Do Infants See the World Differently? A Comparison Between Perception in Infants and Adulthood

According to Epstein, Dember, and West (2018), the perception in adults is a process by which sensory stimulations are translated into related experiences. The percept or the experience is a joint product of the process itself, as well as the stimulus. Since perception is in the scientific enterprise, it has developed as a part of the broader discipline of psychology. Even so, the perception in infants and adults is different. Infant perception, which can be considered as a process through which a human infant (aged between 0 and 12 months) responds to and gains awareness of external stimuli (Kim & Johnson, 2017). Kim and Johnson (2017) articulate that infants at birth have functional sensory systems as vision is considerably organized, and olfaction, audition, and touch are reasonably mature. Even so, infants still lack perceptual knowledge, which as Kim and Johnson (2017) highlight, must be gained via experience with the world around them. As the senses of the infants develop and mature, they begin coordinating information that is obtained via multiple sensory modalities. As Kim and Johnson (2017) report, the process of coordination is referred to as intermodal perception, which usually begins and improves across the development if the infant. As such, this implies that the perception of infants and adults is different. This didactic essay will discuss the fundamental basics of sensation and perception in adults and infants. It will address infant sensation and perception and how it differs to adults and how it is similar. Furthermore, it will demonstrate underlying neural mechanisms involved in infant perception. Also, this essay will seek to explore the differences in color and acoustic perception, perceptual differences in vision and pain sensation in infants versus adults.

The most basic visual functions are operational but immature at birth. According to a study conducted by Johnson (2010), the visual world of adults is different compared to that of infants. That of adults is consistent with objects at various distances and partly occluding each other, stable and substantial across space and time. However, the infants visual world is different in that it is often fragmented and unstable, which does not include coherent objects but only surfaces that move unpredictably (Johnson, 2010). However, the visual acuity and capability of distinguishing fine details is approximated at 20/400 for most of the newly born infants. The acuity develops rapidly within the first few months (Kim & Johnson, 2017). On the other hand, contrast sensitivity, which is the capability of detecting luminance differences between two adjacent objects is also reduced in newborns in comparison to that of adults. However, this develops as the infants gain visual experience. Kim and Johnson (2017) also articulate that color vision usually advances and nears perceptual ability of adults in a period of four to six months.

Also, the perception of motion, being an essential part of persons visual interpretation of the environment. The response of infants to fast and slow motion velocities differ in accordance with age and the type of motion that is observed. Besides, the motion of the infants is also significant as it contributes towards motion perception. Even with the various types of movement (lateral, vertical, rotation, and away and towards observers) and their complexities, all kinds of motion perception are deemed to develop in about six months in healthy infants (Kim & Johnson, 2017). On the other hand, depth perception gradually grows in the first several months. At first, the infant becomes sensitive to kinematic motion at about two months, where the newborn can perceive being moved from one surface about another. At a period of four months, infants can be able to perceive depth, and more particularly stereoscopic depth, which help provide information about the distances of objects in near space as a function of their relative position horizontally within the visual field (Kim & Johnson, 2017). However, at seven months, infants are capable of perceiving depth in a flat and two-dimensional pictures.

Infants usually develop object perception, and more specifically, recognizing boundaries at a period of three to five months. According to a study by Johnson, Slemmer, and Amso (2004), the fundamental question of perceptual development is mainly concerned of how infants come to perceive objects that are partly hidden objects as unified in a spatial gap that an occlude imposes. Johnson et al., (2004) investigated the inputs of the process by recording eye movements in three-month-old infants as they were involved in a standard object unity task. The researchers found systematic differences in the scanning patterns between infants who had post-habituation preferences (indicative of unity perception) versus infants who did not perceive unity. As such, the researchers pointed out that perceivers, relative to non-perceivers scanned more reliably within the vicinity of visible rod parts and even scanned more frequently across the range of the rod motion. As such, the results revealed that emerging object concepts are closely tied to the available visual information within the environment, as well as the process of picking up the information (Johnson et al., 2004).

