Comparison of yes-no and latency measures of auditory intensity discrimination.

Rats discriminated auditory intensity differences of sinusoids at 3.0 kilohertz in a go/no-go signal detection procedure. Responses to the signal (hits) were reinforced with electrical brain stimulation, and misses produced a brief timeout. On intermixed noise trials, withholding of responses (correct rejections) was reinforced, and false alarms produced the time-out. In two test conditions, the signal was either the louder (100 decibels) or softer (90, 93, 96, or 99 decibels) of the pair of intensities presented within a set of trials. Each animal was first trained with signal value louder or softer, and reversed for the second condition so that the former noise value served as signal. Hits showed shorter latencies than false alarms, regardless of the relative intensity of signal and noise, and the magnitude of differentiation was proportional to signal-noise separation. Both hits and false alarms showed longer latencies as the discrimination became more difficult. Isosensitivity contours derived from the latencies showed close similarity across conditions; in comparison, the yes-no measure of detectability, d', showed greater variability. The similarity of latency differentiation across louder and softer signal conditions supports a detection model in which the observer's judgment is controlled by the distance of sensory effect from criterion on each trial, as opposed to the loudness of the tones per se.     

Acceleration and suppression of rats' responding to avoid foot shock and tail shock

Signalled response-independent shocks were superimposed on rats' wheel-turn responding to avoid shock administered to their feet through a grid floor or to their tails through fixed electrodes. In Experiment I, a tone paired with response-independent foot shock increased responding in three of four rats; a tone paired with tail shock increased responding in only one of four rats and suppressed responding in two rats. In Experiment II, a tone presented randomly with respect to response-independent shock had no reliable effect on responding to avoid foot shock or tail shock. In Experiment III, tail shock and foot shock were compared in a within-subject design while the temporal pattern of responding during conditioned stimuli was recorded. Responding during the conditioned stimulus preceding foot shock was characterized by initial suppression of responding at tone onset, followed by increased responding just before response-independent shock. Responding was suppressed throughout the conditioned stimulus preceding tail shock. Foot shock elicited bursts of responding, but tail shock did not.     

The usefulness of distinguishing between a defensive and a nondefensive external locus of control

The study's purpose was to determine whether a distinction can be made between individuals adopting an external locus of control as a defense and those adopting the orientation because it reflects their life experience. It was hypothesized that the two groups differ in the amount of personal responsibility they accept for task outcomes. Internals and externals were identified and then further designated as high or low in action taking. Among externals, a high action-taking score implied defensiveness. Subjects randomly received either success or failure feedback on a presumed task of interpersonal sensitivity. Defensive externals varied their causal attributions as a function of outcome, whereas nondefensive externals did not (p < .05). The distinction between defensive and nondefensive external control was thus supported.     

Parameters affecting the maintenance of negatively reinforced key pecking

Three negative reinforcement experiments employing a key-peck response are described. In Experiment I, pigeons shocked on the average of twice per minute (imposed condition) could produce, by pecking a key, an alternate condition with correlated stimuli. Delayed shocks were added, across sessions, to the alternate condition until pecking stopped. Two of three pigeons continued to peck despite a 100% increase in shock frequency. In Experiment II, pigeons were shocked in the imposed condition four times per minute. The postresponse delay to shock was held constant by delivering, in the alternate condition, the next shock, or the next two, three, or four shocks from the imposed-condition shock schedule. All three subjects continued to peck with no change in delay to the first two postresponse shocks but with a 75% reduction in shock frequency. In Experiment III, a response produced an immediate shock followed by a shock-free period. Three of four subjects continued to respond despite reduced delay to shock. Delay-to-shock or shock-frequency reduction was sufficient to maintain key pecking, but neither was necessary. The conditions that negatively reinforce the pigeon's key peck were similar to conditions that negatively reinforce the rat's bar press.     

不同月龄小鼠行为训练与脑突触蛋白的相关性研究

不同年龄动物在各种行为实验中表现出学习记忆能力不同。一般地说,动物进入中年期以后,记忆保持力(retention)随年龄增长而下降。有关衰老性记忆障碍与脑内神经细胞变化的相关性已有大量观察记载,但中、幼年阶段的记忆力差异及其脑内突触机制     

A six-month follow-up of adolescents' sexual risk-taking,HIV/AIDS knowledge,and attitudes to condoms

