July 26, 2022
Identifying potential determinants of rationality—interpreted as a characteristic of decision makers—is of great relevance from an applied science perspective: both policy makers and industry have a pronounced interest in understanding which individuals make rational decisions, be it to design effective policies, enhance equity, or fine-tune talent selection processes. However, especially for research at the frontier of foundation to application, we must ensure that our measurements are precis eand reliable. Here, we show that established empirical measurements of rationality are not reliable enough, implicating the urgent need for advances in measurement of rationality.
Click also here for a layman summary (in German)
Nitsch FJ, Lüpken LM, Lüschow N, Kalenscher T (2022) On the reliability of individual economic rationality measurements. Proc Natl Acad Sci U S A 119:e2202070119. pdf
March 16, 2022
We are generous toward others, but not toward everyone alike: we are happy to accept costs to help our best friends, but we are much less willing to help random strangers on the street - a phenomenon called social discounting. Generosity not only depends on the perceived social distance to others, but also on our current hormonal state. Here, we asked if generosity toward socially close and socially remote others varies across the female menstrual cycle. We found that this was indeed the case: generosity toward relevant close others, but not toward remote strangers, increased as a function of increased progesterone as well as decreased estradiol levels across the menstrual cycle. High progesterone as well as low estradiol levels are characteristic for the luteal phase during the menstrual cycle. Our results are in line with evolutionary accounts of the role of hormones in social behavior and altruism that predict that women would have increased tendencies to tend-and-befriend during the luteal phase, possibly in preparation for potential pregnancy. In a more general sense, our results support the idea that our behavior, including our social preferences, are, among others, determined by our current hormonal state. This paper was selected as the Editor's Choice of Psychoneuroendocrinology in June 2022.
Sellitto M, Kalenscher T (2022) Variations in progesterone and estradiol across the menstrual cycle predict generosity toward socially close others. Psychoneuroendocrinology 140:105720. pdf
March 2, 2022
Felix Nitsch just successfully defended his PhD on a "Stress Test of Rationality". His PhD was - very deservedly - graded with high distinction. You can download his thesis here.
Congratulations, Dr. Felix!
June 21, 2021
Rats are social animals who, like many other social species, talk with each other about significant events in their environment. They communicate, among others, in the ultrasonic range: they use ultrasonic vocalizations (USVs) to transmit information about the nature and the value of social as well as non-social rewards, cues and threats in their environment. USVs can be broadly categorized into 22 and 50 kHz call categories, which can be further classified into subtypes based on their sonographic features. But are there distinct USV signatures that are unique for social versus non-social events? Recent research suggests that this is indeed the case, but we still know only very little about the social versus non-social significance of USV subtypes. Here, we aimed to gain an overview of the rat vocal response repertoire in social and non-social contexts. Rats repeatedly decided between a non-social (i.e., access to 2%, 5%, and 10% sucrose rewards) and social reward (interaction with another Juvenile rat) while we measured their vocal responses. We found that rats preferred social interaction with the Juvenile when the value of the non-social reward was low (low sucrose concentration), but their preference reversed in favour of sucrose consumption when its value increased (high sucrose concentration). This value-dependent trade-off between social and non-social reward consumption was accompanied by distinct, reward-type-specific USV signatures: in general, rats vocalized more during social interaction than during sucrose consumption. But, while flat calls were preferentially emitted in the non-social context, the Trill and Composite USV subtypes were produced more in conjunction with social interaction. The existence of distinct, reward-domain and -value-dependent USV signatures might suggest that USVs are context-dependent communicative devices aimed at inviting social contact rather than static epiphenomena of domain-general reward values linked to the consumption of both social and non-social rewards.
