control in the monkeymacaca fascicularis

Two experiments tested two cynomolgus monkeys’ self-control—choice of a longer, more delayed reinforcer over a shorter, less delayed reinforcer. In Experiment 1, subjects exhibited significant selfcontrol in a procedure in which reinforcer amounts and delays were held constant throughout a condition. In Experiment 2, subjects exhibited significantly greater sensitivity to variation in reinforcer amount than to variation in reinforcer delay in a procedure in which the reinforcer delay associated with the self-control alternative was adjusted until each macaque was indifferent between the two alternatives. Both experiments indicated that, in laboratory paradigms in which humans show self-control and pigeons and rats show impulsiveness, macaques show self-control. These results are inconsistent with the hypothesis that species differences in self-control are a function of language ability or of specific types of prior training. The results are consistent with the hypothesis that species differences in self-control are related to the ratio of brain size to body weight (a possible indicator of general cognitive ability) or to shared phylogeny.     

Differences in responding for sucrose and wheel-running reinforcement: Excitatory stimulus effects or inhibitory after-effects?

Previous research showed that sucrose and wheel-running reinforcement of leverpressing generate different response rate asymptotes. To investigate the basis of this difference, the present study assessed the role of inhibitory after-effects and excitatory stimulus effects on measures of responding in rats exposed to fixed-interval schedules that randomly produced either sucrose or wheel-running reinforcers. Different discriminative stimuli were associated with each reinforcer type. Inhibitory aftereffects and excitatory stimulus effects were assessed by the pattern of postreinforcement pauses and local response rates across the four different combinations of previous and upcoming reinforcer types: wheel-wheel, wheel-sucrose, sucrose-wheel, and sucrose-sucrose. Results showed that, regardless of the prior type of reinforcer, response rates were higher and pauses were shorter in the presence of a stimulus signaling sucrose reinforcement. This suggests that differences in response rate asymptotes generated by these qualitatively different reinforcers may have more to do with differences in excitatory stimulus effects than with inhibitory after-effects.     

Response rate is not an effective mediator of learned stimulus equivalence in pigeons

We explored response rate as a possible mediator of learned stimulus equivalence. Five pigeons were trained to discriminate four clip art pictures presented during a 10-sec discrete-trial fixed interval (FI) schedule: two paired with a one-pellet reinforcer, which supported a low rate of responding, and two paired with a nine-pellet reinforcer, which supported a high rate of responding. After subjects associated one stimulus from each of these pairs with a discriminative choice response, researchers presented two new clip art stimuli during a 10-sec FI: one trained with a differential reinforcement of low rate schedule (DRL) after the FI and the other trained with a differential reinforcement of high rate schedule (DRH) after the FI. Each of the stimuli that were withheld during choice training was later shown to see if the choice responses would transfer to these stimuli. The results suggest that response rate alone does not mediate learned stimulus equivalence.     

The relation of multiple-schedule behavioral contrast to deprivation,time in session,and within-session changes in responding

Pigeons' keypecking was reinforced by food on baseline schedules of multiple variable interval (VI) x VI x and on contrast schedules of multiple VI x VI y. Deprivation of food was varied by maintaining subjects at 75%, 85%, and 95% (+/- 2%) of their free-feeding weights. Positive and negative behavioral contrast were observed. The size of the contrast was not systematically altered by changes in deprivation. Positive and negative contrast were both larger later in the session than they were earlier. Within-session decreases in responding were steeper for the baseline than for the contrast schedules for positive contrast. Within-session decreases were steeper for the contrast than for the baseline schedules for negative contrast. These results were predicted by the idea that different amounts of habituation to the reinforcer during the baseline and contrast schedules contribute to behavioral contrast. The results show that contrast occurs under conditions that reduce the effect of the following component. The results support the assumption that positive and negative contrast are produced by symmetrical theoretical variables.     

The effects of child sexual abuse in later family life; mental health, parenting and adjustment of offspring

OBJECTIVE: To investigate links between child sexual abuse (occurring before 13 years), later mental health, family organization, parenting behaviors, and adjustment in offspring. METHOD: The present study investigates a subsample of the Avon Longitudinal Study of Parents and Children an ongoing study of women and their families in the area of Avon, England. A sample of 8292 families met inclusion criteria for identifiable family type and completed self-report data on prior sexual assault. Further data were collected on life course variables, socioeconomic variables, psychological well-being, relationship quality, parent-child relationship quality, and children's adjustment. RESULTS: After adjustment for other childhood adversity, prior child sexual abuse was associated with a range of outcomes in adulthood, including current membership of a nontraditional family type (single mother and stepfather) poorer psychological well-being, teenage pregnancy, parenting behaviors, and adjustment problems in the victim's later offspring. The relationship of child sexual abuse with aspects of the parent-child relationship in later life and with the offspring's adjustment difficulties were mediated in part by mother's mental health--chiefly anxiety. CONCLUSION: Findings indicate that child sexual abuse has long-term repercussions for adult mental health, parenting relationships, and child adjustment in the succeeding generation.     

