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The "Clever Hans Phenomenon" revisited.

Samhita L, Gross HJ - Commun Integr Biol (2013)

Bottom Line: In the first decade of the 20th century, a horse named Hans drew worldwide attention in Berlin as the first and most famous "speaking" and thinking animal.Hans solved calculations by tapping numbers or letters with his hoof in order to answer questions.This observation caused a revolution and as a consequence, experimenters avoided strictly any face-to-face contact in studies about cognitive abilities of animals-a fundamental lesson that is still not applied rigorously.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Cell Biology; Indian Institute of Science; Bangalore, India.

ABSTRACT
In the first decade of the 20th century, a horse named Hans drew worldwide attention in Berlin as the first and most famous "speaking" and thinking animal. Hans solved calculations by tapping numbers or letters with his hoof in order to answer questions. Later on, it turned out that the horse was able to give the correct answer by reading the microscopic signals in the face of the questioning person. This observation caused a revolution and as a consequence, experimenters avoided strictly any face-to-face contact in studies about cognitive abilities of animals-a fundamental lesson that is still not applied rigorously.

No MeSH data available.


Related in: MedlinePlus

Figure 2. “Clever Hans” in action, tapping with his hoof: 8 – 4 = 4, 8 + 4 = 12, 8 / 4 = 2, and 8 x 4 = 32.
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Figure 2: Figure 2. “Clever Hans” in action, tapping with his hoof: 8 – 4 = 4, 8 + 4 = 12, 8 / 4 = 2, and 8 x 4 = 32.

Mentions: A recent study repeated the same error as was seen in the “Clever Hans” case,4,5 emphasizing the need to remember that lesson. Those studies implied that the numerical cognition of elephants differs from and is superior to that of all other animals.10,11 The experiments indicated that elephants defy the famous Weber’s Law (published around 1834 in Latin). The law states thatthe ability of an animal (or human) to discriminate between two quantities is a function of their ratios rather than the absolute difference between them. The study was soon criticized because of methodological deficits12,13 and the experiments were reproduced such that neither the experimenter nor the mahout (elephant keeper) knew where and how many pieces of food had been hidden. In summary, the major deficit10,11 was the neglect of the lesson we learned from “Clever Hans”: a semi transparent screen between the mahout and the food barrels, respectively, and the elephants, would have yielded correct results. That is, that elephants, like other animals, including humans, use an accumulator model in accordance with Weber’s Law. This study and others like it call for a revival of the memory of Clever Hans. (Figs. 1 and 2)


The "Clever Hans Phenomenon" revisited.

Samhita L, Gross HJ - Commun Integr Biol (2013)

Figure 2. “Clever Hans” in action, tapping with his hoof: 8 – 4 = 4, 8 + 4 = 12, 8 / 4 = 2, and 8 x 4 = 32.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921203&req=5

Figure 2: Figure 2. “Clever Hans” in action, tapping with his hoof: 8 – 4 = 4, 8 + 4 = 12, 8 / 4 = 2, and 8 x 4 = 32.
Mentions: A recent study repeated the same error as was seen in the “Clever Hans” case,4,5 emphasizing the need to remember that lesson. Those studies implied that the numerical cognition of elephants differs from and is superior to that of all other animals.10,11 The experiments indicated that elephants defy the famous Weber’s Law (published around 1834 in Latin). The law states thatthe ability of an animal (or human) to discriminate between two quantities is a function of their ratios rather than the absolute difference between them. The study was soon criticized because of methodological deficits12,13 and the experiments were reproduced such that neither the experimenter nor the mahout (elephant keeper) knew where and how many pieces of food had been hidden. In summary, the major deficit10,11 was the neglect of the lesson we learned from “Clever Hans”: a semi transparent screen between the mahout and the food barrels, respectively, and the elephants, would have yielded correct results. That is, that elephants, like other animals, including humans, use an accumulator model in accordance with Weber’s Law. This study and others like it call for a revival of the memory of Clever Hans. (Figs. 1 and 2)

Bottom Line: In the first decade of the 20th century, a horse named Hans drew worldwide attention in Berlin as the first and most famous "speaking" and thinking animal.Hans solved calculations by tapping numbers or letters with his hoof in order to answer questions.This observation caused a revolution and as a consequence, experimenters avoided strictly any face-to-face contact in studies about cognitive abilities of animals-a fundamental lesson that is still not applied rigorously.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Cell Biology; Indian Institute of Science; Bangalore, India.

ABSTRACT
In the first decade of the 20th century, a horse named Hans drew worldwide attention in Berlin as the first and most famous "speaking" and thinking animal. Hans solved calculations by tapping numbers or letters with his hoof in order to answer questions. Later on, it turned out that the horse was able to give the correct answer by reading the microscopic signals in the face of the questioning person. This observation caused a revolution and as a consequence, experimenters avoided strictly any face-to-face contact in studies about cognitive abilities of animals-a fundamental lesson that is still not applied rigorously.

No MeSH data available.


Related in: MedlinePlus