The sound is a warning to every other crow: Frédéric Jiguet, a tall ornithologist whose dark hair is graying around the ears, has shown up for work. As Jiguet walks to his office at the French National Museum of Natural History, which is on the garden's grounds, dozens of the black vandals take to the trees and rain abuse on him, as though he were a condemned man. "I think I'm the best friend of French crows," Jiguet told me. "But I am probably the man they hate most." Crows are famous for holding grudges.

In the late 19th and early 20th centuries, Charles Henry Turner (1867–1923) established a research program that was in sharp contrast to prevailing ideas regarding animal behavior and cognition. Despite facing almost insurmountable barriers because of his African American ethnicity, he published more than 70 papers, including several in Science ([ 1 ][1]–[ 3 ][2]), on comparative brain anatomy in birds and invertebrates, individual variation of behavior and learning competences, and intelligent problem-solving in a large variety of animals, at a time when the dominant ideas only credited animals with the simplest of learning abilities. But his discoveries and conceptual advances failed to gain the recognition they deserved, and his works were later all but forgotten—indeed, some recent animal cognition research has reinvented wheels that had already been fashioned by Turner. Charles Darwin (1809–1882) and George Romanes (1848–1894) were famously generous in attributing intelligent behavior and mental abilities to animals, but their musings were largely based on observation and inference. The predominant experimentalist theories of animal behavior in the early 20th century, however, largely rejected notions of advanced animal intelligence or insight. Early ethologists such as Oskar Heinroth, Charles Whitman, and Wallace Craig focused instead on innate behavior and imprinting, a simple form of learning. Where problem-solving was observed, such as when animals open puzzle boxes, behaviorists such as Edward Thorndike proposed that this materialized as a result of trial and error, not insight or understanding of the nature of the challenge. None of these scientists were interested in individual variation of behavior. Enter Charles H. Turner, who took seriously Darwin's assertion of the importance of individual variation as well as the idea that humans were not the only intelligent animal species. But Turner backed up this possibility with a rigorous experimental approach. Turner was born just 2 years after the end of slavery in the United States in 1865. He obtained his M.Sc. from the University of Cincinnati in 1892 ([ 4 ][3]). In the same year, the 25-year-old published two single-author papers in Science —one of which was a short version of his B.Sc. work on the comparative anatomy of bird brains, whose relative size and complexity he compared with those of reptiles ([ 1 ][1]). Turner's verdict was, “When we compare the brain of a crow or a titmouse with the brain of a snake or a turtle, it is no longer a marvel that birds bear towards their reptilian cousins the relation of intellectual giants to intellectual dwarfs” [([ 1 ][1]), p. 16]. The same year also saw the publication of another remarkable study on variations in web building by gallery spiders ([ 5 ][4]) that contained key ingredients of Turner's distinct interpretation of animal behavior that was to accompany his entire body of work. Like many of his future papers, the study interfaces careful field observations with meticulously controlled laboratory work. Contrary to the still-popular view that spider web construction is a prime example of invertebrates' robotic, repetitive action patterns, Turner reported variation between individuals in adapting their construction to the geometry of available space and the functionality in capturing prey: “we may safely conclude that an instinctive impulse prompts gallery spiders to weave gallery webs, but the details of the construction are the products of intelligent action” [([ 5 ][4]), p. 110]. In the year of his Ph.D. (1907), Turner published on associative and spatial learning in ants and reported individual learning curves of their performance ([ 6 ][5]). Turner's