Biomedical subjects

Melissa Bateson

Publications and source records attributed to Melissa Bateson.

7 recordsLinked to original sources

PubMed2025

A large-scale study across the avian clade identifies ecological drivers of neophobia.

Neophobia, or aversion to novelty, is important for adaptability and survival as it influences the ways in which animals navigate risk and interact with their environments. Across individuals, species and other taxonomic levels, neophobia is known to vary considerably, but our understanding of the wider ecological drivers of neophobia is hampered by a lack of comparative multispecies studies using standardized methods. Here, we utilized the ManyBirds Project, a Big Team Science large-scale collaborative open science framework, to pool efforts and resources of 129 collaborators at 77 institutions from 24 countries worldwide across six continents. We examined both difference scores (between novel object test and control conditions) and raw data of latency to touch familiar food in the presence (test) and absence (control) of a novel object among 1,439 subjects from 136 bird species across 25 taxonomic orders incorporating lab, field, and zoo sites. We first demonstrated that consistent differences in neophobia existed among individuals, among species, and among other taxonomic levels in our dataset, rejecting the null hypothesis that neophobia is highly plastic at all taxonomic levels with no evidence for evolutionary divergence. We then tested for effects of ecological factors on neophobia, including diet, sociality, habitat, and range, while accounting for phylogeny. We found that (i) species with more specialist diets were more neophobic than those with more generalist diets, providing support for the Neophobia Threshold Hypothesis; (ii) migratory species were also more neophobic than nonmigratory species, which supports the Dangerous Niche Hypothesis. Our study shows that the evolution of avian neophobia has been shaped by ecological drivers and demonstrates the potential of Big Team Science to advance our understanding of animal behavior.

Animals↗

PubMed2006

Cues of being watched enhance cooperation in a real-world setting.

We examined the effect of an image of a pair of eyes on contributions to an honesty box used to collect money for drinks in a university coffee room. People paid nearly three times as much for their drinks when eyes were displayed rather than a control image. This finding provides the first evidence from a naturalistic setting of the importance of cues of being watched, and hence reputational concerns, on human cooperative behaviour.

Attitude↗

PubMed2006

Single-trials analyses demonstrate that increases in clock speed contribute to the methamphetamine-induced horizontal shifts in peak-interval timing functions.

INTRODUCTION: Drugs that increase dopamine (DA) transmission have been shown to produce an overestimation of time in duration production procedures as exhibited by horizontal leftward shifts of the psychophysical functions. However, the generality of these results has been inconsistent in the literature. MATERIALS AND METHODS: The present report evaluates the effects of five doses of methamphetamine (MAP) (0.5-1.5 mg/kg, i.p.) on two duration production procedures, the single duration peak-interval (PI) procedure and the multiduration tri-peak procedure in rats. RESULTS: We replicated and extended prior results by showing a dose-dependent proportional overestimation of time that was equivalent on both procedures (i.e., subjects behaved as though they expected reinforcement to be available earlier in real time). Single-trials analyses demonstrated that the reduction in peak rate that is often observed after MAP administration is due to an increase in the proportion of trials in which responding occurred at very low rates and without temporal control. However, these low-rate trials were not the source of the leftward shift in the temporal estimates. Rather, we found that the leftward shift of the PI functions was due to proportional changes in the placement of temporally controlled high-rate responding, which is consistent with a DA-mediated alteration in clock speed.

Animals↗

PubMed2006

Timing in free-living rufous hummingbirds, Selasphorus rufus.

Animals organize their lives around circannual and circadian rhythms, but little is known of their use of much shorter intervals. In the laboratory, some animals can learn the specific duration (seconds or minutes) between periods of food access. It has been supposed that wild nectarivores, such as hummingbirds, might also learn short time intervals so as to avoid revisiting emptied flowers until the nectar has been replenished. We provided free-living, territorial rufous hummingbirds each with eight artificial flowers containing sucrose solution. Four flowers were refilled 10 min after the bird emptied them, and the other four were refilled 20 min after being emptied. Throughout the day, birds revisited the 10 min flowers significantly sooner than they revisited the 20 min flowers, and return visits to the flowers matched their refill schedules. Hummingbirds remembered the locations and timing of eight rewards, updating this information throughout the day. Not only is this the first time that this degree of timing ability has been shown in wild animals, but these hummingbirds also exhibit two of the fundamental aspects of episodic-like memory (where and when), the kind of memory for specific events often thought to be exclusive to humans.

Animals↗

PubMed2005

Comparative evaluation and its implications for mate choice.

Experiments on decision making by humans show that the choices that we make can be very labile. The magnitude of our preferences, and even our rank ordering of options, can vary according to the number and type of alternatives available for comparison. This apparent irrationality has been argued to result from our use of decision heuristics that have evolved to enable us to choose quickly and efficiently between options differing in multiple attributes. Here, we argue that, because there is also selective pressure for animals to make mating decisions quickly, and because potential mates also differ in multiple attributes, similar decision heuristics might have evolved for mate choice. Following this reasoning, the attractiveness of a given mate will depend on the others with whom he or she is being compared, rather than being an absolute function of his or her underlying quality. We describe some of the ramifications of such comparative evaluation, and argue that it could offer new insights into some of the biggest outstanding problems in mate choice and sexual selection.

Journal Article↗

PubMed2003

Context-dependent foraging decisions in rufous hummingbirds.

A core assumption implicit in economic models of animal choice is that subjects assign absolute utilities to options that are independent of the type and number of alternatives available. Humans sometimes appear to violate this assumption and employ relative, as opposed to absolute, currencies when making choices. Recent evidence suggests that animals too might sometimes employ relative choice mechanisms. We tested this idea by measuring the foraging preferences of rufous hummingbirds (Selasphorus rufus) faced with choices analogous to those in which human use of relative currencies is evident. The birds experienced three treatments: a binary choice between two artificial flower types designated concentration (20 microl, 40% sucrose solution) and volume (40 microl, 20%), and two trinary treatments in which a third decoy option (either concentration decoy: 10 microl, 30% or volume decoy: 30 microl, 10%) was added to the set. The birds' preferences differed significantly across the three treatments. In the trinary treatments, the effect of the decoy options was to increase the preference for the option that dominated the decoy. These results are similar to those reported in the human choice literature, and are compatible with the hummingbirds using a relative evaluation mechanism in decision making.

Animals↗

PubMed2002

Recent advances in our understanding of risk-sensitive foraging preferences.

Many experiments have shown that foraging animals are sensitive to the riskiness, or variance, associated with alternative food sources. For example, when offered a choice of a constant feeding option that always offers three seeds, and a risky option that offers either no seeds or six seeds with equal probability, most animals tested will be either risk-averse or risk-prone, preferring either the fixed or variable option respectively. Whether animals are risk-averse or risk-prone appears to depend on a range of factors, including the energetic status of the forager, the type of variance associated with the feeding options and even the number of feeding options between which the animal is choosing. These behavioural phenomena have attracted much theoretical interest, and a range of different explanations have been suggested, some based on a consideration ofthe psychological mechanisms involved in decision making, and others on a consideration of the Darwinian fitness consequences of risk-averse or risk-prone behaviour for the forager. A brief review of the recent literature on risk-sensitive foraging will be presented, focusing on results from the two experimental systems with which I have been involved: wild rufous hummingbirds (Selasphorus rufus) foraging on artificial flowers; European starlings (Sturnus vulgaris) foraging in operant boxes in the laboratory. It will be argued that to understand the foraging decisions of animals account needs to be taken of both the psychological mechanisms underlying decision-making and the fitness consequences of different decisions for the forager.

Animals↗