Understanding across the senses: cross-modal studies of cognition in cetaceans

Cross-modal approaches to the study of sensory perception, social recognition, cognition, and mental representation have proved fruitful in humans as well as in a variety of other species including toothed whales in revealing equivalencies that suggest that different sensory stimuli associated with objects or individuals may effectively evoke mental representations that are, respectively, object based or individual based. Building on established findings of structural equivalence in the form of spontaneous recognition of complex shapes across the modalities of echolocation and vision and behavior favoring identity echoic–visual cross-modal relationships over associative echoic–visual cross-modal relationships, examinations of transitive inference equivalencies from initially learned associations of visual and acoustic stimuli, and recent work exam- ining spontaneous cross-modal social recognition of individual identity across acoustic and gustatory chemical modalities (i.e., the equivalence relationships among an individual’s characteristics), we examine the history, utility and implications for cross-modal research in cetacean cognition. Drawing from research findings on bottlenose dolphins and beluga whales as well as other species we suggest future directions for cetacean cross-modal research to further illuminate understanding how structural and individual sensory equivalencies lead to object-centered and individual-centered mental representations, as well as to explore the potential for practical applications related to cetacean conservation

Cetaceans have complex brains for complex cognition

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Habitat preferences by individual humpback whale mothers in the Hawaiian breeding grounds vary with the age and size of their calves

We investigated whether calf age and calf size influence habitat choice by humpback whale motherecalf pairs in their breeding grounds. During 1997e2008, we conducted focal follows of motherecalf pairs in Hawaiian waters. Tail-fluke identification photographs and calf lengths (measured through video-grammetry) were obtained. Water depth and sea-bed terrain type were derived from GPS data. Identification photographs were matched so that the habitat choices could be established within breeding seasons. Across 72 motherecalf pairs resighted over various intervals within a breeding season, magnitude of depth change between initial and final sightings increased significantly with resighting interval. There was a significant increase from initial depth to final depth for relatively long resighting intervals (27e51 days), but no significant difference for relatively short resighting intervals (2e26 days). Although there was no preference for sea-bed terrain type by motherecalf pairs at their initial sighting, there was a preference for rugged terrain at their final resighting. A resource selection model indicated that the relative probability of a location being used by a motherecalf pair increased (as a function of water depth and rugged sea-bed terrain type) from initial to final sighting; a finding supported by subsequent tests of habitat preference versus availability. For 96 measured calves, calf length and water depth were positively correlated, even when ordinal day of measurement was controlled for statistically; a finding confirmed by a general linear model that simultaneously investigated the relationship between water depth, sea-bed terrain type, number of escorts, ordinal day and calf size. Thus, both calf age and size influence habitat choice by motherecalf pairs in their breeding grounds. The movement of mothers and their maturing calves into deeper waters where they favour rugged sea-bed terrain appears to be part of a suite of behavioural changes during the pre-migratory phase of residency in the breeding grounds

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Between Commerce and Empire: David Hume, Colonial Slavery, and Commercial Incivility

Eighteenth-century Enlightenment thought has recently been reclaimed as a robust, albeit short-lived, cosmopolitan critique of European imperialism. This essay complicates this interpretation through a study of David Hume’s reflections on commerce, empire and slavery. I argue that while Hume condemned the colonial system of monopoly, war and conquest, his strictures against empire did not extend to colonial slavery in the Atlantic. This was because colonial slavery represented a manifestly uncivil institution when judged by enlightened metropolitan sensibilities, yet also a decisively commercial institution pivotal to the eighteenth-century global economy. Confronted by the paradoxical ‘commercial incivility’ of modern slavery, Hume opted for disavowing the link between slavery and commerce, and confined his criticism of slavery to its ancient, feudal and Asiatic incarnations. I contend that Hume’s disavowal of the commercial barbarism of the Atlantic economy is part of a broader ideological effort to separate the idea of commerce from its imperial origins and posit it as the liberal antithesis of empire. The implications of analysis, I conclude, go beyond the eighteenth-century debates over commerce and empire, and more generally pertain to the contradictory entwinement of liberalism and capitalism

The Synergy of Laboratory and Field Studies of Dolphin Behavior and Cognition

Dolphin behavior and cognition have been studied in both the laboratory and the wild. Laboratory studies provide high levels of control over experimental variables and the opportunity to investigate the cognitive mechanisms of behavior. However, laboratory studies are typically limited to a few subjects. Field studies have the benefit of examining behavior and social interactions among large numbers of individuals. They can reveal how cognitive abilities are expressed naturally, and can provide external validity for observations in the laboratory. However, there is typically less controlover experimental variables in field studies than in the laboratory. Thus, a synergistic relationship has emerged between laboratory and field studies of dolphin behavior and cognition with each contributing information and ideas to the other that can lead to new questions and insights. This relationship is demonstrated using four issues: a) the types of percepts and mental representations dolphins can form through echolocation; b) the complexity of relationships that dolphins can understand; c) the dolphin's competency in symbolic referential communication; and d) the dolphin's ability to manage joint attention through pointing and gazing