Seidisarouei D, van Gurp S, Pranic NM, Noguer Calabus I, van Wingerden M, Kalenscher T (2021) Distinct Profiles of 50 kHz Vocalizations Differentiate Between Social Versus Non-social Reward Approach and Consumption. Front Behav Neurosci 15:693698. pdf
June 11, 2021
We like to share food, drinks, time, or money with others. However, we are much more generous with people we feel close to, like good friends or family, than with socially more distant others, such as a person living one block away, or a complete stranger on the street. This decrease in generosity is called social discounting. We have recently shown that a simple nudge drastically changes social discounting: we hypothesized that the way the decision problem was described made a difference in how generous participants were toward strangers. More specifically, we reasoned that framing a generous choice as preventing a loss to others (loss frame) rather than granting them a gain (gain frame) would promote generosity, even towards socially distant others. To test this hypothesis, we designed a social sharing task with a gain and a loss frame. Both frames were economically equivalent; hence, it did not really matter if participants made their choices in the gain or in the loss frame, the financial outcomes for themselves and the others were exactly identical across frames. In four behavioral replications, we found that generosity was less sensitive to social distance in the loss than the gain frame, implying that participants became much more generous toward remote strangers. Using fMRI, we replicated our previous finding of the involvement of temporoparietal junction (TPJ) in social discounting (Strombach et al., 2015). Importantly, we also found that the insular cortex was selectively recruited during generous choices in the loss, but not the gain frame, suggesting that insula might reflect the motives
underlying the generosity boost observed in the loss frame. Our study design allowed us to specify and test a neurally plausible model how generosity would be fostered by the mere description of the decision problem. In our previous study (Strombach et al., 2015), we argued that TPJ would facilitate generous decision-making in the gain domain by modulating basic reward signals in the ventromedial prefrontal cortex (VMPFC), incorporating vicarious reward value into an otherwise exclusive own-reward value representation. Here, we expand on this idea and propose that, in addition to the TPJ-VMPFC connectivity in the gain frame, frame-related information in the loss frame would activate insula, which in turn would down-regulate own-value-representations in VMPFC, thus decreasing the attractiveness of own-rewards and, hence, promoting generosity. To test this idea, we ran dynamic causal modelling and mediation analyses. Our results support our network model of frame-dependent social discounting. They suggest that a differential activation of either the TPJ-VMPFC pathway in the gain frame, or the insula-VMPFC pathway in the loss frame, reflect the distinct decision motives underlying choice behavior in our task. Overall, our results imply that prosocial attitudes towards strangers are malleable and strongly depend on the architecture of the decision problem.
Sellitto M, Neufang S, Schweda A, Weber B, Kalenscher T (2021) Arbitration between insula and temporoparietal junction subserves framing-induced boosts in generosity during social discounting. NeuroImage, 238, 118211. pdf
June 4, 2021
Who doesn’t know this? You are really stressed because of this dangerously close deadline. While working really hard to meet your deadline, you stuff yourself with crisps and other junk food that you would normally not eat, at least not in this amount. This example suggests that stress has an impact on our dietary preferences, that is, we prefer to eat different things when we’re stressed than when we’re not. Stress effects on choice preferences have been reported widely in the literature, not only on dietary preference, but also on risk, time and social preferences. Economic theory typically assumes that our preferences should be stable during the time period of observation, everything else equal. Hence, economic theory has no problem in dealing with preference reversals when external factors change, for example, time of day, age or hunger. The problem with stress is that it is not visible: an observer cannot readily know if you are stressed or not. If an economist were to measure your dietary preferences before you are stressed, and compare them to your preference while you are stressed, it would seem as if your preferences have changed, in apparent violation of the stability assumption in economics. In the present study, we measured dietary preferences in stressed and non-stressed participants in distinct stress-hormonal states, and estimated how consistent they were in their food preferences within (but not across) states. Contrary to our expectations, we found that acute stress had no effect on choice consistency, but an exploratory analysis showed that chronic, long-term stress was associated with compromised consistency. Hence, as often in the stress field, the story is complicated.
Nitsch FJ, Sellitto M, Kalenscher T (2021) The effects of acute and chronic stress on choice consistency. Psychoneuroendocrinology 131:105289. pdf
See also: Nitsch F, Sellitto M, Kalenscher T (2021) Trier social stress test and food-choice: Behavioral, self-report & hormonal data. Data in Brief 37:107245. pdf
May 21, 2021
Do you like beer? Well, if you do, you probably noticed that the beer prices in Germany constantly go up every year. This steady increase in beer prices is really annoying because it means that we can less and less afford to drink beer, right? Well, fortunately, this is not really the case since our income is also increased every year by approximately the same rate as the beer prices go up. So, we can continue drinking our beer! To put this beer story in more formal terms: if the price level of goods and services increases, our demand for more expensive commodities decreases. However, our income is usually adjusted by the rate of inflation to compensate for these price changes so that we can continue our original consumption pattern. We have recently shown that, surprisingly, rats are not much different than humans when it comes to inflation adjustment! Rats change their consumption of costly chocolate or vanilla rewards when their prices change, i.e., when the effort required to obtain a reward is increased or decreased. Notably, when we compensated for these price changes by adjusting the rats’ income (the budget of effortful operants available in a session to purchase those rewards), demand elasticity, i.e., the change in demand in response to price changes, was different than when the budget was not adjusted. Hence, exactly like humans, rat consumers seem to consider their income in their cost-benefit calculations. In the new study, we replicated our budget effect in rat consumers. Importantly, we showed that rats with lesions in their anterior cingulate cortex (ACC), a brain area known for processing effort costs in decision-making, abolished the budget effects: rats without ACC still reduced their demand of rewards when rewards became more expensive, much like normal rats, and they increased their demand when rewards became cheaper. However, unlike normal rats, ACC-lesioned animals did not consider their budget in their choices anymore; they changed their demand in response to the price changes independent of whether the budget was compensated or not. This result suggests that ACC is important for computing purchasing power – a core variable in economic choice theory.