The nature and determinants of spatial retreat in the pigeon between periodic grain presentations

Pigeons were exposed to fixed-time and fixed-interval schedules that ranged from 30 to 960 sec. The probability of a subject’s location in the rear of the chamber (away from the reinforcer dispenser) peaked during the postreinforcer period, and was referenced to proportional time between reinforcers. Increasing the interreinforcer interval generally increased time in the rear. In some sessions (Experiment 1), location in the rear produced an explicit stimulus change (altered the color and intensity of lights, i.e., time-out); this change increased time spent in the rear without affecting its temporal locus or its relation to the interreinforcer interval. During Experiment 2, a keypeck (near the reinforcer site) produced the explicit stimulus change used in Experiment 1. The characteristics of keypeck time-out resembled those of movement to the rear of the chamber (with and without an explicit stimulus change), suggesting that movement away from the reinforcer site is functionally homologous to keypeck time-out.     

Incentive learning and the motivational control of instrumental performance by thirst

The role of incentive learning in instrumental performance following a shift in the degree of water deprivation was analyzed in three experiments. In Experiments 1A and IB, rats trained to perform an instrumental action reinforced with either sucrose or maltodextrin solutions when in a high-deprivation state were subsequently shifted to a low-deprivation state and tested in extinction. This within-state shift in water deprivation reduced instrumental performance only when the animals had been exposed to the reinforcer in the low-deprivation state prior to instrumental training. In Experiment 2, a concurrent training procedure was used to assess whether the change in the value of the reinforcer brought about by preexposurewas mediated by the contingency between the instrumental action and the reinforcer. Preexposure to the reinforcer under the low-deprivation state produced a selective reduction of the performance of the action upon which it was contingent during training when testing was conducted in extinction following a shift from the high- to the low-deprivation state. These experiments provide evidence that animals have to learn about the incentive value of a reinforcer in a particular motivational state through exposure to the reinforcer in that state.     

Effects of response effort on self-control in rats

Five rats served as subjects in an experiment that examined the effect of increasing response effort on self-control (choice of a larger, more delayed reinforcer over a smaller, less delayed reinforcer). The rats made significantly more self-control choices as the force required to respond on each lever increased from 0.1 to 0.8 N. As the force required to press the levers increased to 1 N and then began to decrease, some of the rats stopped responding. For those rats that continued to respond, self-control tended to decrease. The results suggest that increasing the required response force can increase selfcontrol choices, as long as the required response force is low enough that some responding occurs.     

Blocking despite changes in reinforcer identity

Rats were trained on a discriminated operant barpressing task according to a standard blocking design. In some conditions, the reinforcer was changed between the pretraining and compound conditioning phases; for other conditions, the reinforcer remained the same across phases. In three separate experiments using both between- and within-subject designs, strong blocking effects occurred regardless of the change in the reinforcer. In a fourth experiment, a multiple schedule of reinforcement was used in which response-independent reinforcers were superimposed on the schedule of response-contingent reinforcers. The degree of response suppression caused by the free reinforcer was greater when the free reinforcers were the same as the response-contingent reinforcers than when they were different. The role played by the reinforcer identity in contingency experiments thus appears to be different from the role it plays in blocking experiments.     

Title I funded preschools as a developmental context for children’s play and verbal behaviors

This study examined changes across the school year in the play and verbal behavior during center based activities of 283 children in 22 public school preschool classrooms, funded through Title I. Using a time sampling method, observations of children in classroom settings were conducted twice during the preschool year. Repeated measures multivariate analyses of variance revealed that: (1) children were involved most in parallel play activities, and the amount of parallel play increased across the year; and (2) associative and cooperative play decreased. This pattern of behavioral change was present in 15 of the 22 classrooms. Conditional probability analyses indicated that associative play was an important context for verbalizations directed to both teachers and peers. At the time of each observation children played and talked with their peers most. We obtained one interaction effect between gender and time—the amount of talk from girls to teachers increased over the school year, whereas boys talked less to teachers over time. Classrooms were staffed by a certified teacher and an assistant and uniformly rated quite high on the Early Childhood Environment Rating Scale. This research demonstrates that public school preschools are funded and staffed appropriately, but that more attention could be paid to facilitating play and verbal interactions that might be important for later school success.     

Linkage between teen mother’s childhood adversity and externalizing behaviors in their children at age 11: Three aspects of parenting

Background: Experiences of childhood adversity are consistently associated with compromised behavioral health later in life. Less clear is the intergenerational influence of maternal childhood adversity on developmental outcome in children. Completely unknown are the mechanisms linking teen mother’s childhood adversity to child developmental outcomes.Objective: The present study tested whether aspects of parenting (parenting stress, physical discipline, and disagreement with grandparents) served as the pathways between teen mother’s childhood adversity and the externalizing behaviors of their offspring at age 11, by gender.Participants and setting: Data were from a longitudinal panel study of teen mothers and their children, the Young Women and Child Development Study (N = 495; 57% male).Methods: The pathways from teen mother’s childhood adversity to their offspring’s externalizing behavior were tested by two subscales: rule-breaking behavior and aggressive behavior. In addition, multiple-group analysis was examined for potential gender differences.Results: Teen mother’s childhood adversity was positively associated with greater use of parenting stress (β = 0.16, p < .01) and physical discipline (β=0.11, p < .05). In addition, parenting stress, physical discipline, and disagreement with grandparent were all associated with increased rule-breaking and aggressive behaviors in children. Multiple group analysis revealed that the path between physical discipline and externalizing behavior differed by gender, with the path only significant for girls.Conclusions: These findings have implications for early intervention efforts that emphasize the need to intervene with children and parents, particularly helping teen mothers gain knowledge and skills to offset the impact of their experiences of childhood adversity on their parenting behaviors.     

