A two-stage incentive mechanism for rebalancing free-floating bike sharing systems: Considering user preference

Free-floating bike sharing (FFBS) provides citizens with a flexible way for traveling. The operational performance of such systems is impacted by the imbalance problem of demand and supply. This paper proposes the first two-stage incentive mechanism to improve the service quality of FFBS. While inspired by the user-based rebalancing approach in station-based bike sharing (SBBS), our work is different from existing studies because location optimization is a new problem in FFBS and user preference is considered for the first time. We propose three mechanisms that are pick-up incentives, drop-off incentives, and two-stage incentives. When modeling users’ behavioral responses to incentive mechanisms, we think users prefer drop-off incentives to pick-up incentives, which is supported by a survey study. Each incentive offer is composed of a location and a price. To decide the suggested origin or destination, we first figure out the supply and demand of all valid locations based on Radiant Service Theory (RST) and then search the most problematic location comparing current inventory and future demand. The pricing scheme is modified Budgeted Procurement using Upper Confidence Bounds (BP-UCB). Simulation experiments validate the effectiveness of incentive mechanisms based on historical data from Capital BikeShare program. Results show that the service level of bike sharing systems can be significantly improved by three incentive mechanisms. The two-stage incentive mechanism unexpectedly shows no advantage over pick-up incentives. Sensitivity analysis further indicates that user preference will influence the ranking of two single-stage incentive mechanisms.     

“We will work for you” – Social influence may suppress individual food preferences in a communicative situation in dogs

The level of motivation (i.e. incentive power) is thought to be one of the most important factors affecting performance and learning in various tasks. We investigated whether reward quality has an effect on the performance of family dogs in a two-way object choice test in which they can find the hidden food by relying on distal momentary human pointing cues. In three experiments we varied (1) the type of food reward according to the subjects’ own preference; (2) the quality of the reward offered at the same time in the indicated and not-indicated locations; and (3) the order of the high or low quality rewards in consecutive sessions. In Experiment 1, we first tested whether dogs prefer one kind of reward over another. Then one group was tested with the ‘preferred’ food as reward in the indicated bowl, while dogs in the other group received the ‘non-preferred’ food as reward. We did not find any difference between the performance and choice latencies of the two groups. In Experiment 2 for the first group, the indicated bowl contained a piece of carrot and the not-indicated bowl was empty. In the second group the indicated bowl contained carrot, but the not-indicated bowl contained sausage. According to a preliminary preference test, most dogs prefer sausage over carrot invariably. After 20 trials, the two groups performed surprisingly similarly. There was no difference found between groups in the number of correct choices, incorrect choices and non-choices. However, the comparison between the first and last five trials revealed that subjects who found sausage when they chose the not-indicated bowl (did not follow the pointing) chose the non-indicated bowl significantly more often toward the end of their test session. In Experiment 3, each dog received two sessions with 12 pointing trials in each. For the first session, one group was rewarded with sausage and the other with carrot upon choosing the indicated bowl. In the second session, the indicated bowl contained dry dog food for both groups. We found that correct choices and response latencies did not change over two sessions in the ‘sausage’ group. In the ‘carrot’ group, the dogs chose faster in the second session, but their performance did not improve; in fact, they chose the not-indicated bowl more often than the indicated bowl. As a conclusion, we can say that reward quality had some effect on dogs’ choice behavior in these experiments. The drop in their performance was not drastic, taking into account the general refusal to eat one of the ‘rewards’ (carrot) during the preference tests and also during the test trials. It seems that incentive contrast may play a relatively minor role in dog-human social interactions. Appropriate reward quality can be very important in asocial problem solving tasks, but, when interacting with humans, following human signals may override the effect of changed incentive power.     

Equally attending but still not seeing: An eye-tracking study of change detection in own- and other-race faces

The present study aimed to investigate whether the faster change detection in own-race faces in a change blindness paradigm, reported by Humphreys, Hodsoll, and Campbell (2005) and explained in terms of people's poorer ability to discriminate other-race faces, may be explained by people's preferential attention towards own-race faces. The study by Humphreys et al. was replicated using the same stimuli, while participants’ eye movements were recorded. These revealed that there was no attentional bias towards own-race faces (analysed in terms of fixation order, number, and duration), but people still detected changes in own-race faces faster than in other-race faces. The current results therefore give further support for the original claim that people are less sensitive to changes made in other-race faces, when own and other-race faces are equally attended.     

