Student Scholarship

Document Type

Research Paper

Abstract

This document explores the striking similarities between the behavioral and developmental patterns of infant rhesus monkeys and human infants, specifically focusing on the detrimental effects of social and maternal deprivation. A significant portion of the research presented is derived from the laboratory experiments of Harry Harlow, who utilized surrogate mothers made of wire or cloth to study the origins of affectional patterns. These studies identified three primary primate reflexes—the contact-clasp, righting, and sucking reflexes—that establish the initial tie between mother and infant. The research demonstrates that "contact comfort" provided by a cloth surrogate acts as a psychological base of operations, allowing infants to overcome fear and engage in essential exploratory behavior. 

In contrast, rhesus monkeys subjected to total or partial social isolation develop severe abnormalities, including aggression, impaired sexual behavior, and physiological changes like excessive eating and drinking. The document parallels these findings with data on human infants who experience maternal deprivation through institutionalization or separation. Such children often exhibit intellectual retardation, language deficits, and social disturbances, such as "affect hunger" or social apathy. While human experiments are restricted by ethical reasons, researchers argue that monkey behavior serves as a vital comparative model for understanding human development. The cumulative evidence suggests that the presence of a consistent mother-figure and opportunities for social interaction are critical for normal personal-social functioning in both species. Ultimately, the document emphasizes the need for continued research into environmental variables and individual vulnerabilities to better understand the complex emotional interchange between mother and infant.

Research Highlights

  • The Problem: Researchers seek to determine if behavioral and developmental patterns resulting from social deprivation and maternal separation in rhesus monkeys are similar enough to human infant patterns to serve as a valid experimental model. 

  • The Method: The study synthesizes data from laboratory experiments using surrogate mothers (wire and cloth), isolation chambers, and playpen tests with rhesus monkeys alongside clinical observations of institutionalized human infants. 

  • Quantitative Finding: Newborn rhesus monkeys show strong visual curiosity at 3 days of age; manipulatory exploration begins at 20 days; a fear-response system develops between 20 and 40 days; and responsiveness to the mother's face increases at approximately 45 days, similar to human infants at 2 to 3 months. 

  • Qualitative Finding: Socially deprived monkeys and humans both display abnormal behaviors such as infantile autism, aggression, and impaired sexual or maternal responsiveness; monkeys utilize cloth surrogates as a psychological "base of operations" for exploration; maternal separation in both species triggers a characteristic sequence of protest, followed by despair or apathy. 

  • Finding: The presence of a "mother-figure" provides the necessary security to release innate curiosity and exploration systems, and early social stimulation is a critical variable in preventing permanent intellectual and personality disturbances in both rhesus monkeys and human infants. 

Publication Date

5-1973

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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