Concurrent fixed-ratio and avoidance responding in the squirrel monkey

Squirrel monkeys maintained concurrent performances appropriate to a fixed-ratio schedule of food reinforcement on one lever and an avoidance schedule on a second lever. The overall rate of responding maintained by either schedule was not systematically affected when the other schedule was discontinued and its lever removed.     

Transfer of conditioned fear and avoidance: Concurrent measurement of arousal and operant responding

A reversal design was employed for the analysis of transfer of fear and avoidance through equivalence classes. Two 5-member equivalence classes (A1-B1-C1-D1-E1 and A2-B2-C2-D2-E2) were established. Then B1 and C1 were paired with shock (CS+) and served as S^Ds in avoidance training (B2 and C2 were trained as CS-/S^∆s for avoidance). Further avoidance training followed with D1 and E1 (as S^Ds) and D2 and E2 (as S^∆s), with the first presentation of each of these stimuli serving as the first transfer test. Afterwards, aversive conditioning contingencies were reversed: B2 and D2 were paired with shock and trained as S^Ds for avoidance, B1 and D1 were presented without shock (CS-/S^∆s). Transfer was tested again with C1, E1, C2 and E2. This reversal was implemented to allow for the within-subject replication of transfer effects upon changes in the function of only a subset of each class's elements. Avoidance (key presses) and conditioned fear (skin conductance and heart rate) were simultaneously measured. Results show a clear transfer effect for avoidance, with between- and within-subject replications. For physiological measures, transfer effects in the first test could only be imputed on the basis of group-based inferential statistical analysis. Evidence for between-subject replication was weaker, with only a limited proportion of participants meeting the individual criterion for transfer.     

Effects of learned helplessness training on instrumental heart rate control in humans

In Experiment 1, subjects who received feedback contingent on short interbeat intervals (relative to a baseline period) learned to accelerate their heart rates, but subjects who received noncontingent feedback did not. In Experiment 2, subjects who were exposed to noncontingent aversive noises later showed significant performance deficits on both an instrumental and a cognitive task. Attributional style predicted helplessness deficits on the cognitive but not the instrumental task. Experiment 3 demonstrated that experimentally induced helplessness interferes with biofeedback learning. Attributional style did not predict the occurrence of helplessness deficits in this context. Results are discussed in terms of the nature of biofeedback training and the range of behaviors that learned helplessness training affects.     

Electroencephalographic and blood pressure correlates of operantly conditioned heart rate in the restrained monkey

Each of four monkeys was trained to slow its heart rate and to speed its heart rate. Mean blood pressure was positively correlated with heart rate during speeding and during slowing. These correlations increased from early training to late training for all animals during slowing; however, they did not change during speeding. High voltage in the 8–14 Hz band of the EEG was correlated negatively with heart rate; however, the correlations were insignificant or low. The correlations between EEG changes and heart rate changes increased (became more negative) during the late phase of slow training but did not change reliably during speeding training. Baseline levels in all physiological functions changed as a function of stage of training. Response patterns during escape behavior indicate dissociation of heart rate and blood pressure, whereas response patterns during avoidance behavior show correlation of heart rate and blood pressure. The findings indicate that the physiological effects of heart rate slowing and heart rate speeding are different and not merely mirror images of one another.     

Autonomic concomitants of discriminative avoidance and punishment training in the monkey

TwoCebus albifrons monkeys were trained to press a back-lighted panel to postpone a brief electric shock to the tail using a Sidman avoidance schedule (SS = 40 sec, RS = 40 sec). After 25 training sessions, a discriminative schedule was introduced, with the Sidman avoidance continuing in the presence of one discriminative stimulus and punishment introduced in the presence of the other. The discriminative stimuli were colors on the panel. Discriminative training also involved 25 sessions, each with a random sequence of 6 avoidance and 6 punishment segments, with 30 sec intervals between the segments. Plantar skin conductance and heart rate were recorded along with the panel-pressing behavior. The two monkeys adjusted to the discriminative schedule quite differently from one another. One animal responded at a high level and avoided very well (during avoidance) but was punished frequently (during punishment). The other animal responded less frequently and received many shocks during avoidance but almost none during punishment. The animal that showed less ability to inhibit responding (and received about four times as many shocks overall) appeared to have discriminated better temporally in spacing its responses during avoidance training. The monkey whose panel-pressing behavior resulted in more shocks also tended to show a higher tonic level of autonomic arousal. However, within-animal differences in shock frequency (between avoidance and punishment) were not similarly related to autonomie arousal. The animal that received fewer shocks overall (but more during avoidance) showed greater arousal during punishment. The animal that received more shocks overall (but fewer during avoidance) showed no arousal differences between avoidance and punishment.     

Attention and cue-producing behavior in the monkey

Explicit cue-producing responses were employed to study attending behavior in the monkey. The subjects learned a discrimination based on compound stimuli, a vertical bar embedded on a red ground versus a horizontal bar on a green ground. On some trials only one of the two stimulus components was presented (red versus green or vertical versus horizontal bar), and the animals had the option of responding on the basis of the component presented or transforming it to the compound discriminanda by means of a cue-producing response. Analysis of the choice and cue-producing response behavior showed that (a) both monkeys acquired the discrimination between the compound cues solely on the basis of the color component, (b) mastery of this discrimination did not confer any "habit loading" (discriminative control) on the bar component, and (c) the monkey may prefer to respond on the basis of one component (color) even though it is capable of using both components equally effectively.     

Contact-free measurement of heart rate, respiration rate, and body movements during sleep

We describe a noncontact method for the ambulant measurement of basic sleep physiology parameters in humans, particularly for field studies involving sleep research and sleep disturbances. This method traces the body movements, respiration, and heart action of a person at rest or asleep on a bed, using four high-resolution force sensors installed under the bedposts. The recoil movement of the body at each heartbeat, known as the cardioballistic effect, as well as the lifting and lowering of the thorax, while breathing, causes very small shifts of the center of gravity of the bed and the subject. These shifts are reflected in the altering force distributions across the four sensors. Cardiac and respiratory parameters and the subject’s movement activity can be calculated from the sensor signals. Neither electrodes nor other kinds of transducers are in direct contact with the subject, which is the main advantage of this technique over conventional methods. Laboratory experiments were carried out to estimate validity and practicability. The method has been found to be adequate, especially for automated and unattended sleep-data collection over long periods of time.