Willingness to accept occupational change when offered incentives: Comparing full-time and part-time employees

The ability to deal with occupational change is becoming increasingly important. We hypothesized that individual differences determining preferences for specific types of mobility (i.e., global personality traits and uncertainty tolerance) and decisional factors theoretically derived from the theory of planned behaviour (e.g., desirability of change; subjective norms) would be associated with higher willingness to accept occupational change when incentives such as greater autonomy were offered. These hypotheses were tested in a questionnaire study with samples of full-time and part-time employees. We further expected employment situation to function as a moderator in this process. Overall, results of regression analyses confirmed the relevance of the core components of the theory of planned behaviour. In addition, we found decisional factors to be more closely linked to the outcomes of full-time employees than to those of part-time employees. We discuss the practical implications of our results in terms of how best to support employees in adapting to the increasing demands for occupational change.     

Scaling relative incentive value in anticipatory behavior

Papini and Pellegrini (Papini, M. R., & Pellegrini, S. Scaling relative incentive value in consummatory behavior. Learning and Motivation, in press) observed that, within limits, the level of consummatory responding of rats exposed to incentive downshifts in the concentration of sucrose solutions was similar when the ratio of test/training solutions was the same. For example, 32 → 4% and 16 → 2% downshifts (1:8 test/training ratios) lead to similar levels of consummatory behavior, despite differences in the absolute concentrations of the solutions involved in the downshift. This suggests the applicability of Weber’s law to spaced-trial, incentive-downshift situations. Experiment 1 extended these results to runway performance using food pellets as reward, and Experiment 2 to lever pressing performance, using an autoshaping procedure and sucrose solutions as rewards. The results conform well to the test/training ratio suggesting that Weber’s law is applicable to anticipatory behavior. A simple mathematical rule that can be easily incorporated into models based on linear operators describes the results of consummatory and anticipatory behavior experiments.     

Gender differences in the incentive salience of adult and infant faces

Facial appearance can motivate behaviour and elicit activation of brain circuits putatively involved in reward. Gender differences have been observed for motivation to view beauty in adult faces—heterosexual women are motivated by beauty in general, while heterosexual men are motivated to view opposite-sex beauty alone. Although gender differences have been observed in sensitivity to infant cuteness, infant faces appear to hold equal incentive salience among men and women. In the present study, we investigated the incentive salience of attractiveness and cuteness in adult and infant faces, respectively. We predicted that, given alternative viewing options, gender differences would emerge for motivation to view infant faces. Heterosexual participants completed a “pay-per-view” key-press task, which allowed them to control stimulus duration. Gender differences were found such that infants held greater incentive salience among women, although both sexes differentiated infant faces based on cuteness. Among adult faces, men exerted more effort than women to view opposite-sex faces. These findings suggest that, contrary to previous reports, gender differences do exist in the incentive salience of infant faces as well as opposite-sex faces.     

Where is the chocolate? Rapid spatial orienting toward stimuli associated with primary rewards

Some stimuli can orient attentional resources and access awareness even if they appear outside the focus of voluntary attention. Stimuli with low-level perceptual salience and stimuli with an emotional content can modulate attention independently of voluntary processes. In Experiment 1, we used a spatial cuing task to investigate whether stimuli that are controlled for their perceptual salience can modulate the rapid orienting of attention based exclusively on their affective relevance. Affective relevance was manipulated through a Pavlovian conditioning paradigm in which an arbitrary and affectively neutral perceptual stimulus was associated with a primary reward (i.e., a chocolate odor). Results revealed that, after conditioning, attentional resources were rapidly oriented toward the stimulus that was previously associated with the reward. In Experiment 2, we used the very same conditioning procedure, but we devaluated the reward after conditioning for half of the participants through a sensory-specific satiation procedure. Strikingly, when the reward was devaluated, attention was no longer oriented toward reward-associated stimuli. Our findings therefore suggest that reward associations rapidly modulate visual processing independently of both voluntary processing and the perceptual salience of the stimulus. This supports the notion that stimuli associated with primary rewards modulate rapid attention orienting on the basis of the affective relevance of the stimulus.     