focus on individual differences in behavior is a constant theme in his studies. It is deplorable that the now-popular field of “animal personality” has taken so little notice of Turner's trailblazing approach. The list of Turner's discoveries and insights that should have garnered attention, but did not, is long. Every student of animal behavior knows Nikolaas Tinbergen's study from 1932 on spatial learning, in which the later Nobel laureate (awarded for studies of individual and social behavior in animals) first marked a beewolf 's nest entrance with pine cones, then moved them to demonstrate that the insect was guided by a memory of the landmarks ([ 7 ][6]). But it is mostly unknown that Turner had already published similar findings in 1908, observing a solitary burrowing bee whose nest entrance was close to a discarded Coca Cola bottle cap. When the cap was moved to a nearby location next to an artificial burrow that Turner had made, the bee crawled into that burrow without hesitation—indicating, just as in Tinbergen's experiments, that the insect had a memory for landmarks rather than, for example, being guided by an instinct to follow the scent of the nest ([ 8 ][7]). In 1912, in a study that explored how a prey-carrying walking wasp finds its way home around obstacles in the path, Turner explicitly confronted Thorndike, affirming that the wasp's behavior is not explicable by trial-and-error learning and is instead consistent with a form of intentionality and an awareness of the desired outcome of the wasp's actions ([ 9 ][8]). Moreover, Turner found that an ant stuck on a small island began assembling a bridge to the “mainland,” using three different materials ([ 10 ][9]). The ant's behavior could not easily be explained by then-popular notions of instinct or trial-and-error learning; instead, the ant appeared to appreciate the nature of the problem, imagined a solution, and then worked toward this goal. The view that animals are capable of insightful problem-solving was also apparent in Turner's interpretation of his field observations of the hunting behavior of a snake pursuing a lizard ([ 3 ][2]). The lizard had escaped up a tree and looked downward where it expected the snake to launch the next attack. The snake, which had been pursuing the lizard for some time, instead ascended another tree, crossed over when it had reached a point higher than the lizard, and then attacked from behind. These observations are reminiscent of the detour behavior seen when jumping spiders hunt—discovered in the 1990s ([ 11 ][10]). It is remarkable that Turner's views on animal intentionality preceded present-day explorations of the same topic by a century. Even though his experimental work was known to contemporary giants such as John Watson and Thorndike ([ 4 ][3]) and across the Atlantic by later Nobel laureate Karl von Frisch, Turner's visionary ideas about animal intelligence did not resonate in the field; perhaps they were simply too far ahead of the time. Accordingly, they are almost completely unrecognized in the current literature. Further highlighting the importance and insightful nature of Turner's work, in 1913 he reported on the effects of age and sex on cockroaches trained to navigate mazes ([ 12 ][11]). Turner found that individuals placed an emphasis on either speed or accuracy: Older cockroaches choose slowly but more precisely. Extraordinarily, Turner suggests that the hesitation that cockroaches display when evaluating their options bears the hallmarks of will, a facet of consciousness. The question of whether humans and other animals exhibit free will continues to generate controversy among neuroscientists and philosophers. That insights from insect behavior could contribute to this debate has only recently been suggested again by neuroscientist Martin Heisenberg ([ 13 ][12]), who proposed that insects display an awareness of the consequences of their actions and evidence of free will in deciding between options. ![Figure][13] From Charles H. Turner to comparative cognition: 1850–2020 Charles H. Turner made important observations about animal cognition, which went against the leading paradigms of the time. His ideas have stood the test of history, but Turner's