Article Review; Chickens Prefer Beautiful Humans
This paper entails a summary of the main points raised in the article ‘Chickens Prefer Beautiful Humans’ by Ghirlanda, Jansson, and Enquist.
Summary of the article
The article presents the results of an experiment conducted with the purpose of investigating whether chickens can distinguish human faces as humans do. The experiment is based on the concept that sexual signals provide individuals with a clue about the appropriateness of an individual as a potential mate (Kauth, 2013). The researchers trained chickens to react to human faces. Hens were rewarded for pecking the male face and cocks were rewarded for pecking the female faces at first. In conducting the experiment six chickens were trained. The stimuli are a set of seven faces. These faces are obtained by averaging 35 individual photos of individual of each sex. In the set of seven faces, two faces showing exaggerated male traits are presented on the left and female traits on the right. In the training, chickens are only shown with the average male and female faces. The chicken are rewarded with food for pecking the correct faces, viz. the cocks were rewarded for pecking the female faces while the hens were rewarded for pecking the male faces. The rationale for using male and female faces is to evaluate the variation in behavior between hens and cocks.
The training was conducted until the total number of correct picks correct reach at least 75%. During the experiment, one of the seven faces was randomly presented to the chickens for 10 seconds and the number of pecks was recorded. There was no reinforcement during the test session. This ensured that the behavior of the chicken was not influenced in any way. When the unrewarded faces were presented to the animals, the hens did respond by pecking the face despite the face staying on the touch-sensitive computer screen for 10 seconds. This indicates that the hens had developed cognizance of the faces in relation to depending on their sexual signaling. The hens’ behavior was aligned with human sexual preferences for pecking the face (Fors, 2006).
In addition to conducting the study on chicken, the study further involved undertaking a review on humans. Fourteen (14) undergraduate students, comprising male and female students, were selected to participate in the same experiment. The same sets of 7 faces were used as the stimuli. However, no training was applied to studying human behavior. The humans were required to pick the faces that they would prefer to date. For the test session, students are required to rate all seven faces on the scale. The total scores then are transformed into relative scores to compare with the animal data.
Result
The test results indicate the existence of a strong similarity between humans and chickens with regard to sexual preferences. Human and chicken behavior towards the human faces were almost identical as indicated by the strong degree of correlation between the two gradients on the test on humans and the test on chicken (r2 = 0.98). Figure 1 indicates the existence of a strong correlation between the humans’ and chickens’ responses to the stimuli. Therefore, the experiment results showed that hens depicted behavior similar to that of human beings. Thus, the selection of human faces by the chicken and humans involved in the study was based on assessing the quality of human faces. For example, the animals selected human faces in line with their sexual preferences. According to Benecke (2002), the experiment conducted by Ghirlanda, Jansson, and Enquist underlines the fact that ‘faces not only tell us about the phenotypes of potential mates but also a great deal of their genotypes’ (p.1).
Proportion of responses
Moreover, the results with regard to chicken and human data under the two tests did not differ significantly. In the study, two-sample t-tests, viz., N1 = 6, N2 = 14, were considered. The P values in the two sample tests were 0.35 and 0.98 respectively. The two curves in the graph above have similar gradients, which indicate that chicken and human behavior with reference to sexual signaling are almost similar.
Evaluation of the article
The experiment outlined in the article underlines fundamental concepts of learning and memory. Amongst the notable concepts of learning evidenced in the paper entails the concept of reinforcement learning and associative learning. According to Sutton (2012), reinforcement learning entails learning from mapping situations to respond to in an effort to maximize the chances of being rewarded. Similarly, the hens’ behavior further underlines the contribution of the concept of associative learning in influencing change in behavior(Abrahams, 2004). The concept of associative learning postulates that changes in behavior among individuals and animals occur when an unconditioned stimulus is biologically meaningful (Jensen, 2009). This means that individual or animals engage in a particular behavior depending on whether they intend to undertake a particular action or avoid it. Thus, the expected outcome associated with engaging in a particular behavior either reinforces the subject’s motivation to either act or avoid acting in a particular way (Hasselt, 2011). For example, in the event that the chances of animals are being rewarded with food for engaging in a particular behavior, they are more likely to engage in such behavior. This aspect is underlined by the fact that the hens associated pecking the right human face image with the chance of being rewarded with food. Thus, the food acted as a reinforcer. Similarly, if a negative reinforcement is applied, the animals are likely to behave in a manner that is likely to avoid the negative reinforcement. For example, horses are likely to avoid negative physical pressure applied by the rider during training by responding as expected (Jensen, 2009). Therefore, individuals or animals are likely to depict a particular behavior if they associate the behavior with a particular outcome (Jensen, 2009).
Gariepy (2014) emphasizes the findings of past studies involving animals that ‘birds are capable of learning sequence of events and they can use this knowledge to predict future rewarding events that they have yet to experience’ (p.65). This finding is consistent with the findings of the experiment conducted, which indicate that the chickens consistently pecked their preferred image of the human face in anticipation of being rewarded. There is a further argument related to the agreement between humans and chickens and it is concluded that there is no deviation from the general rules that are present in our human data. The results do not show a necessity for face-specific adaptations in humans.
