Successive positive contrast in one-way avoidance learning

The main finding of these experiments was a positive contrast effect in one-way avoidance learning. Experiment 1 showed that increasing safety time during one-way avoidance training led to improved performance, surpassing that of a control group that had received the high reward (safe time) from the beginning of training. Experiment 2 showed that a similar positive contrast effect occurred when the time spent in the danger compartment before the onset of the warning signal was shortened. These results suggest that time spent in a safe context acts as a reinforcer of the avoidance response; however, its incentive value depends not only on its duration, but also on the length of the time spent in the danger compartment before the onset of the signal. Overall, results also suggest that the avoidance response is a mixture of flight (motivated by fear) and approach (to a safe place) behaviour. The specific weight of the flight or approach component may be a function of the time and the amount of activation of each emotional state (fear or relief) due to opponent homeostatic compensatory processes that occur in the danger and safe compartments during one-way avoidance learning.     

Successive negative contrast in one-way avoidance learning in rats

In three experiments, successive negative contrast was examined in one-way avoidance learning. Reward magnitude in first (pre-shift) and second (post-shift) phases was manipulated by time spent in the safe compartment. Experiment 1 demonstrated that when time in the danger compartment was held constant, a group shifted from a large reward--30 sec spent in the safe compartment--to a small reward--1 sec--showed poor performance and longer response latency than a group conditioned with the small reward in both phases. Experiment 2 replicated this effect with a less intense shock and also demonstrated that a group shifted from large to small reward performed more poorly than a group exposed to large reward--30 sec--in both phases. Finally, Experiment 3 showed that changes in intertrial interval, defined as total time spent in the safe compartment and the danger compartment before the onset of the warning signal, were not responsible for this contrast effect. These results suggest that time spent in a safe place can act as appetitive incentive during one-way avoidance learning.     

Experimental evaluation of matching via a commercially available basketball video game

Many recent nonlaboratory-based quantitative analyses of behavior have relied on archival competitive sporting data. However, the ratio-based reinforcement schedules in most athletic competitions and the correlational nature of archival data analyses raise concern over the contributions of such findings to the behavior analytic literature. The current experiment evaluated whether matching in a human operant paradigm would approximate matching observed in nonlaboratory-based sports data. To this end, we used in-game attributes to parametrically manipulate 2- and 3-point shooting in a commercially available basketball video game. The behavior of 6 of 9 participants conformed to the generalized matching equation. These results suggest matching in sporting contexts may be a product of restricted nonindependent concurrent random-ratio schedules. Implications of this experiment, including those in applied behavior analysis and potential influence on gamification, are discussed.     

A comparison of simulated one-way and shuttle avoidance in an automated apparatus

The fully automated shuttle box employed in two experiments permitted the comparison within one apparatus of performance under a simulated one-way condition and the usual shuttle condition. Animals in the simulated one-way condition always ran from a white compartment into a black compartment, but alternated their direction of locomotion, as did the shuttle animals. In both experiments, animals run under the simulated one-way condition showed superior per cent avoidance performance relative to the shuttle animals. The results were compared with those obtained in other one-way avoidance and shuttle studies.     

Relative time in dangerous and safe places influences one-way avoidance learning in the rat

This paper reports three experiments on one-way avoidance learning in rats which examined the effect of time spent in the safe and dangerous compartments on acquisition, maintenance, and extinction of avoidance. In Experiment 1 time spent in safety was manipulated, and time spent in danger was held constant. Animals spending more time in safety needed fewer trials to reach the acquisition criteria and more trials to reach the extinction criteria; both effects became stronger as the required criteria for acquisition and extinction were increased. In Experiment 2 time spent in safety/danger was manipulated while holding the intertrial interval constant. Groups simultaneously spending more time in safety and less time in danger again needed fewer trials to reach the learning criteria. In Experiment 3 time spent in danger was manipulated, whereas time spent in safety was held constant. Groups spending less time in danger needed fewer trials to reach the learning criteria. These results indicate that the magnitude of the reinforcement or incentive value of the safety compartment is not a linear function of absolute time spent therein, but a function of the ratio between the length of time spent in safety and in danger.     

Deficient passive and one-way active avoidance acquisition following medial forebrain bundle lesions in rats.

Cathodal electrolytic lesions of the medial forebrain bundle (MFB) at posterior hypothalamic levels in male hooded rats produced a mild, transient hypodipsia and lowered jump thresholds to footshock. The lesions produced marked deficits in passive avoidance performance in a paradigm that paired discrete, linearly incrementing footshock intensities with contact of a water spout following 48 hr of water deprivation. Intraperitoneal injections of DL-5-hydroxytryptophan (75 mg/kg), the immediate metabolic precursor of serotonin, had no effect on the passive avoidance performance of either experimental or operated control subjects. Lesions of the MFB also resulted in deficient acquisition in a one-trial step-through passive avoidance paradigm not using motivation to drink and caused a severe acquisition deficit in a one-way active avoidance task. Lesions of the septal nuclei produced lowered jump thresholds but did not affect acquisition in the first passive avoidance task. The results are interpreted as indicating a lesion-induced deficiency in fear learning, independent of the serotonergic functions of the MFB.     

Brief escape from a dangerous place: The role of reinforcement in the rat's one-way avoidance acquisition

Five experiments are reported which attempt to eliminate two possible sources of reinforcement in one-way avoidance learning: a period of escape from aversive apparatus cues and the termination of the warning signal (WS). A “brief escape”/one-way avoidance procedure was developed to minimize the time rats spent away from the shock box. It was found that, although prolonged escape from shock box cues contributes to the acquisition rate of one-way avoidance, it is not essential for relatively rapid acquisition to occur. It was also found, in agreement with earlier evidence, that WS termination makes no discernible contribution to learning in the one-way situation. Thus, neither source of reinforcement appears to be necessary for acquisition. At this point, one may argue either that reinforcement is not necessary for rapid one-way avoidance acquisition [e.g., Bolles' 1972 species-specific defense reaction hypothesis (In G. H. Bower (Ed.), The psychology of learning and motivation: Advances in research and theory (Vol. 6). New York: Academic Press, 1972)] or that there are other sources of reinforcement. As an example of the latter approach, a consummatory stimulus reward hypothesis is advanced.     

Active avoidance performance in genetically defined mice

It has been concluded by several investigators that active avoidance performance in mice is primarily influenced or even determined by a single gene. The genetically defined strains C57BL/6 and BALB/c have provided evidence that an aberrant development of pyramidal cells and mossy fiber configuration in the hippocampus of BALB/c mice also is determined by a single gene. As a test of the generality of the single gene influence on avoidance learning, and to examine the relationship of the hippocampal defect to avoidance learning, adult male mice of the inbred progenitor strains C57BL/6ByJ and BALB/cByJ and their seven recombinant inbred strains were tested in a variant of the shuttle-box paradigm used in previous studies. BALB/c were found to acquire the avoidance response at a faster rate than C57BL/6, consistent with most earlier reports, but performances of the recombinant inbred strains failed to dichotomize about the progenitor strains. The rank order of performance scores for the recombinant inbred strains was different from that reported in previous studies. Thus the present data failed to support the interpretation of a single major gene influencing active avoidance learning. It is concluded that avoidance learning and performance cannot be considered as unitary variables and that the interaction of genetic with environmental factors, including the conditions of the specific testing situation, are important considerations in any interpretation of genetic effects. No relationship between the hippocampal lamination defect and avoidance performance was demonstrated.