Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Citation classic - optimal foraging - a selective review of theory and tests

In many everyday situations, our senses are bombarded by many different unisensory signals at any given time. To gain the most veridical, and least variable, estimate of environmental stimuli/properties, we need to combine the individual noisy unisensory perceptual estimates that refer to the same object, while keeping those estimates belonging to different objects or events separate. How, though, does the brain “know” which stimuli to combine? Traditionally, researchers interested in the crossmodal binding problem have focused on the roles that spatial and temporal factors play in modulating multisensory integration. However, crossmodal correspondences between various unisensory features (such as between auditory pitch and visual size) may provide yet another important means of constraining the crossmodal binding problem. A large body of research now shows that people exhibit consistent crossmodal correspondences between many stimulus features in different sensory modalities. For example, people consistently match high-pitched sounds with small, bright objects that are located high up in space. The literature reviewed here supports the view that crossmodal correspondences need to be considered alongside semantic and spatiotemporal congruency, among the key constraints that help our brains solve the crossmodal binding problem.

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Crossmodal correspondences: A tutorial review

BACKGROUND: Childhood maltreatment is the most important preventable cause of psychopathology accounting for about 45% of the population attributable risk for childhood onset psychiatric disorders. A key breakthrough has been the discovery that maltreatment alters trajectories of brain development. METHODS: This review aims to synthesize neuroimaging findings in children who experienced caregiver neglect as well as from studies in children, adolescents and adults who experienced physical, sexual and emotional abuse. In doing so, we provide preliminary answers to questions regarding the importance of type and timing of exposure, gender differences, reversibility and the relationship between brain changes and psychopathology. We also discuss whether these changes represent adaptive modifications or stress-induced damage. RESULTS: Parental verbal abuse, witnessing domestic violence and sexual abuse appear to specifically target brain regions (auditory, visual and somatosensory cortex) and pathways that process and convey the aversive experience. Maltreatment is associated with reliable morphological alterations in anterior cingulate, dorsal lateral prefrontal and orbitofrontal cortex, corpus callosum and adult hippocampus, and with enhanced amygdala response to emotional faces and diminished striatal response to anticipated rewards. Evidence is emerging that these regions and interconnecting pathways have sensitive exposure periods when they are most vulnerable. CONCLUSIONS: Early deprivation and later abuse may have opposite effects on amygdala volume. Structural and functional abnormalities initially attributed to psychiatric illness may be a more direct consequence of abuse. Childhood maltreatment exerts a prepotent influence on brain development and has been an unrecognized confound in almost all psychiatric neuroimaging studies. These brain changes may be best understood as adaptive responses to facilitate survival and reproduction in the face of adversity. Their relationship to psychopathology is complex as they are discernible in both susceptible and resilient individuals with maltreatment histories. Mechanisms fostering resilience will need to be a primary focus of future studies. Language: en

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Annual Research Review: Enduring neurobiological effects of childhood abuse and neglect

Sensory expectations based on product-extrinsic food cues: An interdisciplinary review of the empirical evidence and theoretical accounts

Color is a ubiquitous perceptual stimulus that is often considered in terms of aesthetics. Here we review theoretical and empirical work that looks beyond color aesthetics to the link between color and psychological functioning in humans. We begin by setting a historical context for research in this area, particularly highlighting methodological issues that hampered earlier empirical work. We proceed to overview theoretical and methodological advances during the past decade and conduct a review of emerging empirical findings. Our empirical review focuses especially on color in achievement and affiliation/attraction contexts, but it also covers work on consumer behavior as well as food and beverage evaluation and consumption. The review clearly shows that color can carry important meaning and can have an important impact on people's affect, cognition, and behavior. The literature remains at a nascent stage of development, however, and we note that considerable work on boundary conditions, moderators, and r...

Color Psychology: Effects of Perceiving Color on Psychological Functioning in Humans

In this paper, we review the empirical literature concerning the important question of whether or not food color influences taste and flavor perception in humans. Although a superficial reading of the literature on this topic would appear to give a somewhat mixed answer, we argue that this is, at least in part, due to the fact that many researchers have failed to distinguish between two qualitatively distinct research questions. The first concerns the role that food coloring plays in the perception of the intensity of a particular flavor (e.g., strawberry, banana, etc.) or taste attribute (e.g., sweetness, saltiness, etc.). The second concerns the role that food coloring plays in the perception of flavor identity. The empirical evidence regarding the first question is currently rather ambiguous. While some researchers have reported a significant crossmodal effect of changing the intensity of a food or drink’s coloring on people’s judgments of taste or flavor intensity, many others have failed to demonstrate any such effect. By contrast, the research findings concerning the second question clearly support the view that people’s judgments of flavor identity are often affected by the changing of a food or drink’s color (be it appropriate, inappropriate, or absent). We discuss the possible mechanisms underlying these crossmodal effects and suggest some of the key directions for future research in order to move our understanding in this area forward.

