Force and rate relations in responding during variable-interval reinforcement

Four rats responded on one-minute variable-interval schedules with several variations in peak-force of response required for food reinforcement. Measures of peak force and rate were taken for the responses, which were the downward exertions of force against a static force-transducing operandum. The analysis distinguished responses, a generic class of measured behavior, from criterion responses, an operationally specified subclass required for reinforcement. Absolute rate of response showed no systematic change, but the rate of responses meeting a newly required criterion of peak-force invariably increased through changes in the absolute rate of response, the relative-frequency distributions of peak force, or some combination of both. The relative frequency of responses meeting an elevated force criterion during variable-interval reinforcement exceeded that maintained with the same criterion with continuous reinforcement. The requirement of more effortful responding for reinforcement does not necessarily reduce response rate. Conformity of the behavior to the requirement for reinforcement is the salient effect.     

Behavioral contrast as a function of the temporal location of reinforcement

Pigeons were trained on a multiple variable-interval variable-interval schedule of reinforcement. One component was then changed to a variation of a fixed-interval schedule in which the same rate of reinforcement was obtained as previously but the location of the reinforcer was fixed within the component. The effects of different temporal locations were compared. An increase in response rate for the unchanged variable-interval component (behavioral contrast) occurred when the reinforcer was located in the middle or at the end of the FI component, but response suppression occurred when it was located at the beginning of the component. The pattern of results cannot be explained by any previous theories of contrast. The overall response rates, and the pattern of local rates within the components, were consistent with the hypothesis that the major determinant of the contrast effect was the transition to a lower reinforcement rate following the unchanged component.     

Stimulus control of differential-reinforcement-of-low-rate responding

Five pigeons were given single-stimulus training on an 8-sec differential-reinforcement-of-low-rate schedule followed by steady-state generalization training using 12 wavelength stimuli. Three birds had a high percentage of reinforced responses on the training schedule and flat generalization gradients of total responses. The birds with fewer reinforced responses had much steeper generalization gradients. Generalization gradients plotted as a function of both stimulus wavelength and interresponse time showed that for most birds, stimulus control was restricted to responses with long interresponse times. Responses with very short interresponse times were not under stimulus control and there was some evidence of inhibitory control of short interresponse times. Interresponse-times-per-opportunity functions, plotted as a function of stimulus wavelength, showed that stimulus wavelength controlled the temporal distribution of responses, rather than the overall rate of response. The data indicate that the differential-reinforcement-of-low-rate schedule generates several response categories that are controlled in different ways by wavelength and time-correlated stimuli, and that averaging responses regardless of interresponse-time length obscures this control.     

Effects of signals preceding and following shock on baseline responding during a conditioned-suppression procedure

Long-Evans rats were exposed to a succession of conditioned-suppression procedures involving pairings of (1) signal-shock, (2) shock-signal, and (3) a signal-shock-signal sequence in which first and second signals were at first physically identical. Traditional suppression of food-reinforced responding was obtained under the signal-shock arrangement, and exposure to the shock-signal sequence resulted in conditioned enhancement of responding during the signal. The signal-shock-signal condition reliably suppressed responding during the first signal, but produced no differential effect on response rate during the second signal. Baseline responding was least changed from preshock rates under the signal-shock-signal procedure, but baseline rate was considerably reduced under the signal-shock and shock-signal arrangements, the latter yielding most substantial reductions. A second experiment indicated that the magnitude and direction of changes in baseline responding reported in Experiment I were not confined to cases in which the first and second signals in the signal-shock-signal arrangement were physically identical. It is suggested that the major effects of the conditioned-suppression procedure on response rate might not be confined to presentations of the signal.     

The effects of massage velocity on heart rate and heart rate variability in healthy infants: A randomized crossover study

BackgroundInfant massage, in which mothers stroke their infant’s skin slowly and gently, can cause pleasant sensations in the infant that can be affected by the velocity of massage. However, the massage velocity at which infants feel the most pleasant sensations remains unclear.ObjectiveTo investigate the effects of massage velocity on heart rate (HR) and HR variability (HRV) in healthy infants.MethodTwenty-two infant-mother dyads two to seven months of age were recruited. Mothers stroked their infant’s skin at three massage velocities (5.0, 7.5, and 10.0 cm/s) in a randomized order for 15 min. The rhythm of massage velocity was calculated according to the length of three body areas. The massage velocity of the mothers was regulated using a metronome. HR and HRV (high frequency [HF] and low frequency [LF]) were measured at rest and during massage for each velocity. The effects on pleasantness were evaluated using percent change in median baseline value compared with median values for the three massage velocities. Statistical analysis was performed using analysis of variance mixed effect models to exclude “period” and “carryover” effects during massage.ResultsWhen measuring HF, massage (7.5 cm/s) caused a significant increase in pleasantness compared with 10.0 cm/s (p = 0.04). The HR and LF/HF ratio were not significantly changed between velocities.ConclusionResults of this study suggested that a massage velocity of 7.5 cm/s was the most pleasant for infants. Future research should investigate the relationship between an infant massage by optimal velocity and infant development in longitudinal studies.     

亲子间科技干扰与青少年网络人际关系成瘾：有调节的中介模型

对1353名高中生进行问卷调查,探究亲子间科技干扰与青少年网络人际关系成瘾之间的关系,相对剥夺感的中介作用及内在觉知的调节作用,结果表明：（1）亲子间科技干扰正向预测青少年网络人际关系成瘾;（2）相对剥夺感是亲子间科技干扰与网络人际关系成瘾之间的中介变量;（3）亲子间科技干扰与网络人际关系成瘾的间接效应前半段受到内在觉知的调节。因此,亲子间科技干扰和网络人际关系成瘾之间存在有调节的中介效应。     

汉语学龄前儿童主、宾关系从句认知特点及语义因素效应的研究

关系从句是人类语言领域句法结构较为复杂的句式,汉语3～5岁儿童是否具有加工关系从句的认知能力,以及该能力是否受句法结构和语义因素的影响,成为该领域当前研究的热点。本研究选取120名3～6岁学龄前儿童,以汉语主、宾关系从句为研究材料,通过操纵从句中核心名词的生命性格局对上述问题进行了考察。结果显示：(1)汉语领域内,3～4岁儿童基本上具备了理解句式较为简单的关系从句的能力;(2)5～6岁左右的儿童基本上具备了利用语义因素辅助关系从句加工的能力。总之,汉语学龄前儿童具备了加工关系从句的认知能力,且高年级儿童可以利用语义因素辅助从句加工。     

A comparison of picture and GIF-based preference assessments for social interaction

Researchers have recently begun to evaluate video-based preference assessments; however, only two studies have evaluated the efficacy of this preference assessment modality in assessing preference for social interactions. Four individuals diagnosed with autism spectrum disorder who could not match pictures or graphic-interchange-format images (GIFs) of social interactions to in vivo interaction participated. We compared picture and GIF-based paired-stimulus preference assessments for social interaction and evaluated the preference assessment hierarchies by conducting a concurrent-operant reinforcer assessment including all social interactions. The GIF-based preference assessment produced similar hierarchies to the reinforcer assessment for all participants, whereas the picture-based preference assessments produced similar hierarchies to the reinforcer assessment for 2 of 4 subjects. Additionally, we conducted a modality preference assessment in which we evaluated participants' preference for viewing GIFs or pictures of social interactions, and found that 3 out of 4 subjects displayed a preference for GIFs.