Friday, 11 July 2014
In the second and more persuasive of their experiments, Jessica Wang and her colleagues presented 24 students with a carefully constructed box. The container was built such that a person could only identify the colour of the object inside by lifting up a cover; could only determine its temperature by putting their finger in a hole in the side; and could only judge the object's weight by lifting an attached string. The students were told that the box could contain one of eight identically shaped objects that varied according to their colour (green or white), their temperature (warm or cold) and weight (light or heavy).
Next, the participants were shown a succession of photographs of a man performing one of the aforementioned three actions, alongside a query relating to one of the three possible object characteristics. For example, after seeing the man lift the cover, the participant might be asked "Does he know if the object is heavy?" (correct answer: No). After seeing the man put his finger in the side of the box, the participant might be asked "Does he know if the object is warm?" (correct answer: Yes), and so on.
Wang and her team were interested in how long participants took to respond, and in particular the difference in response times for each action (i.e. looking, feeling, or lifting) when the correct answer was "Yes" versus "No". The students were particularly prone to hesitation when asked to judge whether the man could see the weight or temperature of the concealed object. In such cases, they nearly always arrived at the correct answer, but it took them a while to suppress their instinct to believe that sight could provide this information.
This is consistent with mistakes about vision made by children. It's as if we have an innate tendency, which persists into adulthood, to overestimate the information provided to us by our sense of sight. There was also a lesser tendency to overestimate the information provided to us by touch.
Wang and her team said past researchers have tended to interpret children's mistakes about vision in terms of their having an immature conceptual understanding of sight and the knowledge it provides. These new results suggest something else is going on. In adulthood, even when we fully understand at a conceptual level that it's not possible to see the weight or temperature of an object (because this information is not conveyed by its shape or other visual property), it takes us a moment to suppress the instinct to believe that vision does supply that information. I was disappointed that the researchers didn't speculate about why we have this tendency for over-confidence in vision.
"Further examinations into how our interactions with the world shape our reasoning about the knowledge that we gain from these interactions are necessary for a complete account of the cognitive characteristics of source of knowledge reasoning," they said.
Wang JJ, Diana Miletich D, Ramsey R, & Samson D (2014). Adults see vision to be more informative than it is. Quarterly journal of experimental psychology (2006), 1-14 PMID: 24853581
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.