Autonomy in Action: Linking the Act of Looking to Memory Formation in Infancy via Dynamic Neural Fields

Looking is a fundamental exploratory behavior by which infants acquire knowledge about the world. In theories of infant habituation, however, looking as an exploratory behavior has been deemphasized relative to the reliable nature with which looking indexes active cognitive processing. We present a new theory that connects looking to the dynamics of memory formation and formally implement this theory in a Dynamic Neural Field model that learns autonomously as it actively looks and looks away from a stimulus. We situate this model in a habituation task and illustrate the mechanisms by which looking, encoding, working memory formation, and long‐term memory formation give rise to habituation across multiple stimulus and task contexts. We also illustrate how the act of looking and the temporal dynamics of learning affect each other. Finally, we test a new hypothesis about the sources of developmental differences in looking.     

The impact of breastfeeding on mothers' attentional sensitivity towards infant distress

Background

Maternal response towards infant distress has an important impact on infant development. In animals it is established that lactation and pup suckling plays an important role in maintaining maternal responses. Previous research suggests that breastfeeding is associated with sensitive maternal responses in human mothers. However, this may be because women who are more sensitive to their infant choose to breastfeed. The current study investigated the attentional sensitivity towards infant distress in women who went on to breast or formula feed during pregnancy as well as after birth. We hypothesised that differences in breast and formula feeding mothers would only emerge after birth once feeding had commenced.

Method

Women were recruited during pregnancy through community midwives as part of a longitudinal study. 51 women were seen during late pregnancy and between 3 and 6 months after birth (27 were breast and 24 were formula feeding). Sensitivity to infant distress was measured as the extent of women's attentional bias towards infant distress stimuli.

Results

After birth, we found that our index of attentional bias towards infant distress was 37 ms (0.5 S.D.s) (CI; 6-69, p = 0.021) higher in breastfeeding compared to formula feeding mothers. However, mothers who went on to breastfeed did not show greater attentional bias towards infant distress already during late pregnancy.

Conclusions

Our results suggest that the act of breastfeeding may influence mothers’ attentional sensitivity towards infant distress. Previous research suggests breastfeeding is indicative of sensitive parenting. The current findings may suggest a mechanism by which breastfeeding and/or associated infant interaction could contribute to this sensitivity.     

Anticipatory reaching of seven- to eleven-month-old infants in occlusion situations

The present study examined 7- to 11-month-old infants’ anticipatory and reactive reaching for temporarily occluded objects. Infants were presented with laterally approaching objects that moved at different velocities (10, 20, and 40 cm/s) in different occlusion situations (no-, 20 cm-, and 40 cm-occlusion), resulting in occlusion durations ranging between 0 and 4 s. Results show that except for object velocity and occlusion distance, occlusion duration was a critical constraint for infants’ reaching behaviors. We found that the older infants reached more often, but that an increase in occlusion duration resulted in a decline in reaching frequency that was similar across age groups. Anticipatory reaching declined with increasing occlusion duration, but the adverse effects for longer occlusion durations diminished with age. It is concluded that with increasing age infants are able to retain and use information to guide reaching movements over longer periods of non-visibility, providing support for the graded representation hypothesis (Jonsson &; von Hofsten, 2003) and the two-visual systems model (Milner &; Goodale, 1995).     

Rapid acquisition of phonological alternations by infants

We explore whether infants can learn novel phonological alternations on the basis of distributional information. In Experiment 1, two groups of 12-month-old infants were familiarized with artificial languages whose distributional properties exhibited either stop or fricative voicing alternations. At test, infants in the two exposure groups had different preferences for novel sequences involving voiced and voiceless stops and fricatives, suggesting that each group had internalized a different familiarization alternation. In Experiment 2, 8.5-month-olds exhibited the same patterns of preference. In Experiments 3 and 4, we investigated whether infants' preferences were driven solely by preferences for sequences of high transitional probability. Although 8.5-month-olds in Experiment 3 were sensitive to the relative probabilities of sequences in the familiarization stimuli, only 12-month-olds in Experiment 4 showed evidence of having grouped alternating segments into a single functional category. Taken together, these results suggest a developmental trajectory for the acquisition of phonological alternations using distributional cues in the input.     

