Hungry pigeons prefer sooner rare food over later likely food or faster information.

Introduction: Making decisions and investing effort to obtain rewards may depend on various factors, such as the delay to reward, the probability of its occurrence, and the information that can be collected about it. As predicted by various theories, pigeons and other animals indeed mind these factors when deciding. Methods: We now implemented a task in which pigeons were allowed to choose among three options and to peck at the chosen key to improve the conditions of reward delivery. Pecking more at a first color reduced the 12-s delay before food was delivered with a 33.3% chance, pecking more at a second color increased the initial 33.3% chance of food delivery but did not reduce the 12-s delay, and pecking more at a third color reduced the delay before information was provided whether the trial will be rewarded with a 33.3% chance after 12 s. Results: Pigeons' preference (delay vs. probability, delay vs. information, and probability vs. information), as well as their pecking effort for the chosen option, were analyzed. Our results indicate that hungry pigeons preferred to peck for delay reduction but did not work more for that option than for probability increase, which was the most profitable alternative and did not induce more pecking effort. In this task, information was the least preferred and induced the lowest level of effort. Refed pigeons showed no preference for any option but did not drastically reduce the average amounts of effort invested. Discussion: These results are discussed in the context of species-specific ecological conditions that could constrain current foraging theories.

Model-based estimates for operant selection.

We present a new methodology to partition different sources of behavior change within a selectionist framework based on the Price equation-the multilevel model of behavioral selection. The multilevel model of behavioral selection provides a theoretical background to describe behavior change in terms of operant selection. Operant selection is formally captured by the covariance-based law of effect and accounts for all changes in individual behavior that involve a covariance between behavior and predictors of evolutionary fitness (e.g., food). In this article, we show how the covariance-based law of effect may be applied to different components of operant behavior (e.g., allocation, speed, and accuracy of responding), thereby providing quantitative estimates for various selection effects affecting behavior change using data from a published learning experiment with pigeons.

Differences in paradoxical choice between pigeons (Columba livia) and rats (Rattus norvegicus): The problem of cue trackability.

Organisms are believed to attempt to maximize their net energy intake while foraging. The paradoxical choice task shows that they may instead prefer to obtain information rather than primary reward when the outcome is uncertain. That is, they prefer stimuli that consistently predict food or no food (informative option), to stimuli that inconsistently predict both food and no food in larger amounts (noninformative option). This task also seems to indicate that some species (like pigeons, Columba livia, and starlings, Sturnus vulgaris) are more prone to choose the informative option, while other species (like rats, Rattus norvegicus, and humans, Homo sapiens) tend to favor reward procurement through the noninformative option. There is empirical evidence for and against this view. However, an analysis of the literature suggests that species differences in paradoxical choice might be less pronounced than often believed. We argue that pigeons and rats are usually not tested under conditions that are motivationally equivalent for both species-in particular, the opportunities to track consistent stimulus-food pairings are less often met in the rat studies than in the pigeon studies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Reactivity to pseudorandom environmental patterns in woodlice: Effects of hydric deprivation and light exposure.

Exploratory activity is an essential component of animal behavior, including among invertebrate species. This study examined the effects of hydric deprivation and their possible modulation by light exposure on locomotion and rearing-up behavior in two woodlice species, Porcellio scaber (Latreille 1804) and Armadillidium vulgare (Latreille 1804). It was also an attempt to replicate previous findings on the stimulation of these behaviors in P. scaber, exposed to (pseudo)random vs. regular visual and tactile patterns in a small enclosure. In Experiment 1, two groups of P. scaber and two groups of A. vulgare were exposed to randomly vs. regularly distributed visual (black and white) and tactile (grained and smooth) patterns for approximately 20 min. No rewards were present in the environment and the woodlice were tested without preliminary hydric deprivation. In Experiment 2, the same procedure was used but the woodlice were tested following a 20-min hydric deprivation under a bottle cap (darkness). Experiment 3 replicated this procedure with the 20-min hydric deprivation spent in a plastic cup (light exposure). The results of Experiments 1 and 3 provide partial replication with A. vulgare, but not P. scaber, of the previous findings: Random patterns stimulate rearing-up behavior on the apparatus' vertical walls more than regular patterns. Also, a more aversive stimulation in Experiment 3 compared to Experiment 2, increased locomotion, especially in the random environment. The role of hydric deprivation and light exposure in the process of escaping from a hostile environment is discussed, as well as the effects of the treatments used in these experiments.

