Topic 9 - Differential Psychology and Comparative Psychology

Differential psychology

Variations in intelligence, personality and aptitudes between people. Psychological Tests.

Comparative psychology

similarities and differences in animal and human behaviour. Evolutionary bases

Francis Galton: the study of individual differences

Francis Galton pioneered the study of individual differences by applying evolutionary ideas to psychology, founding differential psychology and psychometrics, and arguing that mental traits like "genius" are largely heritable, measurable, and vary among individuals.

Alfred Binet (1857–1911) the first intelligence tests

A French psychologist, worked with Théodore Simon to create the first scale of child intelligence (1905). 

Commissioned by the French Ministry of Education, this scale sought to identify children with learning difficulties in order to offer them specific support.

Their goal was practical: to adapt teaching to the needs of each child. 

Example: A child had to repeat series of digits, define words, and solve simple problems; if they failed at tasks appropriate for their age, educational support was recommended. 

Comparative psychology: the study of animal behaviour - Charles Darwin

Darwin (1809–1882), an English naturalist, formulated the theory of evolution by natural selection. In The Descent of Man (1871), he applied his evolutionary framework to the study of mental faculties, arguing that the differences between humans and animals are one of degree, not of kind.

This perspective opened the door to comparative psychology: The differences between the mental faculties of man and higher animals, however great they may be, are of degree and not of kind. Animals experience pleasure and pain, happiness and misery, and they also possess curiosity, imitation, attention, and memory. 

Darwin established the continuity between humans and animals, the foundation of comparative psychology.

Karl von Frisch and social animal behavior Von Frisch (1886–1982), 

An Austrian zoologist, was awarded the Nobel Prize in 1973 for his studies on bee communication. 

He discovered the "bee dance" as a form of symbolic language, which showed that even insects have complex systems of communication and learning: Bees perform a dance in a circle or straight line that indicates to their companions the direction and distance of the food source. The dance is, therefore, a language of extraordinary precision. von Frisch, Von Frisch showed that animal behavior can be studied experimentally, revealing communication and orientation abilities.

Conclusion 

Differential and comparative psychology consolidated two fundamental aspects of the discipline. On the one hand, the study of individual differences paved the way for psychometrics and psychological assessment, with pioneering contributions from Galton and Binet. On the other hand, comparative psychology established the continuity between humans and animals, showing that psychological processes have an evolutionary basis. Both currents, although partly marginal compared to the major schools, have had a lasting impact: the assessment of intelligence and personality is now a central practice in education, clinical settings, and personnel selection; and comparative psychology evolved into ethology and animal cognition, contributing to neuroscience and evolutionary psychology.