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Origins of Mind

Knowledge of Objects

Lecturer: Stephen A. Butterfill

Slides

Notes

In this lecture we will consider evidence on infants’ abilities to track physical objects, and on the limits of these abilities.

Preview

When do humans first come to know facts about the locations of objects they are not perceiving? (This ability is sometimes called object permanence.)

The answer depends on how we measure their abilities:

look (habituation): by 4 months of age or earlier (Baillargeon, 1987).

look: by around 2.5 months of age or earlier (Aguiar & Baillargeon, 1999, p. Experiment 2)

search: not until after 7 months of age (Shinskey & Munakata, 2001)

Could the discrepancy be entirely due to infants’ difficulties performing actions? Probably not: ‘action demands are not the only cause of failures on occlusion tasks’ (Shinskey, 2012, p. \ 291).

In short,

‘violation-of-expectation experiments, using looking-time measures, suggested that infants have object permanence in occlusion conditions; but simplified-search studies confirm that infants fail to reach towards occluded objects, suggesting that infants do not have object permanence in occlusion conditions. This discrepancy, however, is only the tip of the iceberg. Results of studies attempting to measure infants’ cognitive abilities using reaching measures often contradict results gained while using looking-time measures’ (Charles & Rivera, 2009, p. \ 994).

Uncomplicated Account of Minds and Actions

For any given proposition [There’s a spider behind the book] and any given human [Wy] …

  1. Either Wy believes that there’s a spider behind the book, or she does not.
  2. Either Wy can act for the reason that there is, or seems to be, a spider behind the book, or else she cannot.
  3. The first alternatives of (1) and (2) are either both true or both false.

Discoveries about how abilities to track unperceived objects develop form a pattern sometimes described as paradoxical. This is because those discoveries conflict with the Uncomplicated Account.

Glossary

habituation : Habituation is used to test hypotheses about which events are interestingly different to an infant. In a habituation experiment, infants are shown an event repeatedly until it no longer holds their interest, as measured by how long they look at it. The infants are then divided into two (or more) groups and each group is shown a new event. How much longer do they look at the new event than at the most recent presentation of the old event? This difference in looking times indicates dishabituation, or the reawakening of interest. Given the assumption that greater dishabituation indicates that the old and new events are more interestingly different to the infant, evidence from patterns of dishabituation can sometimes support conclusions about patterns in how similar and different events are to infants.
object permanence : the ability to track objects while briefly unperceived.

References

Aguiar, A., & Baillargeon, R. (1999). 2.5-month-old infants’ reasoning about when objects should and should not be occluded. Cognitive Psychology, 39, 116–157.
Baillargeon, R. (1987). Object permanence in 3.5-and 4.5-month-old infants. Developmental Psychology, 23(5), 655–664.
Charles, E. P., & Rivera, S. M. (2009). Object permanence and method of disappearance: Looking measures further contradict reaching measures. Developmental Science, 12(6), 991–1006. https://doi.org/10.1111/j.1467-7687.2009.00844.x
Shinskey, J. L. (2012). Disappearing décalage: Object search in light and dark at 6 months. Infancy, 17(3), 272–294. https://doi.org/10.1111/j.1532-7078.2011.00078.x
Shinskey, J. L., & Munakata, Y. (2001). Detecting transparent barriers: Clear evidence against the means-end deficit account of search failures. Infancy, 2(3), 395–404.