Effect of monochromatic light on the behavior of the ctenophore Mnemiopsis leidyi (A. Agassiz, 1865)

Ctenophores are invertebrate, gelatinous predators that perform complex movements due to their numerous ciliary comb plates. We investigated the behavioral responses of the ctenophore Mnemiopsis leidyi A. Agassiz, 1865 to red, green, and blue lights of different powers and fluxes emitted by LEDs or lasers. White LEDs were used to mimic natural sunlight. When laser light was directed to the aboral organ, the animals tended to leave the illumination zone. The blue-light reaction was six times faster than the red-light reaction. The behavioral strategy of the animals changed significantly when their freedom of maneuvering was restricted. Typical locomotions were ranked according to the laser beam avoidance time from the beginning of exposure to going into darkness. The minimum reaction time was required for turning and moving the ctenophore, while moving along the laser beam and turning around required more time. Typical patterns of behavior of M. leidyi in the light flux were established using cluster analysis. Three preferential behavioral strategies were identified for avoiding laser irradiation: 1) body rotation; 2) shifting sideways; and 3) movement with deviation from the beam. The elementary ability of ctenophores to make decisions in situative conditions has been demonstrated.

The voluntary operant and the operant nature of volition: Three views

Many philosophers, psychologists, and lay folk associate volition with autonomy (actions are independent of an individual's environment) and free will (individuals originate their actions). Most behaviorists hold these views to be incompatible with behavior analyses. The present paper describes volition as interpreted by B. F. Skinner, Howard Rachlin, and Allen Neuringer. Skinner relates volition to positively reinforced operant behavior. That works because, like operants, voluntary actions are free, in the sense of not physically constrained; they affect their environments, often resulting in positive outcomes, and are sometimes unpredictable. Rachlin, while incorporating Skinnerian methods, interprets volition within his own Teleological Behaviorism framework. For Rachlin, reinforcement of an individual response is often incompatible with voluntary control, thereby disagreeing with Skinner. Responses are voluntary only when they are members of extended response patterns. Neuringer also begins with Skinner's operants, but argues that, under the control of reinforcing consequences, both voluntary actions and operant responses are sometimes predictable and other times "truly" unpredictable. Neuringer does not assume that environments determine voluntary actions, thereby disagreeing with Skinner and Rachlin. Taken together, the agreements and disagreements among these three behaviorists may help to shed light on the relationship between operants and volition.

Qualitative variations in delay discounting: A brief review and future directions

The discounting paradigm has been challenged by an increasing number of studies presenting qualitative variations in the individual discount function. Particularly, the subjective value of a loss does not necessarily systematically decrease with delay to the outcome. Qualitative variation refers to variations in shape rather than steepness of the discount function, such as positive discounting, zero discounting, unsystematic discounting, and negative discounting. Data from three previous studies were analysed in terms of qualitative variations observed in delay discounting patterns. Attention was also given to methods used and to the relationship between the results from the various levels of investigation. We found qualitative differences between discounting of monetary gains and losses on an individual level. While discounting of gains mainly took the form of conventional positive discounting, discounting of losses often took the form of zero discounting or unsystematic discounting. Further, there were more qualitative variations in discounting of both gains and losses among adolescents compared to adults. By examining verbal reports and single choices, we identified some of the rules and consequences involved in these delay discounting patterns. The different rules and consequences observed for the gain and loss scenarios, support that discounting of gains and losses may involve different combinations of reinforcing contingencies. These results point towards a possible way to explain the influences of qualitative variations in delay discounting.

Large-N Rat Data Enables Phenotyping of Risky Decision-Making: A Retrospective Analysis of Brain Injury on the Rodent Gambling Task

Decision-making is substantially altered after brain injuries. Patients and rats with brain injury are more likely to make suboptimal, and sometimes risky choices. Such changes in decision-making may arise from alterations in how sensitive individuals are to outcomes. To assess this, we compiled and harmonized a large dataset from four studies of TBI, each of which evaluated behavior on the Rodent Gambling Task (RGT). We then determined whether the following were altered: (1) sensitivity to overall contingencies, (2) sensitivity to immediate outcomes, or (3) general choice phenotypes. Overall sensitivity was evaluated using the matching law, immediate sensitivity by looking at the probability of switching choices given a win or loss, and choice phenotypes by k-means clustering. We found significant reductions in sensitivity to the overall outcomes and a bias toward riskier alternatives in TBI rats. However, the substantial individual variability led to poor overall fits in matching analyses. We also found that TBI caused a significant reduction in the tendency to repeatedly choose a given option, but no difference in win- or loss-specific sensitivity. Finally, clustering revealed 5 distinct decision-making phenotypes and TBI reduced membership in the “optimal” type. The current findings support a hypothesis that TBI reduces sensitivity to contingencies. However, in the case of tasks such as the RGT, this is not a simple shift to indiscriminate or less discriminate responding. Rather, TBI rats are more likely to develop suboptimal preferences and frequently switch choices. Treatments will have to consider how this behavior might be corrected.

On Response Strength and the Concept of Response Classes

Simon et al. (2020) argue that the concept of response strength is unnecessary and potentially harmful in that it misdirects behavior analysts away from more fruitful molar analyses. I defend the term as a useful summary of the effects of reinforcement and point particularly to its utility as an interpretive tool in making sense of complex human behavior under multiple control. Physiological data suggest that the concept is not an explanatory fiction, but strength cannot be simply equated with neural conductivity; interaction with competing behaviors must be considered as well. Decisions about appropriate scales of analysis require a clarification of terms. I suggest defining behavior solely in terms of its sensitivity to behavioral principles, irrespective of locus, magnitude, or observability. Furthermore, I suggest that the term response class be restricted to units that vary together in probability in part because of overlapping topography. In contrast, functional classes are united by common consequences; they vary together with respect to motivational variables but need not share formal properties and need not covary with acquisition and extinction contingencies.

Behavior, process, and scale: Comments on Shimp (2020), "Molecular (moment-to-moment) and molar (aggregate) analyses of behavior"

If we study the behavior of organisms, we must understand the ontological status of both "organism" and "behavior." A living organism maintains itself alive by constantly interacting with the environment, taking in energy and discarding waste. Ontologically, an organism is a process. Its interactions with the environment, which constitute its behavior, are processes also, because the parts of any process are themselves processes. Processes serve functions, and the function of a process must be part of its identity. A process, by definition, extends in time. Time is the fundamental and universal measure of behavior. All processes have the property of scale. Activities of an organism have parts that are themselves activities on a smaller time scale. Scale varies continuously, and behavior may be studied on as large or as small a time scale as seems necessary. When researchers refer to the "structure" of behavior, they refer to smaller-scale activities. Attaching a switch to a lever or key is convenient, but one should never confuse operation of a switch with a unit of behavior. Shimp's (2020) "molecular" measures are small-scale measures. The molecular view based on discrete events has outlived its usefulness and should be replaced by a multiscale molar paradigm.