Using a behavior random permutation model to identify displacement grooming in ungulates.

Behavior affects an individual's life in all aspects, e.g., enhancing fitness, leveraging predation risk, and reducing competition with conspecifics. However, the sequential distribution of behaviors received less attention and is unclear what the function of displacement behavior is. Displacement activities can be found in vertebrate species but there is no formal method to determine whether a behavior is expressed as a displaced or normal activity. Analyzing the sequential distributions of behaviors in a natural setting may allow researchers to identify unexpected distributions as a possible signature of displacement activities. In this study, we used a behavior random permutation model to detect the presence of a displacement activity in the Tibetan antelope Pantholops hodgsonii and the Tibetan gazelle Procapra picticaudata. The results showed that grooming in both ungulates tended to be accompanied with vigilance, and the frequency of grooming after vigilance was significantly higher than before vigilance. A significant positive correlation between the scan rate and grooming rate in the 2 ungulates was obtained. We suggest that grooming could sometimes be expressed as a displacement activity in ungulates. In addition to providing a general method for further research on displacement activities in a variety of animal species, this study sheds light on the importance of a spectral analysis of sequential distribution of animal behaviors. Behavior random permutation models can be used to explore the relevance between any 2 behaviors in a specific sequence, especially to identify a myriad of unexpected behaviors relative to their normal context of occurrence.

Overmatching under food uncertainty in foraging pigeons.

One major survival-related activity of organisms is to seek food in their environment. To this end, they exploit previously rewarding locations and attempt to approach the cues predictive of the edible items they detect or expect. But foraging is unlikely to be a matter of reinforcement only. If it was, however, foraging activity should follow principles of extinction learning: It should be abolished in a location without reinforcement and proportionally be reduced in a partially reinforced location relative to a fully reinforced one containing the same number of food items. We tested these two hypotheses using a foraging board, which allowed pigeons to find food items hidden in perforated holes. Our results showed that the overall time spent and the overall number of pecks given in one area was related to reinforcement density in that area. To a lesser extent, the same phenomenon occurred with respect to the number of visits per area. However, the time-per-visit and pecks-per-visit ratios were higher in the partially vs. fully reinforced area, suggesting that the pigeons foraged more than expected when food was uncertain. These results will be discussed in the context of the matching law and optimal foraging.

Quantifying the instrumental and noninstrumental underpinnings of Pavlovian responding with the Price equation.

The Price equation is a mathematical expression of selectionist and non-selectionist pressures on biological, cultural, and behavioral change. We use it here to specify instrumental and noninstrumental behaviors as they arise within the context of the Pavlovian autoshaping procedure, for rats trained under reward certainty and reward uncertainty. The point of departure for this endeavor is that some portion of autoshaped behavior referred to as goal-tracking appears instrumental-a function of resource attainment (the individual approaches the location where the unconditioned stimulus is to be delivered). By contrast, some other portion of autoshaped behavior referred to as sign-tracking is noninstrumental-irrelevant to making contact with the to-be-delivered unconditioned stimulus. A Price equation model is proposed that unifies our understanding of Pavlovian autoshaping behavior by isolating operant and respondent influences on goal-tracking (instrumental) and sign-tracking (noninstrumental) behavior.

Effort-motivated behavior resolves paradoxes in appetitive conditioning.

