Perception and Cognition in Infancy Flashcards
The existence of visual preferences in infancy
Fantz (1961, 1966)
The existence of visual preferences in infancy provides a useful index of infant’s perceptual abilities as well as of their attentional skills. The existence of a preference implies that the infant can distinguish between different entities.
The ‘visual preference’ technique was first used by Fantz (1961, 1966), who studied simple perception of forms in a ‘looking chamber’ which enabled the tracking of infant gaze. However, a ‘no preference’ result in the visual preference paradigm is difficult to interpret. A way of finding out whether infants can in fact distinguish two equally-preferred visual stimuli is to use habituation. The infant is repeatedly shown an object (O1) until looking time falls off. A new object is then shown (O2). If the infant shows renewed looking, discrimination between O1 and O2 is assumed. Habituation is assumed to provide a way into infants’ conceptual (cognitive) representations.
Habituation
The visual preference+
By combining habituation with an action, such as sucking, infants can be enabled deliberately to choose between stimuli. In one famous “sucking” experiment (De Casper & Fifer, 1980), newborn babies were given a dummy to suck.
First, their natural or “baseline” sucking rate was measured.
Next, the infants were played a tape recording of their mother reading a story. Each time their suck rate increased above baseline, the tape would play. Each time the suck rate dropped below baseline, a strange female voice would be heard instead, reading the same story. The infants rapidly learned to suck fast to hear their mother’s voice. The following day, the experimenters reversed the contingency. Now slower sucking was required to hear their mother’s voice – and the babies reversed their suck rates.
Sucking can also be used to measure cross-modal understanding.
Sucking can also be used to measure cross-modal understanding. Meltzoff and Borton (1979) gave one-month-old infants one of two dummies to suck that had different textures. The surface of one of the dummies was smooth, whereas the other had a nubbled surface. The infants were prevented from seeing the dummy when it was placed into their mouths, and so in the first phase of the experiment their experience of the dummy was purely tactile. In the second phase of the experiment, the infants were shown enlarged pictures of both dummies, and the experimenters measured which visual stimulus the infants preferred to look at. They found that the majority of the babies preferred to look at the dummy that they had just been sucking.
Visual preferences->Habituation -> Suckling behaviour ->Cross-modal understanding
how cognitive concepts might arise from perceptual information?
First, we return to Piaget’s theory, focussing on the sensory-motor period (0-2yrs). Piaget claimed that cognitive development begins in this period through the physical actions the infant performs on objects in the world.
Immediate sensation of their actions is the infant’s only means of understanding. The very first actions are determined by innate sensori-motor schemas (e.g sucking, grasping). During infancy, these knowledge schemas become gradually elaborated and restructured through the processes of accommodation and assimilation (see lecture 1).
Piaget posited that initially, babies draw no distinction between themselves and the external world (infantile egocentrism). Through acting upon the world, they gradually construct their understanding of a world separate from themselves.
The task of this stage is the development of a distinction between self and the world, a distinction which comes through the development of representation– thought about objects no longer present or available to immediate perception (re-presentation in the mind).
The end of the sensori- motor period children start to produce drawings, language pretend play, imitation of others (even after some delay – memory). All of these are indicative of representational thought.
“object concept” or “object permanence”
Piaget called thought about objects that are no longer present or available to immediate perception the “object concept” or “object permanence” and argued that changes in infants search behaviours across the sensori-motor period demonstrates that object permanence developed gradually.
Piaget noted that sensori-motor infants do not search for fully occluded objects until some time after they are physically capable of doing so. They also make the “A not-B error” at 8-10 months – after retrieving an object from one location A several times, they fail to search when the object is hidden in a new location B, and instead return to the first, now empty, location A. Piaget’s interpretation of the A not-B error was that the infant is still unable to represent objects independently of themselves.
-Wasserman -object permanence 5 months old
Piaget has been criticised for underestimating infant competence
Piaget has been criticised for underestimating infant competence, because he simply observed their natural search behaviours. Others have argued that even very young infants may be aware that occluded objects continue to exist but are unable to co-ordinate search when objects are hidden.
Violation of expectation
A number of studies have used an alternative measure to assess the conceptual abilities of very young infants, known as ‘violation of expectation’. The logic of these studies is that if babies understand certain concepts, they will look surprised (i.e. dishabituate) if an event occurs which violates that understanding. The experimental methods set up conditions that result in physically ‘impossible’ events. If infants look longer at the impossible events compared to a control condition, this implies an ability to represent the causal structure of these relations (work of Baillargeon). Claims have been made that babies of 3.5 months understand object permanence, by using these procedures.