Hu Y, van Wingerden M, Sellitto M, Schäble S, Kalenscher T (2021) Anterior Cingulate Cortex Lesions Abolish Budget Effects on Effort-Based Decision-Making in Rat Consumers. J Neurosci 41:4448-4460. pdf
March 22, 2021
We are not very good in pursuing our future goals (just think about how much Netflix you watched in the last few months, and how much potatoe chips you ate instead of behaving more consistent with your actual health and fitness goals...). This is not much different in neurological and neuropsychological patients who often have to engage in lengthy, effortful and boring self-directed rehabilitative training, yet often struggle to meet this motivational challenge. The problem is aggravated by the fact that there are often better things to do than engaging in rehabilitative activities, distracting from the patients' training goals. Hence, willpower failures, although common and familiar to all of us, can be highly problematic if they compromise adherence to rehabilitative training, and, thus, recovery after brain damage. In the new study, we asked if a decision-neuroscientific add-on intervention, inspired from behavioral and neuroconomics, helps severely impaired stroke patients to resolve their self-control problem in favor of improved adherence to rehabilitation. Specifically, we show that precommitment - a cognitive strategy by which access to anticipated temptations are deliberately removed ahead of time - motivates patients to persist with effortful cognitive training in order to stay on track with their goals to recover after stroke. In the precommitment condition, patients could choose to restrict tempting options that competed with self-directed training, specifically the possibility to meet visitors. Compared to control patients who could not precommit to restrict visitor time, this intervention tripled the training dose that patients spent with a cognitive rehabilitation device. By consequence, patients who used precommitment showed much greater improvement in skills than control patients. Hence, precommitment is highly effective in improving the adherence to effortful cognitive training in severely impaired stroke patients.
Studer B., Timm A., Sahakian B., Kalenscher T., Knecht S (2021). A decision-neuroscientific intervention to improve cognitive recovery after stroke. Brain. Get the pdf here
October 6, 2020
We usually find it important that others are treated fairly. However, while some people are very sensitive to unfairness, others couldn’t care less. It has been suggested that the strength of fairness preferences is related to the action of the neurotransmitter serotonin, among many other things. But how and where does serotonin act to increase our sensitivity to fairness? We have recently shown that rats prefer mutual-rewards over own rewards, that is, rats prefer choice alternatives where food rewards are delivered to them and to conspecifics over alternatives where only them, but not their conspecifics receive food. We could furthermore show that these mutual-reward preferences depend on the integrity of the amygdala: if the amygdala is damaged, rats do not care about reward to others anymore. In our new study, we asked if the preference for mutual-rewards is related to serotonin action in the amygdala. To find out, we injected serotonin agonists locally into the amygdala. We found that rats treated with these serotonin agonists were indeed more prosocial towards their conspecifics than rats treated with physiologically inactive vehicle solution. We believe that serotonin action in the amygdala promotes prosociality by enhancing the rats’ sensitivity to social signals emitted by their conspecifics, thus structuring their social interaction.