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Does Food Color Influence Taste and Flavor Perception in Humans

Grape expectations: the role of cognitive influences in color-flavor interactions.

Does what we hear influence our perception of, and behaviors toward, food and drink? If so, what are the mechanism(s) underlying these cross-modal effects? While many people intuitively believe that our sense of hearing has little influence on our experiences of foodstuffs, the evidence that has been published to date suggests that this is not always the case. In this article, we review the growing body of empirical research demonstrating that what we hear can affect our perception of, and responses to, food and drink. We review both laboratory-based research and real-world (ecological) studies of the effects of music and other auditory stimuli on people's food-related behaviors. This research has revealed that what we hear (be it music, the sounds we make while eating, or even pure tones or bursts of white noise) can have a dramatic effect on our perceptions of food and drink. Auditory stimuli influence people's consumption rates, their preference ratings and their flavor assessments, and have even been shown to significantly impact on the overall amount that people consume. We highlight a number of explanations, including multisensory integration, attention, associative learning and expectations, that have all been put forward in order to account for these cross-modal effects.

PRACTICAL APPLICATIONS
This manuscript examines the relationship between what people hear and their food and drink experiences, perceptions and behaviors. In previous research, auditory cues have been shown to influence people's purchasing decisions, flavor evaluations and their consumption rates of food and drink. The multisensory approach inherent to this line of research provides a means of enhancing culinary experiences for people in the years to come. In fact, some important practical interventions have already been made. For example, the Fat Duck restaurant in Bray, England serves a “sounds of the sea” seafood dish. Those who select this dish are presented with a plate of seafood that is reminiscent of a beach, with an iPod (hidden in a seashell with the earphones poking out) that plays a “sounds of the sea” soundtrack. Innovations such as these, based on a solid understanding of the cognitive psychology and neuroscience of multisensory integration, may increasingly help to heighten our enjoyment and experience of food and drink.

The influence of auditory cues on the perception of, and responses to, food and drink

Previous research that has manipulated either the color of, or labeling information associated with, foods and beverages has shown that each of these factors can significantly influence perceptual and preferential responses to them. The present study examined how the simultaneous manipulation of these two cues (color and label) affects perception of, and hedonic responses to, flavor. Thirty participants rated 12 chocolate M&Ms (identical aside from their color), described as coming from a “new line of chocolate products,” for the intensity of their chocolate flavors (“chocolatey-ness”) and their hedonic qualities (“likeability”). In the color-only condition, sighted participants received two green and two brown M&Ms. In the label-only condition, blindfolded participants received two M&Ms that were labeled as being from a “milk chocolate category” and two M&Ms that were labeled as being from a “dark chocolate category.” In the color–label condition, sighted participants received an M&M of each of the four possible color–label combinations. The participants rated brown M&Ms as being significantly more chocolatey than green M&Ms and “dark chocolate”-labeled M&Ms as being significantly more chocolatey than “milk chocolate”-labeled ones. No such effects were observed for the likability data. There was no interaction between the color and label factors. These results illustrate that flavor perception involves the combining of chemosensory information with both visual (color) information and cognitive, expectancy-based (label) inputs.

The Influence of Color and Label Information on Flavor Perception

Neural activity in the striatum has consistently been shown to scale with the value of anticipated rewards. As a result, it is common across a number of neuroscientific subdiscliplines to associate activation in the striatum with anticipation of a rewarding outcome or a positive emotional state. However, most studies have failed to dissociate expected value from the motivation associated with seeking a reward. Although motivation generally scales positively with increases in potential reward, there are circumstances in which this linkage does not apply. The current study dissociates value-related activation from that induced by motivation alone by employing a task in which motivation increased as anticipated reward decreased. This design reverses the typical relationship between motivation and reward, allowing us to differentially investigate fMRI BOLD responses that scale with each. We report that activity scaled differently with value and motivation across the striatum. Specifically, responses in the caudate and putamen increased with motivation, whereas nucleus accumbens activity increased with expected reward. Consistent with this, self-report ratings indicated a positive association between caudate and putamen activity and arousal, whereas activity in the nucleus accumbens was more associated with liking. We conclude that there exist regional limits on inferring reward expectation from striatal activation.

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Maya U. Shankar

Papers

Does Food Color Influence Taste and Flavor Perception in Humans

Grape expectations: the role of cognitive influences in color-flavor interactions.

The influence of auditory cues on the perception of, and responses to, food and drink

The Influence of Color and Label Information on Flavor Perception

Dissociating motivation from reward in human striatal activity