work has largely been forgotten, likely because his ethnicity prevented him from becoming a research team leader and so he could not train scientists who might have continued his approach. Turner was active in the U.S. civil rights movement and advocated that education is key to overcoming ethnic barriers in society. GRAPHIC: V. ALTOUNIAN/ SCIENCE ; (IMAGES, CLOCKWISE FROM LEFT) WIKIMEDIA COMMONS;C. H. TURNER ET AL. ([ 12 ][11]); ST. LOUIS GLOBE-DEMOCRAT , 3 JULY 1917, P. 1 Why is Turner not more widely credited as a major luminary in research on animal intelligence? Turner faced substantial obstacles because of his ethnicity. Despite publishing many important papers, he was not given a post at a major U.S. research university. Turner's work was thus conducted without access to state-of-the-art laboratory facilities or library resources. One reason for Turner's relative obscurity today may be that he had no possibility of mentoring research students who would have carried his ideas into subsequent generations. For comparison, Russian Nobel laureate Ivan Pavlov (1849–1936), famed for his studies on classical conditioning, trained more than 140 co-workers. One cannot help but wonder what Turner might have achieved if he had had comparable resources and manpower. The entire field of animal cognition may have developed differently. Would a “cognitive revolution” have been needed against the dominant ideas of behaviorism that ruled psychology for the first half of the 20th century (postulating that learning largely happens in the form of simple associations), if Turner's ideas about advanced cognition in animals had generated a movement at the time he expressed them? African American historian William Du Bois (1868–1963) lamented that “C. H. Turner, one of the great world authorities on insects, nearly entered the faculty of Chicago University; but the head professor who called him died, and his successor would not have a “N\---|--,” despite a reputation which was European; Turner died in a high school of neglect and overwork” [([ 4 ][3]), p. 348]. The institution at which Turner taught from 1908 to 1922 was Sumner High School, a school for African American children in St. Louis. During his time there, he and his pupils would have witnessed the East St. Louis massacre in 1917, during which white mobs murdered more than 100 African Americans; another 6000 lost their homes as a result of arson attacks on their neighborhoods ([ 14 ][14]). Turner was active in the U.S. civil rights movement, and years before coming to St. Louis, he wrote that an emphasis on high-quality education and a conscious effort to abandon prejudices might eliminate barriers between Blacks and whites within a few decades ([ 15 ][15]). One would hope that nowadays, a person of Turner's caliber might not face similar adversity in terms of academic employment opportunities or long-term recognition of their contribution to science. But even today, very few scholars in animal cognition, or indeed across biology, are Black. Turner clearly recognized the importance of ethnic-minority role models from the earliest stages of education; their near-complete absence in a field of scholarly study will require concerted counterefforts. Funded summer schools for ethnic minority students can also make a substantial difference to inspire budding scientists. Institutions must make still-stronger efforts to eliminate biases in hiring, promotions, and salary decisions and to celebrate the successes of ethnic minority scholars. Even where they do (and there is likely plenty of room for improvement), overt or poorly concealed racism is still commonly experienced by underrepresented ethnic groups, even in academia. This will likely discourage many aspiring scientists from venturing further. A hopeful development is that some conference organizers are taking steps in the right direction to increase inclusivity; for example, the Animal Behavior Society annually supplies the Charles H. Turner award that prioritizes traditionally underrepresented groups for conference travel funding. More than ever, humanity needs to be inclusive to confront current and future challenges. Diversity increases the pool of talent and, as Turner's example shows, has the potential to transform entire fields. 