Knowledge of Objects
Lecturer: Stephen A. Butterfill
Slides
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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] …
- Either Wy believes that there’s a spider behind the book, or she does not.
- Either Wy can act for the reason that there is, or seems to be, a spider behind the book, or else she cannot.
- 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.