Motivated behavior has long been studied by psychologists, ethologists, and neuroscientists. To date, many scientists agree with the view that cue and reward attraction is the product of a dopamine-dependent unconscious process called incentive salience or "wanting". This process allows the influence of multiple factors such as hunger and odors on motivational attraction. In some cases, however, the resulting motivated behavior differs from what the incentive salience hypothesis would predict. I argue that seeking behavior under reward uncertainty illustrates this situation: Organisms do not just "want" (appetite-based attraction) cues that are inconsistent or associated with reward occasionally, they "hope" that those cues will consistently predict reward procurement in the ongoing trial. Said otherwise, they become motivated to invest time and energy to find consistent cue-reward associations despite no guarantee of success (effort-based attraction). A multi-test comparison of performance between individuals trained under uncertainty and certainty reveals behavioral paradoxes suggesting that the concept of incentive salience cannot fully account for responding to inconsistent cues. A mathematical model explains how appetite-based and effort-based attractions might combine their effects.

Mirror Self-Recognition in Pigeons: Beyond the Pass-or-Fail Criterion.

Spontaneous mirror self-recognition is achieved by only a limited number of species, suggesting a sharp "cognitive Rubicon" that only few can pass. But is the demarcation line that sharp? In studies on monkeys, who do not recognize themselves in a mirror, animals can make a difference between their mirror image and an unknown conspecific. This evidence speaks for a gradualist view of mirror self-recognition. We hypothesize that such a gradual process possibly consists of at least two independent aptitudes, the ability to detect synchronicity between self- and foreign movement and the cognitive understanding that the mirror reflection is oneself. Pigeons are known to achieve the first but fail at the second aptitude. We therefore expected them to treat their mirror image differently from an unknown pigeon, without being able to understand that the mirror reflects their own image. We tested pigeons in a task where they either approached a mirror or a Plexiglas barrier to feed. Behind the Plexiglas an unknown pigeon walked at the same time toward the food bowl. Thus, we pitched a condition with a mirror-self and a foreign bird against each other, with both of them walking close toward the food bowl. By a detailed analysis of a whole suit of behavioral details, our results make it likely that the foreign pigeon was treated as a competitor while the mirror image caused hesitation as if being an uncanny conspecific. Our results are akin to those with monkeys and show that pigeons do not equal their mirror reflection with a conspecific, although being unable to recognize themselves in the mirror.

Effects of partial reinforcement on autoshaping in inbred Roman high- and low-avoidance rats.

Individuals trained under partial reinforcement (PR) typically show a greater resistance to extinction than individuals exposed to continuous reinforcement (CR). This phenomenon is referred to as the PR extinction effect (PREE) and is interpreted as a consequence of uncertainty-induced frustration counterconditioning. In this study, we assessed the effects of PR and CR in acquisition and extinction in two strains of rats, the inbred Roman high- and low-avoidance (RHA and RLA, respectively) rats. These two strains mainly differ in the expression of anxiety, the RLA rats showing more anxiety-related behaviors (hence, more sensitive to frustration) than the RHA rats. At a neurobiological level, mild stress is known to elevate corticosterone in RLA rats and dopamine in RHA rats. We tested four groups of rats (RHA/CR, RHA/PR, RLA/CR, and RLA/PR) in two successive acquisition-extinction phases to try to consolidate the behavioral effects. Animals received training in a Pavlovian autoshaping procedure with retractable levers as the conditioned stimulus, food pellets as the unconditioned stimulus, and lever presses as the conditioned response. In Phase 1, we observed a PREE in lever pressing in both strains, but this effect was larger and longer lasting in RHA/PR than in RLA/PR rats. In Phase 2, reacquisition was fast and the PREE persisted in both strains, although the two PR groups no longer differed in lever pressing. The results are discussed in terms of frustration theory and of uncertainty-induced sensitization of dopaminergic neurons.

From sign-tracking to attentional bias: Implications for gambling and substance use disorders.

