Single Review on past events

As a guest of the Zukunftskolleg working group “Foundation of Semantics” Paul Pietroski was invited to give a talk at the Jour Fixe. He is Professor of Philosophy and Linguistics at the University of Maryland. His main research interests lie at the intersection of these fields. Recently, his work has focused on how grammatical structure is related to logical form, how meaning is related to truth, and how human concepts are related to linguistic understanding. His research group relies on insights from the study of vision in their experimental studies of linguistic meaning.
In his lecture titled “Semantic Framing: The Meaning of 'Most'” Paul Pietroski presented a case study in which the meaning of most was investigated. 12 naive adults were given 360 trials each; on each trial were 5-17 dots of two or more different colors (e.g. blue and yellow). The trials varied by ratio (from 1:2 to 9:10) and type. Each “dot scene” was displayed for 200ms. The target sentence was: Are most of the dots yellow? The participants could answer ‘yes’ or ‘no’ by pressing buttons on a keyboard and the correct answers were randomized.

Paul Pietroski and his collaborators wanted to find out how the interrogative sentence is understood, and what conditions make the interrogative easy/hard to answer? They expected that their analyses might provide clues about how the sentence is understood (given decent accounts of the information available to human beings in those conditions).

They applied a model of “Approximate Number System” (key feature: ratio-dependence of discriminability) which proved that distinguishing 8 dots from 4 (or 16 from 8) is easier than distinguishing 10 dots from 8 (or 20 from 10). Correlatively, as the number of dots rises, “acuity” for estimating of cardinality decreases, but still in a ratio-dependent way, with wider “normal spreads” centered on right answers.

Further they discovered that the performance of the participants was better if the question was not posed with most. Framing the question with most has effects that are expected if the question is understood in terms of cardinality comparison. It also has effects that are expected if the question is understood in terms of cardinality subtraction.

In scenes with two colors, e.g. blue and red, the non-blues can be identified with the reds. The visual system “selects” the dots, the blue dots, and the red dots; these 3 sets are estimated for cardinality, but adding colors makes it harder (and with 5 colors, impossible) to obtain a cardinality estimate for each color.

Based on these findings Paul Pietroski concludes that the way you ask the question is more important than the number of dots – as people seem to hate counting –, which means that semantic framing has an effect on the meaning of words such as most.

More information about Paul Pietroski: http://www.philosophy.umd.edu/people/pietroski