A Qualitative Analysis of the Immediate and Short-term Impact of an Environmental Interpretive Program

This study utilized qualitative measures to further understand if an environmental interpretive experience can enhance an environmental ethic. A discursive approach to emergent design was used to generate grounded theory (Strauss & Corbin, 1990). In the methods used, the phenomenological data gathered during the study directed the design of each step of the research as it evolved. Twenty-four 4th graders were randomly selected from three classes from a rural town in southern Indiana (USA). These students participated in a field trip to a US Forest Service site near their school district. Methodologies utilized in this program included ranger-led discussions, facilitated explorations, and nature 'games'. The data was collected through post interviews (1 week following treatment) and post post interviews (4 months after program). The findings indicated that the environmental interpretive program had a strong positive impact on students' affect toward the resource site. The findings also indicated retention of game mechanics and the content imbedded in these games. Cognitive and behavioral impacts were limited.     

Adult male--infant interactions among monkeys living in nuclear families.

Adult male rhesus monkeys were housed in nuclear families containing adult female mates, offspring, and other infants and adults. Behaviors exhibited by the adult males were recorded 4 days per week over a 37-month period; in interactions involving other monkeys, the identity and the responses of those participants were also recorded. The results indicated that, although adult males were less active and more stable in their behavioral levels than mates or offspring, they clearly distributed both initiates and responses differently to male offspring, female offspring, mates, and both infant and adult monkeys from other families. These results suggest that adult males have the potential to play more important roles in the social development of infants than had been previously suspected on the basis of field data. Implications for human father-infant interactions are discussed.     

English usage in daily life by Turkish students between 15–19 years of age: a scale development study

The purpose of this study is to develop a valid and reliable scale to assess the level of English usage in daily life by students between 15 and 19 years of age, and to compare these students’ scale scores according to their achievement levels in an English course. Five hundred and ninety-five participants were randomly selected from a universe. Exploratory factor analysis results indicate that the scale has a two-factor structure, which explains 50.1% of the total variance. Exploratory factor analysis is validated by confirmatory factor analysis (NNFI: 0.97; CFI: 0.97; GFI: 0.87; AGFI: 0.84; RMSEA: 0.07; and Standardized RMR: 0.05). Cronbach Alpha coefficients for Factor 1 and Factor 2 were calculated as 0.90 and 0.86, respectively. Test–retest reliability coefficient of the scale is at the expected level (r: 0.86, p<0.001). Item discrimination results indicate that the upper 27% of participants have higher mean rank scores for each item on the scale and on the two factors, and that this difference is significant at the 0.01 level. Results of the study show that students’ level of English usage in their daily life is low, and that the students who use more English in their daily life have a higher achievement level in the English course.     

A Differential Diagnosis of Low- and Average-Academic Ninth Grade Male Students

The study is an examination of the environmental forces and curriculum involvement in open and closed classroom settings. Fifteen Ss from three classrooms were each observed once in the closed setting (specific assignment given) and once in the open setting (free choice environment). This process yielded thirty, 10-minute specimen records which were analyzed through a behavioral classification system (Environmental Force Units). The study found that behavior in the open setting was characterized by: a.) more social interaction, b.) more interaction where peers lead each other into activities, and c.) less “casual exchange” behavior. There was a strong tendency (not significant) for more time to be spent on curriculum in the closed setting and more social interaction surrounding curriculum in the open setting.     

Choice and percentage reinforcement in pigeons

Pigeons responded on a two-key concurrent chains choice procedure with the same level of percentage reinforcement on each key. During the initial links, a choice response on either key occasionally produced a conditioned reinforcer—which on one key was associated with a 15-sec, and on the other key with a 30-sec, interreinforcement interval—or an extinction stimulus. In Part 1, the initial links were equal. With successive decreases in the probability of a reinforcer, choice shifted from preference for the 15-sec terminal link toward indifference. In Part 2, the initial links were unequal and were arranged so that the shorter initial link preceded the 30-sec terminal link. At a high probability of a reinforcer, the pigeons again preferred the 15-sec terminal link. However, at a low probability, the pigeons reversed and preferred the alternate key. It was concluded that the conditioned reinforcers tended to become functionally equivalent at a low probability of a reinforcer, despite the nominally different interreinforcement intervals, with the result that choice was then modulated by the relative size of the initial links. The data are inconsistent with the view that choice and the strength of conditioned reinforcers are isomorphic with the reduction in delay to reward correlated with terminal link stimuli.