The experiment further underlines how learning occurs amongst individuals and animals through the application of the concept of social learning. According to Jensen (2009), social learning fosters the acquisition of new knowledge. Jensen (2009) further accentuates that ‘social learning occurs when a naïve animal (the observer) acquires information from a knowledgeable conspecific (the demonstrator), resulting in faster or more effective learning by the observer’ (p.66). However, to enhance social learning, the demonstrator can incorporate a stimulus. The concept of social learning is largely employed in teaching new behavior to domestic animals (Wisdom, Song & Goldstone, 2013). Some domestic animals depict a high level of social learning. For example, hens peck the ground and employ staccato food calls in the quest to attract chicks to food. This behavior is mainly evident if the food is of high quality (Jensen, 2009). This aspect is consistent with the study’s findings which showed that the cocks were attracted to the female human face, which they perceived to be attractive while the hens were attracted to the male human faces.
The study results further underline the fact that the concept of attractiveness is not only comprised of social constructs but is also influenced by the nervous system, which is underlined by the chickens’ behavior toward human faces. This aspect is further supported by Ghirlanda, Jansson, and Enquist (2004), who accentuates that ‘receivers get some information from sexual signals; however, finer details of receiver’s preferences are due to biases inherent to nervous system’ (p. 2).
The article further underlines the application of the concept of discrimination learning. Under the concept of discrimination learning, learning occurs when human beings or animals portray a particular behavior in the presence of a particular stimulus but not in the presence of a particular stimulus (Zonneveld & Chong, 2011). According to Jensen (2009), discrimination enables individuals and animals to fine-tune their behavior according to the prevailing environmental cues. For example, a dog may learn to back in the event that the volume of the television is put off and not when it is on. This aspect indicates that the prevailing environmental aspects play a fundamental role in controlling behavior.
In the process of conducting the study, the hens and humans involved in the study responded in a similar way in selecting the human faces. The experiment presented in the article further underlines the importance of discriminative training in the quest to understand behavior. The principle of discriminative training was applied by displaying the images to the animals and humans simultaneously. On the basis of discriminative training, the animals and human beings involved in the experiment were able to discriminate between the sexes of the subjects on the basis of their facial appearance.
The article recommends the importance of improving the experiment by adjusting the characteristic of the stimuli. The authors recommend the integration of a wider set of faces by incorporating the faces of children and elderly persons in order to understand their preferences. The authors are of the view that conducting such an experiment will play a fundamental role in improving our understanding of the correlation between individuals’ and animals’ behavior with regard to preference for sexuality.
Conclusion
The experiment presented in the article presents critical insight into how learning occurs. This outcome is achieved by examining the behavior of animals (hens) and human beings toward human faces. The experiment illustrates the existence of a strong correlation between the behavior of human beings and animals with regard to learning. The article highlights that learning among individuals and animals can be enhanced by integrating the different concepts of learning. Some of the concepts of learning highlighted in the article include social learning, discriminative learning, and reinforcement learning. Application of these concepts of learning is evidenced by the behavior depicted by animals and human beings involved in the study in response to change in the environmental. Additionally, the paper highlights the significance of integrating stimuli such as rewards in enhancing the learning or development of a particular behavior. The stimuli play a fundamental role in reinforcing or deterring the subjects’ involvement in a particular behavior.
References
Abrahams, M. (2004). Ig Nobel prizes; why chickens prefer beautiful humans. New York:
Routledge.
Benecke, M. (2002). Coding or non-coding is the question.
Cox, C. (2014). Today in unattainable beauty standards; do chickens think I am pretty?
Fors, C. (2006). Hens; why women are different. London: Infinity Publishing.
Gariepy, J., Watson, K., Du, E., Xie, D., Erb, J., & Amasino, D. (2014). ‘Social learning in
humans and other animals’, Frontiers in Science, 8 (58).
Ghirlanda, S., Jansson, L., & Enquist, M. (2004). Chicken prefer better humans. Stockholm:
Stockholm University.
Hasselt, H. (2011). Insight in reinforcement learning; formal analysis and empirical
evaluation of temporal difference learning. Utrecht: Universiteit Utrecht.
Jensen, P. (2009). The ethology of domestic animals; an introductory text. Cambridge, MA:
CABI.
Kauth, M. (2013). Handbook on the evolution of human sexuality. New York: Routledge.
Sutton, R. (2012). Reinforcement learning. New York: Springer.
Wisdom ,T., Song X., & Goldstone R. (2013). ‘Social learning strategies in networked
groups’, Cogn. Sci., 37, 1383–1425
Zonneveld, K., & Chong, I. (2011). ‘Discrimination learning’, Encyclopedia of Child
Behavior and Development, 8 (3), 509-509.