1. [↵][16]1. C. H. Turner , Science 19, 16 (1892). [OpenUrl][17][CrossRef][18][PubMed][19] 2. 1. C. H. Turner , Science 20, 39 (1892). [OpenUrl][20] 3. [↵][21]1. C. H. Turner , Science 30, 563 (1909). [OpenUrl][22][FREE Full Text][23] 4. [↵][24]1. C. I. Abramson , Annu. Rev. Entomol. 54, 343 (2009). [OpenUrl][25][CrossRef][26][PubMed][27] 5. [↵][28]1. C. H. Turner , J. Comp. Neurol. 2, 95 (1892). [OpenUrl][29] 6. [↵][30]1. C. H. Turner , J. Comp. Neurol. Psychol. 17, 367 (1907). [OpenUrl][31] 7. [↵][32]1. N. Tinbergen , J. Comp. Physiol. A Neuroethol. Sens. Neural Behav. Physiol. 16, 305 (1932). [OpenUrl][33] 8. [↵][34]1. C. H. Turner , Biol. Bull. 15, 247 (1908). [OpenUrl][35] 9. [↵][36]1. C. H. Turner , Psyche 19, 100 (1912). [OpenUrl][37] 10. [↵][38]1. C. H. Turner , Biol. Bull. 13, 333 (1907). [OpenUrl][39][CrossRef][40] 11. [↵][41]1. M. S. Tarsitano, 2. R. R. Jackson , Behaviour 131, 65 (1994). [OpenUrl][42][CrossRef][43] 12. [↵][44]1. C. H. Turner , Biol. Bull. 25, 348 (1913). [OpenUrl][45] 13. [↵][46]1. M. Heisenberg , Nature 459, 164 (2009). [OpenUrl][47][CrossRef][48][PubMed][49][Web of Science][50] 14. [↵][51]1. J. N. Harrington , Buzzing with Questions: The Inquisitive Mind of Charles Henry Turner (Boyds Mills Press, 2019). 15. [↵][52]1. C. H. Turner , in Twentieth Century Negro Literature (J. L. Nichols, 1902), pp. 162–166. [1]: #ref-1 [2]: #ref-3 [3]: #ref-4 [4]: #ref-5 [5]: #ref-6 [6]: #ref-7 [7]: #ref-8 [8]: #ref-9 [9]: #ref-10 [10]: #ref-11 [11]: #ref-12 [12]: #ref-13 [13]: pending:yes [14]: #ref-14 [15]: #ref-15 [16]: #xref-ref-1-1 "View reference 1 in text" [17]: {openurl}?query=rft.jtitle%253DScience%26rft.volume%253D19%26rft.spage%253D16%26rft_id%253Dinfo%253Adoi%252F10.1126%252Fscience.ns-19.466.16%26rft_id%253Dinfo%253Apmid%252F17774142%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [18]: /lookup/external-ref?access_num=10.1126/science.ns-19.466.16&link_type=DOI [19]: /lookup/external-ref?access_num=17774142&link_type=MED&atom=%2Fsci%2F370%2F6516%2F530.atom [20]: {openurl}?query=rft.jtitle%253DScience%26rft.volume%253D20%26rft.spage%253D39%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [21]: #xref-ref-3-1 "View reference 3 in text" [22]: {openurl}?query=rft.jtitle%253DScience%26rft.stitle%253DScience%26rft.aulast%253DTurner%26rft.auinit1%253DC.%2BH.%26rft.volume%253D30%26rft.issue%253D773%26rft.spage%253D563%26rft.epage%253D564%26rft.atitle%253DTHE%2BBEHAVIOR%2BOF%2BA%2BSNAKE%26rft_id%253Dinfo%253Adoi%252F10.1126%252Fscience.30.773.563%26rft_id%253Dinfo%253Apmid%252F17817501%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [23]: /lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6MzoiUERGIjtzOjExOiJqb3VybmFsQ29kZSI7czozOiJzY2kiO3M6NToicmVzaWQiO3M6MTA6IjMwLzc3My81NjMiO3M6NDoiYXRvbSI7czoyMjoiL3NjaS8zNzAvNjUxNi81MzAuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9 [24]: #xref-ref-4-1 "View reference 4 in text" [25]: {openurl}?query=rft.jtitle%253DAnnual%2Breview%2Bof%2Bentomology%26rft.stitle%253DAnnu%2BRev%2BEntomol%26rft.aulast%253DAbramson%26rft.auinit1%253DC.%2BI.%26rft.volume%253D54%26rft.spage%253D343%26rft.epage%253D359%26rft.atitle%253DA%2Bstudy%2Bin%2Binspiration%253A%2BCharles%2BHenry%2BTurner%2B%25281867--1923%2529%2Band%2Bthe%2Binvestigation%2Bof%2Binsect%2Bbehavior.%26rft_id%253Dinfo%253Adoi%252F10.1146%252Fannurev.ento.54.110807.090502%26rft_id%253Dinfo%253Apmid%252F18817509%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [26]: /lookup/external-ref?access_num=10.1146/annurev.ento.54.110807.090502&link_type=DOI [27]: /lookup/external-ref?access_num=18817509&link_type=MED&atom=%2Fsci%2F370%2F6516%2F530.atom [28]: #xref-ref-5-1 "View reference 5 in text" [29]: {openurl}?query=rft.jtitle%253DJ.%2BComp.%2BNeurol.%26rft.volume%253D2%26rft.spage%253D95%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [30]: #xref-ref-6-1 "View reference 6 in text" [31]: {openurl}?query=rft.jtitle%253DJ.%2BComp.%2BNeurol.%2BPsychol.%26rft.volume%253D17%26rft.spage%253D367%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [32]: #xref-ref-7-1 "View reference 7 in text" [33]: {openurl}?query=rft.jtitle%253DJ.%2BComp.%2BPhysiol.%2BA%2BNeuroethol.%2BSens.%2BNeural%2BBehav.