Sign-tracking behavior in Pavlovian autoshaping is known to be a relevant index of the incentive salience attributed to reward-related cues. Evidence has accumulated to suggest that animals that exhibit a sign-tracker phenotype are especially vulnerable to addiction and relapse due to their proneness to attribute incentive salience to drug cues, and their relatively weak cognitive and attentional control over their behavior. Interestingly, sign-tracking is also influenced by reward uncertainty in a way that may promote gambling disorder. Research indicates that reward uncertainty sensitizes sign-tracking responses and favors the development of a sign-tracker phenotype, compatible with the conditioned attractiveness of lights and sounds in casinos for problem gamblers. The study of attentional biases in humans (an effect akin to sign-tracking in animals) leads to similar observations, notably that the propensity to develop attraction for conditioned stimuli (CSs) is predictive of addictive behavior. Here we review the literature on drug addiction and gambling disorder, highlighting the similarities between studies of sign-tracking and attentional biases.

Evidence for motivational enhancement of sign-tracking behavior under reward uncertainty.

Reward uncertainty has been shown to invigorate rather than attenuate cue attraction and responding. For example, a number of findings have shown that partial reinforcement in autoshaping increases response rates to a conditioned stimulus (conditional stimulus) in comparison with continuous reinforcement. However, identifying the nature of this effect remains a topical question. The frustration theory posits that animals are frustrated by reward loss and predicts that enhanced responding results from higher response rates to conditional stimulus presentations that follow nonrewarded trials rather than rewarded trials. In contrast, the incentive hope hypothesis suggests that animals are motivated by possible future rewards and predicts similar response rates after rewarded and nonrewarded trials. Our results, which consist of a reanalysis of previously published data (Hellberg, Levit, & Robinson, 2018), are consistent with the incentive hope hypothesis because no differences were found between trials that follow rewarded or nonrewarded trials, or between trials that follow small or larger amounts of food reward in rats. There was also no evidence for an accumulation of frustration across each training session, with rats instead displaying enhanced yet stable responding from beginning to end. The incentive hope hypothesis is also briefly discussed in relation to the concept of incentive salience. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Incentive hope: A default psychological response to multiple forms of uncertainty.

Our target article proposes that a new concept - incentive hope - is necessary in the behavioral sciences to explain animal foraging under harsh environmental conditions. Incentive hope refers to a specific motivational mechanism in the brain - considered only in mammals and birds. But it can also be understood at a functional level, as an adaptive behavioral strategy that contributes to improve survival. Thus, this concept is an attempt to bridge across different research fields such as behavioral psychology, reward neuroscience, and behavioral ecology. Many commentaries suggest that incentive hope even could help understand phenomena beyond these research fields, including food wasting and food sharing, mental energy conservation, diverse psychopathologies, irrational decisions in invertebrates, and some aspects of evolution by means of sexual selection. We are favorable to such extensions because incentive hope denotes an unconscious process capable of working against many forms of adversity; organisms do not need to hope as a subjective feeling, but to behave as if they had this feeling. In our response, we carefully discuss each suggestion and criticism and reiterate the importance of having a theory accounting for motivation under reward uncertainty.

Horizontal and vertical exploration in woodlice: A dual-process model.

Woodlice placed in an unknown experimental enclosure typically run (horizontal exploration) and rear up on the enclosure's walls (vertical exploration). Previous findings with Porcellio scaber indicate that these two behaviors have an opposite temporal distribution and show differential sensitivity to rotation-induced physiological stress. It is argued that the dual-process theory of habituation and sensitization can serve as a basis to account for horizontal and vertical exploratory activities in woodlice. A model is presented. This model could help identify individual variability in "temperament" and to isolate its effects in various behavioral tasks in woodlice and perhaps other invertebrate species.

Pigeons consistently prefer easy over harder access to food: No reversal after direct dopaminergic stimulation.

Many studies show that animals may prefer earned over free food-a phenomenon referred to as "contrafreeloading." In rodents, dopamine-which is involved in incentive motivation and effort-facilitates the occurrence of such a preference. Here, we investigated the behavioral effects of pramipexole (PPX), a dopamine D2/3 receptor agonist, on contrafreeloading in pigeons. In Experiment 1, 2 groups of pigeons (PPX and SAL) were simultaneously exposed to a bowl that contained grains only (easy food option) and a bowl that contained grains covered with sawdust (harder food option) for 6 sessions. They were tested in two treatment conditions (high vs. low amount of food available). In Experiment 2, the two groups of pigeons were first repeatedly presented with the harder food option (training phase, 6 sessions) and then with the two options at the same time (test phase, 3 sessions). In order to potentially increase the physiological effects of PPX, the dose was tripled, and there was a 2-week incubation of the drug between Sessions 3 and 4 at training. The results indicate that the pigeons from both groups preferred to forage on the easy food option, and PPX did not alter this preference. Despite indications that PPX was effective, its action consisted of reducing-rather than magnifying-the attractiveness of the harder food option. It is suggested that pigeons are less motivated to deploy foraging effort than rodents in similar tasks. (PsycINFO Database Record

