Researchers and theorists have long been interested in whether perceptual abilities are predominantly inborn or are a product of learning processes. This question forms part of the wider nature-nurture debate in psychology. Psychologists on the ‘nature’ side of the debate, referred to as ‘nativists’, argue that the abilities are innate and arise from inherited genetic factors, which predetermine their development along the process of maturation, whilst on the ‘nurture’ side, ’empiricists’ believe that abilities develop largely as a consequence of experience. In order to find sufficient support for either view, psychologists have investigated perceptual abilities in a number of different ways.
Their aim to resolve the debate has included studies on human infants, sensory restriction in non-human infants, perceptual readjustment, and cross-cultural differences. This essay considers evidence from studies conducted on human infants’ face, colour and pattern recognition, preference for complex and moving stimuli, and depth perception; it also aims to work towards a balanced conclusion in the nature-nurture debate.
The debate about the influence of heredity and environment in perception has a long history. The first nativists appeared in the 17th century, the earliest representatives were the French philosopher Decartes (1638, cited in Smith, Cowie and Blades, 2003) and the German philosopher Kant (1781, cited in Smith, Cowie and Blades, 2003). Both claimed that perceptual capacities, like space and depth perception, were inborn.
Later, in the early 20th century, Gestalt psychologists further supported this view by claiming that certain perceptual skills exist from the moment of birth because of the constructional features of the nervous system, and that these skills develop through maturation and interaction with the environment. Furthermore, gestalt psychologists emphasising the importance of instincts, which are inborn and responsible for starting the process of development in neonates. They also claimed that infants are born with the ability to order and arrange their perceptual world.
The empiricist view was developed by Locke (1690, cited in Smith, Cowie and Blades, 2003), who was greatly influenced by the early Greek philosophers, and was opposed to the Descartes’ rationalism. In contrary to Descartes, he put forward the idea of a ‘tabula rasa’ as the state in which humans enter the world. He asserted that perception is at first an unorganised and meaningless sensation, and that human knowledge and behaviour develops only through experience from sensation and unconditional reflexes that are inborn. Locke maintained that infants need to learn how to perceive; through repeated sensation, they form habits, which create judgement, which then modifies and enhances perception. Senses are seen as separate entities, which do not communicate with each other, because they are not yet linked.
Locke’s work greatly influenced James (1890, cited in Smith, Cowie and Blades, 2003), who maintained that what infants perceive about the world through their senses are nothing else-just a ‘blooming and buzzing confusion’. The ability to discriminate among sensations, like smell, shapes, colours, tastes, noises and voices, temperature, hunger, etc, is a result of a long learning process. The development of neuroscience and appearance of systematic experimentation techniques in the 1950s provided many contrary evidence, by which Locke’s theories were heavily criticised and mostly disproved.
Piaget represented a more balanced view between the two extremist schools. On the one hand, a closely related theory to empiricism was Piaget’s (1954, cited in Smith, Cowie and Blades, 2003) constructivism. On the other hand, Piaget’s view of infants’ perception borrowed some properties from the nativist theory; such as the idea of the inborn capabilities for assimilation, accommodation, equilibration and organisation of schemas.
The latter term refers to the inborn ability to co-ordinate existing schemas (cognitive structures) and blends them into more complex systems. He also further developed Locke’s philosophical theory of learning from reflexes, and that the knowledge of the world is not innate, but progressively learnt through experience by constantly exploring the environment. As neonates’ senses are not connected yet and hardly co-ordinated, he believed that objects do not become real entity until interaction between the senses happens by seeing, touching and tasting the objects. The results of constantly searching and experiencing the surrounding environment eventually lead to representation and objectification in the mind. Although the Piagetian stages of intellectual development are criticised as rigorous and not taking into consideration individual differences, it is still the most comprehensive theory of human development in psychology.
Until the 1950s, the empiricist view was the most influential in developmental psychology. Nativists initiated to study perceptual abilities in newborn infants, as the most direct way of assessing which perceptual abilities are inborn – assuming that the abilities are present at birth and have not been learnt in the womb. Although, this may sound obvious, researchers always faced difficulties when studying infant perception; for instance, infants could not tell them what they could perceive; they could easily become upset or distracted and then would not respond to the task; and the research method and process must always fulfil all the ethical requirements, therefore researchers were limited in the means.
To resolve these difficulties, a range of techniques have been developed in the last fifty years, which allow them to observe and infer what infants can and cannot perceive; and they are ‘the preference technique’, ‘habituation’ and ‘conditioning’. These technical resolutions helped Frantz conduct the first experiment on two day old infants.