Newborn temperament and Sudden Infant Death Syndrome: A comparison of victims and their cotwins

Temperament assessed in the newborn period was compared for four twin infants who subsequently died of Sudden Infant Death Syndrome (SIDS) and their surviving cotwins. The assessment focused on irritability, resistance to soothing, reactivity, reinforcement value, activity while awake, and activity during sleep. No differences were observed between cotwins on a combined irritability rating. SIDS victims, however, were less irritable than their siblings in response to aversive stimuli. When irritable, the SIDS infants were more difficult to soothe than their cotwins. While awake, SIDS infants were less active than their cotwins, but during sleep, no activity differences were observed. The SIDS infants were more reactive to orienting stimuli, and neither group was found to be more or less rewarding to the examiner. It was concluded that this study has helped to define behavioral variables that might be characteristic of infants whose subsequent deaths are attributed to SIDS.     

Contribution of facial and vocal cues in the still-face response of 4-month-old infants

The contribution of contingent facial and vocal information in the still-face effect was investigated. Four-month-old infants either saw and heard their mother, only saw their mother, or only heard their mother interacting with them. These interaction periods were followed by the cessation of the mother's interactive face and/or voice. Only infants who observed their mother's face become still and neutral, showed a still-face effect by decreasing their visual attention and positive affect. The findings provide further support that the mother's interactive voice does not contribute to the still-face effect. The developing sensitivity to vocal information in dyadic and triadic contexts is discussed.     

Infant directed speech and the development of speech perception: Enhancing development or an unintended consequence?

Infant directed speech (IDS) is a speech register characterized by simpler sentences, a slower rate, and more variable prosody. Recent work has implicated it in more subtle aspects of language development. Kuhl et al. (1997) demonstrated that segmental cues for vowels are affected by IDS in a way that may enhance development: the average locations of the extreme “point” vowels (/a/, /i/ and /u/) are further apart in acoustic space. If infants learn speech categories, in part, from the statistical distributions of such cues, these changes may specifically enhance speech category learning. We revisited this by asking (1) if these findings extend to a new cue (Voice Onset Time, a cue for voicing); (2) whether they extend to the interior vowels which are much harder to learn and/or discriminate; and (3) whether these changes may be an unintended phonetic consequence of factors like speaking rate or prosodic changes associated with IDS. Eighteen caregivers were recorded reading a picture book including minimal pairs for voicing (e.g., beach/peach) and a variety of vowels to either an adult or their infant. Acoustic measurements suggested that VOT was different in IDS, but not in a way that necessarily supports better development, and that these changes are almost entirely due to slower rate of speech of IDS. Measurements of the vowel suggested that in addition to changes in the mean, there was also an increase in variance, and statistical modeling suggests that this may counteract the benefit of any expansion of the vowel space. As a whole this suggests that changes in segmental cues associated with IDS may be an unintended by-product of the slower rate of speech and different prosodic structure, and do not necessarily derive from a motivation to enhance development.     

Possibilities and limits of mind-reading: A neurophilosophical perspective

Access to other minds once presupposed other individuals’ expressions and narrations. Today, several methods have been developed which can measure brain states relevant for assessments of mental states without 1st person overt external behavior or speech. Functional magnetic resonance imaging and trace conditioning are used clinically to identify patterns of activity in the brain that suggest the presence of consciousness in people suffering from severe consciousness disorders and methods to communicate cerebrally with patients who are motorically unable to communicate. The techniques are also used non-clinically to access subjective awareness in adults and infants. In this article we inspect technical and theoretical limits on brain–machine interface access to other minds. We argue that these techniques hold promises of important medical breakthroughs, open up new vistas of communication, and of understanding the infant mind. Yet they also give rise to ethical concerns, notably misuse as a consequence of hypes and misinterpretations.