Baillargeon, Spelke and Wasserman (1985)
In one famous study, Baillargeon, Spelke and Wasserman (1985) habituated 5-month old babies to a display in which a screen continually rotated through 180’ towards and away from the baby, like a drawbridge. Following habituation, a box was placed in the path of the screen. As the screen began its 180’ rotation, it gradually occluded the box. When it reached 90’, the entire box was hidden from view. For babies who were shown a ‘possible event’, the screen continued to rotate until it had passed through 120’, at which point it came to rest, apparently having made contact with the box. For babies who were shown an ‘impossible event’, the screen continued to rotate until it had passed through the full 180’ rotation. The infants looked longer at the display when the screen passed through an apparently solid object. Baillargeon et al. argued that the babies had represented the box as continuing to exist, even when it was occluded by the screen, demonstrating that babies aged 5 months had an understanding of ‘object permanence’.
Crticism on Baillargeon
Baillargeon has used the violation of expectation (VoE) paradigm in many studies of infant cognition, to great effect.
However, her research enterprise has not been without criticism. Her critics are highly resistant to the notion that young infants engage in physical reasoning (e.g., Haith, 1998). As they point out, looking paradigms were developed to study sensory and perceptual questions, not cognitive questions. They argued that it is simply not possible to generate perceptually-identical but conceptually distinct stimuli for habituation paradigms (e.g., Sirois & Mareschal, 2002). Such critics argue that Baillargeon must be able to discount every possible perceptual interpretation of differences in looking time before proposing cognitive interpretations of infant looking behaviour. Bogartz, Shinskey and Speaker (1997) argued that simple perceptual mechanisms such as novelty, scanning and tracking may explain longer looking times by infants in some perceptual conditions versus others.
Haith-linger
Haith (1998) goes further, and suggests that infants may have lingering sensory information about objects that have been (for example) occluded from view, and that it is this lingering sensory information rather than a conceptual representation of the object that yields the changes that can be measured in looking behaviour. In other words, there is reduced sensory activity in the same perceptual systems that are active when a real object is present, even though the object has gone from the visual field. Haith suggests that this activity basically reflects degraded sensory representations.
cognitive neuroimaging
Kaufman-The toy train
To adjudicate between these views, we need new methods for studying infant cognition, and cognitive neuroimaging provides a range of possible methods.
A series of experiments with 6-month-old infants reported by Kaufman, Csibra and Johnson (2003) provides a nice example. Kaufman et al. used EEG imaging as a way of examining what infant’s “representations” of occluded objects were actually like.
The EEG (electroencephalogram) is a measure of brain electrical activation obtained by attaching sensitive electrodes to the scalp. Kaufman et al. recorded EEG when infants were watching different disappearance events involving a train and a tunnel, which were either expected or unexpected. The habituation event was a toy train going into a toy tunnel. The train was shown entering the tunnel, and then reversing back out again. Following habituation, the infants watched the train enter the tunnel, and then saw either (a) a hand lifting the tunnel to reveal the train (expected appearance event); (b) a hand lifting the tunnel to reveal no train (unexpected disappearance event); (c) the train leaving the tunnel and the visual field, and a hand subsequently lifting the tunnel to reveal the train (unexpected appearance event); or (d) the train leaving the tunnel and the visual field, and a hand subsequently lifting the tunnel to reveal no train (expected disappearance event).
Behaviourally, the infants looked significantly longer at the unexpected disappearance event compared to the expected disappearance event. The EEG data showed much higher activity when the train was occluded, on the right side of the brain only. In addition, when the tunnel was lifted to reveal no train (unexpected disappearance), there was sustained EEG activity which peaked around 500 ms after the lifting of the tunnel.
Kaufman et al. argued that this increased activity showed the brain attempting to maintain its representation of the train despite the competing visual evidence that the train was not under the tunnel. The finding that EEG activity increased appears to rule out explanations of infant looking based on degraded sensory inputs.
Finally, we consider evidence that young infants appear to possess a perceptual mechanism that assumes causality.
Leslie and Keeble
Finally, we consider evidence that young infants appear to possess a perceptual mechanism that assumes causality. This was shown by Leslie and Keeble (1987), who were interested in 6-month-old infants’ understanding of launching events. In a typical experiment, infants were shown one of two films. In one film, a red block moved towards a green block and then collided with it, directly setting the green block in motion. In the other film, the red block again moved towards a green block and made contact with it, but the green block only began to move after a delay of 0.5 seconds. While the first launching event gave an impression of causality to watching adults, the second did not.
Following habituation to one of the films, the infants were then shown the same film in reverse. Although the change in the spatio-temporal relations in the films was the same for both groups, the reversal of the ‘direct launching’ film resulted in a novel causal event (green launches red). The infants showed more dishabituation here (green launches red) than the infants in the delayed launching condition. Leslie (1994) argued that this showed recognition of a change in the mechanical (i.e., causal) roles of the two billiard balls. The ‘pusher’ was now the ‘pushed’. Recent adult studies using this paradigm suggest that low-level aspects of the visual system automatically foreground causal perceptual information for the brain – so this may also happen for infants (Moors et al., 2017)