A follow-up study was conducted to investigate change in sexual behaviour, knowledge about HIV/AIDS transmission, and attitudes to condoms over a 6-month period in a sample of late-adolescent students. The study also obtained subjective reports of HIV/AIDS-relevant change. Overall there was a decrease in sexual risk-taking behaviour with casual partners but no change occurred in sexual behaviour with regular partners, knowledge about HIV/AIDS, attitude towards condoms, or intention to use a condom on next sexual encounter. Examination of individual data revealed that, for some adolescents where behavioural change had occurred, this was in the direction of less safe sex. There were few self-reports of change in sexual behaviour, intention to take precautions against HIV/AIDS, or concern about HIV/AIDS over the preceding 6 months. Subjective reports of behaviour change did not correspond with reports of actual behaviour. Low rates of behaviour change are attributed to the failure of adolescents to personalize the threat of AIDS and to their trust in the safety of sex with a regular partner as well as to the lack of relevance of HIV/AIDS education campaigns to this group.     

AN ANALYSIS OF ERROR-CORRECTION PROCEDURES DURING DISCRIMINATION TRAINING

Mechanisms involved in error-correction procedures during behavioral acquisition were examined. Seven developmentally delayed subjects participated in match-to-sample discrimination training, consisting of three conditions arranged in a multielement design. Correct responses in all conditions were followed by praise and either food or pennies. In the baseline condition (differential reinforcement), an error produced no consequences. In the practice condition, an error was followed by repetition of the trial until a correct response occurred. In the avoidance condition, an error was followed by additional trials consisting of irrelevant stimuli; this condition separated the effects of repeated exposure to the same task from those of negative reinforcement, both of which existed in the practice condition. All 7 subjects made noticeable progress in the baseline condition. However, 5 of the 7 performed better in one of the error-correction conditions: 2 performed better in the practice condition, and 3 performed better in the avoidance condition. These data indicate that error-correction procedures may serve multiple functions and suggest that the practice requirement in this study included both avoidance and stimulus control components. More generally, the data indicate that additional control procedures should be included in acquisition studies to identify the relevant behavioral mechanism(s).     

Standardized and flexible batteries in neuropsychology: An assessment update

This article summarizes current literature relevant to commonly used tests and test batteries in clinical neuropsychology. The first section contains a discussion of the philosophy and relative advantages of standardized and flexible battery approaches in neuropsychology. The second contains historical background and a literature review of the two major standardized test batteries: the Halstead-Reitan and Luria-Nebraska. The third section includes reviews of tests that are frequently used in the flexible battery approach. Various tests of intellectual functioning, attention, memory, language, and spatial analyses are critiqued in this section. Contributions of the process approach are noted. The article ends by underscoring the need for continued research into the nature of neuropsychological measures and the abilities they assess.     

Behavior analysis/modification for everyone

This paper presents a very brief overview of people's attempt to understand and change behavior and shows how behavior analysis is different from these views. The importance of everyone knowing and using behavioral principles in their everyday life is stressed and the opposition to a behavioral approach is discussed. The aims of the organization called Behavior Analysis/Modification in the Regular Classroom is presented and some steps that this organization is following in an attempt to help to disseminate the knowledge and use of behavioral principles in the schools is presented.     

Interresponse-time punishment: a basis for shock-maintained behavior.

Lever pressing of squirrel monkeys postponed brief electric shock according to a free-operant shock-postponement procedure. Pressing also produced shock with a probability proportional to the duration of the current interresponse time in some conditions, or to the fifth ordinally-preceding interresponse time in others. These conditions provided equal frequencies and temporal distributions of response-produced shocks either contingent on or independent of the current interresponse-time duration, respectively. Shock delivered contingent on the current interresponse-time duration resulted in shorter mean interresponse times and higher overall response rates that shock delivered independent of the current interresponse time. In subsequent conditions, response-produced shocks were sufficient to maintain responding following suspension of the postponement procedure only when those shocks were contingent on the current interresponse time. Presenting shock independent of the current interresponse time, conversely, suppressed response rate and ultimately led to cessation of responding in the absence of a conjoint shock-postponement procedure. These results demonstrate interresponse-time punishment in the absence of any indirect avoidance contingencies based on overall shock-frequency reduction, and strongly support similar interpretation at the more local level of shock-frequency reduction correlated with particular interresponse times. Differential punishment of long interresponse times also provides both an a priori basis for predicting whether a schedule of shock presentation will maintain or suppress responding and a framework for interpreting many of the functional relations between overall response rate and parameters of consequent shock presentation. Finally, these results and others indicate the importance of response-consequence contiguity above and beyong any notion of noncontiguous contingency in the control of behavior.