How foraging works: Uncertainty magnifies food-seeking motivation.

Food uncertainty has the effect of invigorating food-related responses. Psychologists have noted that mammals and birds respond more to a conditioned stimulus that unreliably predicts food delivery, and ecologists have shown that animals (especially small passerines) consume and/or hoard more food and can get fatter when access to that resource is unpredictable. Are these phenomena related? We think they are. Psychologists have proposed several mechanistic interpretations, while ecologists have suggested a functional interpretation: The effect of unpredictability on fat reserves and hoarding behavior is an evolutionary strategy acting against the risk of starvation when food is in short supply. Both perspectives are complementary, and we argue that the psychology of incentive motivational processes can shed some light on the causal mechanisms leading animals to seek and consume more food under uncertainty in the wild. Our theoretical approach is in agreement with neuroscientific data relating to the role of dopamine, a neurotransmitter strongly involved in incentive motivation, and its plausibility has received some explanatory and predictive value with respect to Pavlovian phenomena. Overall, we argue that the occasional and unavoidable absence of food rewards has motivational effects (called incentive hope) that facilitate foraging effort. We show that this hypothesis is computationally tenable, leading foragers in an unpredictable environment to consume more food items and to have higher long-term energy storage than foragers in a predictable environment.

Rotational stress influences sensitized, but not habituated, exploratory behaviors in the woodlouse, Porcellio scaber.

Terrestrial isopods (or woodlice), like the members of the other arthropod taxa, have a sophisticated nervous system that makes them sensitive to specific environmental factors. They can search for survival-related opportunities (e.g., approaching food sources or avoiding sunny areas). Two experiments examined how rotational stress could influence the propensity of common woodlice, Porcellio scaber to exhibit survival-related behaviors such as traveling and rearing up in a hostile environment. Experiment 1 assessed the behaviors of stressed and nonstressed woodlice exposed to a familiar or a novel environment without rewards. Experiment 2 assessed the effects of stress in woodlice given a free choice between a familiar and a novel environment without rewards. In the nonstressed individuals, the results showed a decrease in locomotor activity (habituation) and an increase in the time spent rearing up (sensitization) on the arena's walls over time. In the stressed individuals, repeated rotation had a detrimental effect on the time spent rearing up, but locomotion was decreased only in the stressed individuals that were not preexposed to the test environment beforehand. In addition, immobilization periods-as a plausible indicator of stress-were longer in the absence of preexposure. It is suggested that preexposure had some antistress protective effects on habituated but not on sensitized, exploratory behaviors in woodlice.

Uncertainty processing in bees exposed to free choices: Lessons from vertebrates.

Bees tend to avoid or to show indifference to uncertain ("risky") relative to certain ("safe") food rewards, whether in nectar volume or in nectar concentration. The unattractiveness of uncertain food rewards is also sometimes independent of the energy budget of bees. This pattern of responses seems to differ from that observed in mammals and birds, which may exhibit a strong preference for the uncertainty over the certainty of food delivery on a given trial in dual-choice tasks. Upon analysis of the conditions that determine preference and aversion for uncertain food rewards in "higher" vertebrates, I attempt to demonstrate that bees react to uncertainty in a similar way. It is argued that, because of their social organization and of the type of resources they seek, bees are essentially exposed to situations in which "higher" vertebrates find reward uncertainty unattractive as well. The nature of their representation of food distribution is discussed, and it is suggested that scout bees may differ from recruits with respect to uncertainty processing.