Schönfeld LM, Schäble S, Zech MP, Kalenscher T (2020) 5-HT1A receptor agonism in the basolateral amygdala increases mutual-reward choices in rats. Sci Rep 10:16622. pdf
October 5, 2020
Imagine you are doing some home improvements together with your best friend. Both of you are just about to hammer a nail into your new book shelf when your friend screams in agony: she just hit her thumb with the hammer. What would you do? Probably, this scene would instantly catch your attention; you would immediately turn to your friend and you would likely feel her pain and start comforting her. This example not only illustrates that we are able to vicariously experience someone else’s pain, but also that such events are highly attention-grabbing. A popular hypothesis to explain our ability for sharing the affective state of others (you feel your friend's pain) states that the same neural pathways that are activated during our own emotional experiences are also recruited when observing somebody else living through something similar. Such affective mirror neuron activity has recently been identified in the anterior cingulate cortex (ACC) of rodents (Carrillo et al., 2019). However, a paper recently published in Current Biology offers a different view: Kevin Schneider, Matt Roesch and colleagues argued that ACC was important for driving the attention towards salient events in the social environment, such as reward and pain to others, rather than being part of an emotional mirror system (Schneider et al., 2020). So, what is ACC doing, social attention or emotional mirroring? In the new commentary, I discuss the evidence for and against both ideas. Although there is convincing evidence supporting both hypotheses, there are insufficient grounds to clearly reject either one. Stay tuned!
Kalenscher T (2020) Social Neuroscience: How the Brain Attends to the Joys and Pains of Others. Curr Biol 30:R1076-R1078. pdf
October 2, 2020
We often consider the well-being of others: we rejoice with the happiness of our friends when good things happen to them, and we feel their pain when bad things are happening. But do animals also vicariously experience the joy of conspecifics? In our new study, we show that they do! We made use of a phenomenon well-known in the reinforcement learning literature called “blocking and unblocking”. If an animal has thoroughly learned the association between a conditioned stimulus and a reward, and then a second conditioned stimulus is added to the first one, the associative strength between the second, novel conditioned stimulus and the reward will be zero; that is, if this novel stimulus is presented alone, the animal will not show any conditioned response. In other words, the formation of the stimulus-reward association is blocked. However, this blocking can be unblocked by increasing the reward size once the second, novel stimulus is added to the stimulus set. We used the unblocking paradigm to test if rats positively value rewards to conspecifics. We reasoned that, if rats really attached vicarious value to rewards delivered to others, then reward to others should also result in unblocking, even if own-rewards were not increased. By contrast, if rats did not consider reward delivered to conspecifics, then there should be no unblocking. We found evidence for the former: when actor rats had fully learned a stimulus-self-reward association, adding a cue that predicted additional reward to a partner, but not to self, unblocked associative learning about this cue. This finding shows that rats consider reward to others during social learning.
Congratulations, Sander!! Really cool, Marijn!!
van Gurp S, Hoog J, Kalenscher T, van Wingerden M Vicarious reward unblocks associative learning about novel cues in male rats. eLife 9:e60755. pdf
September 14, 2020
Be honest: how much money did you give to this beggar who approached you last weekend? Maybe you gave them a few Euros, maybe you did not give them anything. But would it be acceptable to take away money from them if you needed it? Problably not! This example shows that most people find it not okay, but somewhat morally acceptable to not share your wealth with socially remote others, but the same people find it utterly inaccaptable to take away money from someone else. We made use of this observation and designed a task in which participants either chose to share an endowment with others (the so-called give frame), or to take away money parts of the endowment of another person (the take frame). Importantly, the game was constructed in such a way that both frames were economically exactly equivalent; hence, it did not really matter if participants made their choices in the take or in the give frame, the financial outcomes for themselves and the others were exactly identical across frames (for an in-depth analysis of this task, see here). Participants played this game with socially close others, for example, good friends, but also with socially more remote others, for example, their neighbour who they are acquainted with, but not friends, or with socially very distant others, such as a person on the street who they have never met before. We found that participants shared a lot more money with others, especially socially remote others, in the take frame compared to the give frame, even though both frames were economically identical. In the new study, we asked if acute stress eroded this framing effect on generosity. Stress is known to change social behavior. Among others, it erodes compliance to social norms, such as "do not hurt others", or "respect others' property rights". We therefore thought that acute stress might compromise the frame-induced increase in generosity in the take frame. And this is indeed what we found: stressed participants were much less generous in the take frame compared to non-stressed control participants, even though there was no difference in generosity in the give frame.