Besides, object perception is usually complicated and entails multiple information-processing tasks, including perceiving shapes, substances of objects, sizes, and boundaries (Kim & Johnson, 2017). However, infants recognizing objects alone does not necessarily reveal the complete shape or size of the object as opposed to adults. However, despite the limited visual experience, infants have some sense of both shape and size constancy. Additionally, infants can perceive faces as they can recognize faces that are familiar despite their variations in both perspective and expression (Kim & Johnson, 2017). They can also discriminate faces based on their gender as most of the infants show preferences for females; however, newborns who have been handled by males prefer males to females. The infants can perceive differ5ent facial expressions by the third month and by seven months they can discriminate an extensive range of facial expressions, such as anger, happiness, fear, sadness, and surprise, but it is unlikely that they can comprehend the content of this range of emotions.

Further, infants have auditory perception. However, perception of low frequencies is poor in young infants in comparison to high frequencies. According to a study conducted by Lewkowicz (1996), which entailed investigating infants and adults perception of auditory-visual temporal synchrony, it was established that the magnitude of auditory-visual temporal asynchrony threshold was different among the two groups of participants. The detection threshold for asynchrony of sound that precedes a visible event was 350 ms for infants and 65 ms for adults while that created by the sound that follows a visible event was 450 m for infants and 112 ms for adults. The infants did not respond to those asynchronies exceeding intervals that yielded reliable discrimination, and thus, infants auditory-visual unity is often guided by synchrony asynchronies window, which becomes narrower as the infant develops.

Essentially, low-frequency discrimination does not mature until the child in ten years old, but the discrimination of high frequencies is usually superior among infants compared to high-frequency discrimination among adults (Kim & Johnson, 2017). Even though they do not have the capability of discriminating low frequencies, the infants absolute threshold improves over time in their infancy and reaches adult levels by the moment they reach puberty, and the higher the frequencies, the earlier adult levels are attained. Besides, as early as seven months, the infants can be able to discriminate between sounds of different timbres that are characterized by the same pitch, but the adult levels of competence at distinguishing various tones of the similar pitch are not reached until into childhood (Kim & Johnson, 2017). Once different types of auditory information are received, infants need to organize it perceptually in various meaningful elements. The process of grouping among infants is partly functional but is more effortlessly disrupted in children in comparison to adults. However, part of the process is ignoring irrelevant sounds while attending to the relevant sound source. Nevertheless, another difference that was noted is that infants, as opposed to adults, often act as if they are not sure about what sounds to disregard.

Additionally, in speech perception, infants often appear to have difficulty in segregating speech from variant competing sounds (Kim & Johnson, 2017). For this reason, when interacting with the infants, often, caregivers compensate this difficulty by making an acoustic adjustment, for example, making an infant-directed speech. Infants also exhibit preferences for speech sounds over non-speech sounds, and they do not always prefer speech as they are attentive to other forms of communication, for example, sign language (Kim & Johnson, 2017). Lastly, infants have intermodal perception. While adults experience the world via the integration of sensory impressions, infants can coordinate the information they perceive via different senses (Kim & Johnson, 2017). They can detect arbitrary audio-visual relations presented to them in the process of familiarization. Even so, intermodal relations are more specific than arbitrary, and thus, adults are different because their phenome perception is strongly influenced by watching faces, in what is known as the McGurk effect. In essence, when adults hear a specific syllable while looking at a face that produces the syllable, they perceive the sound that is associated with the lip movements instead of the actual phoneme they heard. In comparison, infants, and more specifically, five-year-olds are vulnerable to this effect.

A study in 2007, showed a difference in categorical perception of colour between adults and infants. It found that perception of colour is lateralized to the right hemisphere in infants and to the left hemisphere in adults. This suggests there are neurological differences between infants and adult perception. (Franklin et al., 2008). Categorical Perception (CP) of color, as Franklin et al. (2008) and highlight, is usually shown when two colors that belong to variant color categories (judgments that are between-category), are discriminated in a fast manner or in a greater accuracy compared to two colors that belong to the same color category (judgements that are within-category), even when within- and between-category chromatic sizes of separation are equated. The effect is usually found in children and toddlers, adults, and infants. Since the significance of language on the effect is often debated, various hypotheses have been formulated. One of them is that online language usage is attributed to CP as comparing various stimuli labels helps discrimination for between-category pairs and hinders within-category pair discrimination. As such, supporting the hypotheses demands that for adults, CP is found only when the category boundary is marked in the participants language, and verbal interference with therefore eliminate CP, but not visual interference. Besides, Franklin, Clifford, Williamson, and Davies (2005a) also posited that color CP usually occurs pre-linguistically in infants and toddlers with no color language.

To support the hypothesis that for adults, CP is found only when the category boundary is marked in the...