%2BPhysiol.%26rft.volume%253D16%26rft.spage%253D305%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [34]: #xref-ref-8-1 "View reference 8 in text" [35]: {openurl}?query=rft.jtitle%253DThe%2BBiological%2BBulletin%26rft.stitle%253DBiol.%2BBull.%26rft.aulast%253DTURNER%26rft.auinit1%253DC.%2BH.%26rft.volume%253D15%26rft.issue%253D6%26rft.spage%253D247%26rft.epage%253D258%26rft.atitle%253DTHE%2BHOMING%2BOF%2BTHE%2BBURROWING-BEES%2B%2528ANTHOPHORIDAe%2529%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [36]: #xref-ref-9-1 "View reference 9 in text" [37]: {openurl}?query=rft.jtitle%253DPsyche%26rft.volume%253D19%26rft.spage%253D100%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [38]: #xref-ref-10-1 "View reference 10 in text" [39]: {openurl}?query=rft.jtitle%253DThe%2BBiological%2BBulletin%26rft.stitle%253DBiol.%2BBull.%26rft.aulast%253DTURNER%26rft.auinit1%253DC.%2BH.%26rft.volume%253D13%26rft.issue%253D6%26rft.spage%253D333%26rft.epage%253D343%26rft.atitle%253DDO%2BANTS%2BFORM%2BPRACTICAL%2BJUDGMENTS%253F%26rft_id%253Dinfo%253Adoi%252F10.2307%252F1535609%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [40]: /lookup/external-ref?access_num=10.2307/1535609&link_type=DOI [41]: #xref-ref-11-1 "View reference 11 in text" [42]: {openurl}?query=rft.jtitle%253DBehaviour%26rft.volume%253D131%26rft.spage%253D65%26rft_id%253Dinfo%253Adoi%252F10.1163%252F156853994X00217%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [43]: /lookup/external-ref?access_num=10.1163/156853994X00217&link_type=DOI [44]: #xref-ref-12-1 "View reference 12 in text" [45]: {openurl}?query=rft.jtitle%253DThe%2BBiological%2BBulletin%26rft.stitle%253DBiol.%2BBull.%26rft.aulast%253DTURNER%26rft.auinit1%253DC.%2BH.%26rft.volume%253D25%26rft.issue%253D6%26rft.spage%253D348%26rft.epage%253D365%26rft.atitle%253DBEHAVIOR%2BOF%2BTHE%2BCOMMON%2BROACH%2B%2528PERIPLANETA%2BORIENTALIS%2BL.%2529%2BON%2BAN%2BOPEN%2BMAZE%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [46]: #xref-ref-13-1 "View reference 13 in text" [47]: {openurl}?query=rft.jtitle%253DNature%26rft.stitle%253DNature%26rft.aulast%253DHeisenberg%26rft.auinit1%253DM.%26rft.volume%253D459%26rft.issue%253D7244%26rft.spage%253D164%26rft.epage%253D165%26rft.atitle%253DIs%2Bfree%2Bwill%2Ban%2Billusion%253F%26rft_id%253Dinfo%253Adoi%252F10.1038%252F459164a%26rft_id%253Dinfo%253Apmid%252F19444190%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [48]: /lookup/external-ref?access_num=10.1038/459164a&link_type=DOI [49]: /lookup/external-ref?access_num=19444190&link_type=MED&atom=%2Fsci%2F370%2F6516%2F530.atom [50]: /lookup/external-ref?access_num=000266036100016&link_type=ISI [51]: #xref-ref-14-1 "View reference 14 in text" [52]: #xref-ref-15-1 "View reference 15 in text"

In one of Aesop's fables, a thirsty crow finds a pitcher with a small amount of water beyond the reach of its beak. After failing to push the pitcher over, the crow drops pebbles in one by one until the water level rises, allowing the bird to have a drink. For Aesop, the fable showed the superiority of intelligence over brute strength. Two and a half millennia later, we might get to see whether AI could pass Aesop's ancient intelligence test. In June, researchers will train algorithms to master a suite of tasks that have traditionally been used to test animal cognition.

WASHINGTON - A small tropical reef fish was able to recognize itself in a mirror, scientists said Thursday, in a finding that raises provocative questions about assessing self-awareness and cognitive abilities in animals. The study involved experiments in which the bluestreak cleaner wrasse was given a mirror self-recognition test, a technique developed in 1970 for gauging animal self-awareness. In aquarium experiments at Osaka City University, researchers applied a brown-colored mark on the fish's body in a place that could be seen only in a mirror reflection. The fish tried to remove the marks by scraping their bodies on hard surfaces after watching themselves in a mirror, but never tried to remove them without a mirror present, indicating they understood the reflection was of them, the researchers said. When a transparent, rather than brown, mark was applied, the fish never tried to remove it.