Schweda A, Margittai Z, Kalenscher T (2020) Acute stress counteracts framing-induced generosity boosts in social discounting in young healthy men. Psychoneuroendocrinology 121. pdf
December 12, 2019
Stress changes how we socially interact with others. Decades of work on the effects of stress on social behavior has identified two distinct behavioral patterns in stressed individuals: fight-or-flight, i.e., the tendency to aggress or flee in order to protect oneself from potential threats, and the opposite behavior, tend-and-befriend, i.e., the tendency to affiliate with others in order to mobilize social resources in times of peril. However, no unifying framework exists that predicts under which circumstances one or the other response occurs. Here, we hypothesized that stress stimulates both tendencies, but that fight-or-flight is primarily directed against a potentially hostile outgroup, while tend-and-befriend is mainly shown towards a supportive ingroup. We further hypothesized that both tendencies are regulated by distinct, discernable neurohormonal mechanisms. We tested this hypothesis by letting stressed or non-stressed participants play a well-established intergroup social dilemma game in which individual resource allocations could reveal prosocial and hostile motives towards in- or outgroup members. Although our experiment was well powered, we find no direct effect of stress on prosocial and hostile decisions, but explorative analyses suggest that heart-rate, saliva testosterone, and saliva cortisol could predict allocation patterns. We conclude that further research is needed, especially to elucidate which task structure is needed to capture the underlying mechanisms of the impact of stress on social behavior.
Schweda A, Faber NS, Crockett MJ, Kalenscher T (2019) The effects of psychosocial stress on intergroup resource allocation. Sci Rep 9:18620. pdf
November 12, 2019
Rats communicate with each other by using calls in the ultrasonic range, so-called ultrasonic vocalizations (USVs), which can be divided into two categories: USVs in the 50-kHz range provide information about a positive state, whereas USVs in the 22-kHz range signal a negative state or even a threat. Hearing USVs might be rewarding for rats, possibly due to their social-communicative function, and induces various behaviors in recipient rats. In this experiment, our postdoc Dr. Lisa Schönfeld and our PhD student Maurice Zech tested the importance of the basolateral amygdala (BLA) in motivating behavioral responses towards USVs. In an eight-arm radial maze, control rats robustly approached a speaker that emitted 50-kHz USVs located at the end of one arm, but spent more time in the middle of the maze when 22-kHz USVs were played from that speaker. Bilateral lesions of the BLA reduced approach behavior and increased the time spent on the central platform in the middle of the maze. These differences between rats with and without BLA lesions were only evident during phases of USV playback, but not during preceding phases, where rats could freely explore the radial maze without any USVs being played. Also general locomotion and hearing abilities of rats with BLA lesions did not differ from control rats, thus BLA lesions seemed to specifically affect behavior to stimuli with a social significance. Our results provide new information about the neurobiological basis of social communication, and eventually social behavior, in rats. Congratulations, Lisa and Maurice!
Schönfeld LM, Zech MP, Schable S, Wohr M, Kalenscher T (2019) Lesions of the rat basolateral amygdala reduce the behavioral response to ultrasonic vocalizations. Behav Brain Res:112274.pdf
October 31, 2019
In this paper, we investigated generosity among the Maasai in Kenya. We studied how generous behavior changes across social distance between the donor and the recipient of help, that is, how socially close or socially distance a participant felt to the recipient of help (a phenomenon called social discounting). We were particularly interested in how social discounting differs between different sharing commodities, such as money, water, milk, cows, access to grassland and so on. We find that the Maasai showed very similar social discounting to Western or Chinese participants. However, importantly, the steepness by which generosity decayed across social distance was highly dependent on the shared commodity. Our results imply that relatively more valued goods are shared less readily than less valued goods, even if relative valuation is purely subjective and culture-specific. In addition, it is likely that sharing behavior of the different goods is also modulated by social and cultural expectations. We discuss these aspects from an economic, psychological and anthrophological perspective. Together with and .
Archambault C, Kalenscher T, Laat J (2019) Generosity and livelihoods: Dictator game evidence on the multidimensional nature of sharing among the kenyan maasai. Journal of Behavioral Decision Making:1-12. pdf
June 21, 2019
In this review paper, our PhD student Lina Oberließen reviews the literature on inequity aversion - the aversion against unequal reward distributions between conspecifics - in non-human animals. Despite growing evidence supporting the existance of inequity aversion in animals, there is still an ongoing debate whether inequity aversion represents a truly social phenomenon or whether it is driven by non-social aspects of the task. Lina provides a comprehensive and scholarly discussion of the evidence for or against the existance of inequity aversion in animals, and she examines mechanistic and evolutionary theories of inequity aversion. Congratulations, Lina!