Effect of motivation on academic fluency performance in survivors of pediatric medulloblastoma

It has been proposed previously that extrinsic motivation may enable survivors of childhood medulloblastoma to significantly improve aspects of neurocognitive performance. In healthy populations, enhanced motivation has been shown to promote academic fluency, a domain likely more relevant to the educational outcomes of pediatric medulloblastoma survivors than academic skill development. The present study investigates the effect of enhanced extrinsic motivation on fluent (i.e., accurate and efficient) academic performance in pediatric medulloblastoma survivors. Participants were 36 children, ages 7–18, who had completed treatment for medulloblastoma. Participants completed a neuropsychological battery that included administration of equivalent tasks on Forms A and B of the Woodcock-Johnson III Tests of Achievement. Half were randomly assigned to an incentive condition prior to the administration of Form B. Provision of a performance-based incentive resulted in statistically significant improvement, but not normalization of function, in performance on measures of academic fluency. No demographic, treatment-related, academic, neuropsychological, or self-perception variables predicted response to incentive. Findings suggest that academic performance of survivors may significantly improve under highly motivating conditions. In addition to implications for educational services, this finding raises the novel possibility that decreased motivation represents an inherent neuropsychological deficit in this population and provides a rationale for further investigation of factors affecting individual differences in motivational processes. Further, by examining effort in a context where effort is not inherently suspect, present findings also significantly contribute to the debate regarding the effects of effort and motivation on neuropsychological performance.     

Single, but not multiple pairings of sucrose and corticosterone enhance memory for sucrose drinking and amplify remote reward relativity effects

This study tested whether pre-training pairings of ingestion of a 32% sucrose solution and injection(s) of corticosterone (B) would enhance later ingestion in the absence of B, and whether these effects would carry over into later contrast-like effects when animals were subsequently shifted to 4% sucrose. Frequency-dependence of these pairings was also examined. Three groups of male Sprague-Dawley rats were adrenalectomized (ADX). A fourth group was sham ADX. Each ADX group received three presentations of sucrose and B (666 microg/kg, s.c.). One received unpaired presentations (separated by days), one received two unpaired presentations and one paired (i.e., simultaneous) presentation, and one received three paired presentations. Shams received three sucrose presentations paired with saline. Single, but not multiple pairings of B with ingestion of a 32% sucrose solution enhanced later sucrose ingestion, a memorial-like effect that carried over into later, opposite contrast-like effects upon presentation of a less-preferred 4% sucrose solution. These effects could not be easily ascribed to differences in training, other than the pairing regimen itself, nor to motivational differences at the time of testing, and were presumed to be memorial. The pairing and frequency-dependence of these appetitive phenomena are analogous to what is frequently observed during acute or chronic exposure to aversive situations and/or neuromodulatory stress hormones, in terms of their bidirectional effects on memory. Through effects on memory, stress hormones may modulate reward and reward relativity.     

Decreasing driver speeding with feedback and a token economy

On-road research suggests that driver feedback combined with a token economy (a system of delayed reinforcement whereby tokens or points are distributed following a desired behaviour and are later exchanged for desired items) can reduce speeding, and that an incentive system without feedback may be sufficient to achieve this reduction. In two studies, we investigated the necessary and sufficient conditions required for this intervention to reduce speeding, and the efficacy of conducting such research using a driving simulator. Study 1 served to validate the simulator procedure. Participants completed a simulated drive while receiving feedback on their speed and a speed-based token economy. The intervention decreased their speeding compared with that of a control group. Study 2 investigated the amount of speed reduction that could be achieved with just one intervention component (i.e., feedback alone or a token economy alone) compared with feedback and a token economy combined or a control condition. Participants completed a 30-min simulated drive. Overall, drivers who received feedback combined with a token economy spent the least amount of time driving above the speed limit, had the slowest mean speed, and had the smallest standard deviation of speed. Drivers exposed to a token economy alone showed similar speed reductions. However, drivers exposed to feedback alone drove at speeds similar to control participants. Replicating these results under more realistic operating conditions could inform policy-makers and car manufacturers. Furthermore, the simulator proved a cost-effective and efficient means for examining the intervention.