The world is teeming with intelligence, from little wormy grubs in the garden to physicists poring over equations in university offices. In the past few years we've also come to view our virtual assistants as possessing some kind of intelligence--imperfect and sometimes downright creepy, but intelligence nonetheless. A.I. has come a long way since Microsoft's Clippy. Whether we're talking to Siri like a friend or asking our dogs for advice, humans love to imagine other animals' intelligence. As we enter into the infancy of A.I., it's fun to speculate how some existing lifeforms stack up to our best A.I so far.

This article, derived from the 1996 American Association for Artificial Intelligence Presidential Address, explores the notion of intelligence from a variety of perspectives and finds that it "are" many things. It has, for example, been interpreted in a variety of ways even within our own field, ranging from the logical view (intelligence as part of mathematical logic) to the psychological view (intelligence as an empirical phenomenon of the natural world) to a variety of others. One goal of this article is to go back to basics, reviewing the things that we, individually and collectively, have taken as given, in part because we have taken multiple different and sometimes inconsistent things for granted. I believe it will prove useful to expose the tacit assumptions, models, and metaphors that we carry around as a way of understanding both what we're about and why we sometimes seem to be at odds with one another. Intelligence are also many things in the sense that it is a product of evolution.

If you have ever hung a bird feeder in your garden only to find it emptied by a squirrel minutes later, you'll already know the pesky rodents are smart. Now scientists have shown that squirrels can remember problem-solving techniques for long periods and can apply them to new situations. Research found grey squirrels quickly remember how to solve a problem they have not seen for almost two years, and also quickly work out how to use those skills in a redesigned version of the same test. Animal intelligence is generally judged by how well a creature can adapt to its environment and make use of resources around them. Squirrels have shown they can live almost anywhere, by spreading from North America to other regions, including the UK where they have all but replaced the native red squirrel.

In popular books, academic articles, a TED talk, and countless lectures, the prominent Dutch primatologist Frans De Waal has spent his career showing just how many capacities and traits once thought to be distinctly human – from face-recognition to inequality aversion – are in fact broadly shared by many other species of primates. His new book, "Are We Smart Enough To Know How Smart Animals Are" argues that impressive forms of animal intelligence occur throughout the animal kingdom, not simply in the primate order. Our own preconceptions may be the main obstacle to recognizing animal intelligence. Until the 1980s researchers usually described animals with the terms "learning" and "instincts" but not "cognition." That's changed – now almost every week there's a new finding in animal cognition.

This article, derived from the 1996 Association for the Advancement of Artificial Intelligence Presidential Address, explores the notion of intelligence from a variety of perspectives and finds that it "are" many things. It has, for example, been interpreted in a variety of ways even within our own field, ranging from the logical view (intelligence as part of mathematical logic) to the psychological view (intelligence as an empirical phenomenon of the natural world) to a variety of others. One goal of this article is to go back to basics, reviewing the things that we, individually and collectively, have taken as given, in part because we have taken multiple different and sometimes inconsistent things for granted. I believe it will prove useful to expose the tacit assumptions, models, and metaphors that we carry around as a way of understanding both what we're about and why we sometimes seem to be at odds with one another. Intelligence are also many things in the sense that is a product of evolution. Our physical bodies are in many ways overdetermined, unnecessarily complex, and inefficiently designed, that is, the predictable product of the blind search that is evolution. What's manifestly true of our anatomy is also likely true of our cognitive architecture. Natural intelligence is unlikely to be limited by principles of parsimony and is likely to be overdetermined, unnecessarily complex, and inefficiently designed. In this sense, intelligence are many things because is composed of the many elements that have been thrown together over evolutionary timescales. I suggest that in the face of that, searching for minimalism and elegance may be a diversion, for it simply may not be there. Somewhat more crudely put: The human mind is a 400,000-year-old legacy application -- and you expected to find structured programming? I end with a number of speculations, suggesting that there are some niches in the design space of intelligences that are currently underexplored. One example is the view that thinking is in part visual, and hence it might prove useful to develop representations and reasoning mechanisms that reason with diagrams (not just about them) and that take seriously their visual nature. I speculate as well that thinking may be a form of reliving, that re-acting out what we have experienced is one powerful way to think about and solve problems in the world. In this view, thinking is not simply the decontextualized manipulation of abstract symbols, powerful though that may be. Instead, some significant part of our thinking may be the reuse or simulation of our experiences in the environment. In keeping with this, I suggest that it may prove useful to marry the concreteness of reasoning in a model with the power that arises from reasoning abstractly.