Oberließen L, Kalenscher T (2019) Social and Non-social Mechanisms of Inequity Aversion in Non-human Animals. Front Behav Neurosci 13:1-11. pdf
January 7, 2019
Right on time for your new year's resolution! Did you plan to exercise more and live a more healthy lifestyle in 2019? And did you (once again, same procedure as every year, right?) quickly realize that you struggle to meet your exercise goals because procrastination, laziness or other temptations tend to get in the way of achieving them? If you do, this new paper might be interesting for you. We show that precommitment - a cognitive strategy by which access to anticipated temptations are deliberately removed ahead of time - helps to motivate us to persist with effortful actions in order to stay on track to achieve our long-term goals. Published in cooperation with Bettina Studer and Stefan Knecht from St. Mauritius Therapieklinik in Meerbusch and the Institute of Clinical Neuroscience and Medical Psychology, Heinrich-Heine-University Dusseldorf
Studer B, Koch C, Knecht S, Kalenscher T (2019) Conquering the inner couch potato: precommitment is an effective strategy to enhance motivation for effortful actions. Philos Trans R Soc Lond B Biol Sci 374:20180131. pdf
December 20, 2018
When making decisions under risk, we often attach more weight to prospective losses than to equivalent gains. This is one of the most prominent and deleterious decision biases called loss aversion. By consequence of loss aversion, we might chase our losses, and thus accumulate more of them, or we may ask more money for selling goods than we would be willing to spend to buy equivalent goods. In this new study, we show that the two stress neuromodulators Cortisol and Noradrenaline combined, but not in isolation, reduce loss aversion. Our results have implications for understanding hormonal factors influencing the susceptibility to decision biases.
Margittai Z, Nave G, Van Wingerden M, Schnitzler A, Schwabe L, Kalenscher T (2018) Combined Effects of Glucocorticoid and Noradrenergic Activity on Loss Aversion. Neuropsychopharmacology 43:334-341. pdf
December 5, 2018
People often cope with stress by investing into social relationships. We have recently shown that psychosocial stress alters the social discount function; that is, in times of stress, individuals offer costly help to a delimited group of close friends and family, but not to socially more remote others. In this new paper, we demonstrate that the stress-hormone cortisol has a very similar effect on social discounting compared to psychosocial stress: exogenous hydrocortisone administration boosts generosity towards socially close, but not socially remote others. Interestingly, this cortisol-related upregulation of prosocial behavior was offset by concomittant administration of yohimbine, a drug that amplifies noradrenergic action. These findings have implications for understanding why stressed individuals sometimes respond with a tend-and-befriend response, while, at other times, they show fight-or-flight tendencies: there is a time-dependent neuroendocrine response to stress with combined cortisol and noradrenergic action right after stress, and cortisol action alone in the aftermath of stress. Our data suggest that prosociality is upregulated in the aftermath of stress when coping mechanisms act to reverse the acute stress effects and, thus, normalize the stress response, but prosocial tendencies are actually downregulated right after stress when fight-or-flight tendencies dominate. Congratulations, Zsofia!
Margittai Z, Van Wingerden M, Schnitzler A, Joels M, Kalenscher T (2018) Dissociable roles of glucocorticoid and noradrenergic activation on social discounting. Psychoneuroendocrinology 90:22-28. pdf
November 21, 2017
Our decisions are often very short-sighted; we are consequently not very good in making choices that are in line with our long-term interests. Why did evolution favor a choice mechanism that leads to overweighting of short-term outcomes at the expense of our long-term plans? In this new paper, we argue that it is true that we fail to maximize economic utility when making choices between future rewards, but that the very same choice mechanism that is considered suboptimal from an economics perspective is actually optimal when looking through the lens of optimal foraging: hyperbolic discounting - the steep and asymmetric devaluation of future rewards that leads to short-sighted decision-making - is a prerequisite for maximizing another currency than econoomic utility: long-term reward rate - the amount of reward gained per time unit. Thus, short-sightedness might not be so suboptimal, after all.
Seinstra M, Sellitto M, Kalenscher T (2017) Rate maximization and hyperbolic discounting in human experiential intertemporal decision making. Behavioral Ecology:1-11. pdf
May 2, 2017
This commentary article, just published in Nature Human Behaviour, accompanies a paper by Kruti Vekaria, Abigail Marsh and others showing that altruistic kidney donors value the welfare of socially distant others higher than normal control participants.
Kalenscher T (2017) Social psychology: love thy stranger as thyself. Nature Human Behaviour 04:Article no. 0108. pdf