Pupillometric and behavioural evidence shows no differences between polyseme and homonym processing

Ambiguous words can have related meanings (polysemes, e.g., newspaper) or unrelated meanings (homonyms, e.g., bat). Here we examined the processing of both types of ambiguous words (as well as unambiguous words) in tasks of increasing level of semantic engagement. Four experiments were conducted in which the degree of semantic engagement of the task was manipulated: lexical decision task (Experiments 1 and 2), semantic categorization task (Experiment 3) and number-of-meanings task (Experiment 4). RTs and pupillary response were recorded. To our knowledge, pupillary response had never been used before to study ambiguous words processing in isolation. Results showed faster RTs for ambiguous words with respect to unambiguous words in LDT, and larger pupil dilation was observed for ambiguous words in comparison to unambiguous ones in number-of-meanings task. However, differences between polysemes and homonyms were not observed in any task. These results provide no evidence that polysemes and homonyms are processed differently