An Eye-movement Study On Cognitive Mechanisms Of Predictive Processing In Chinese Reading

This paper,with three studies,explored the cognitive mechanism of word predictive processing in Chinese reading from the perspective of top-down predictive processing and bottom-up parafoveal preview,and the impact of word predictability during natural text reading.The first study with two sentence reading experiments investigate whether word predictability effect is based on all-or-none word prediction or probabilistic semantic pre-activation from the perspective of top-down processing.Experiment 1 adopted a within-subject design of 2(context constraint: strong,weak)× 2(word predictability: high,low).The strong constraint context included high or low predictive target words while weak constraint context included only low predictive words.We compared whether there was significant difference when processing the same low predictable word in strong and low constraint contexts,i.e.,prediction error cost.The results showed that there was no significant difference on first pass reading measures when processing the same low predictable words in strong and weak constraint contexts,which demonstrated that the readers do not make top-down specific word prediction but pre-activate semantic information about upcoming content.Experiment 2 calculated the semantic similarity between low-predictable words and high-predictable words through latent semantic analysis method,manipulated semantic similarity with three-level(semantic similarity: high,medium,low).Word frequency,cloze probability,and strokes of low-predictable words were matched among the three levels.The results showed that as the semantic similarity between low-predictable words and high-predictable words decreased,the processing time for low-predictable words gradually increased,which illustrated the gradual characteristics of top-down predictive processing.Based on these two experiments,the first study concluded that readers made top-down predictions of future information based on probabilistic semantic pre-activation at normal reading speed.The second study used the boundary paradigm to investigate whether the word predictability effect is affected by the bottom-up parafovea preview processing.According to the Chinese Reading Model(CRM),word cognition depends on the interactive activation of word unit,character unit and visual unit.Therefore,the second study investigated how bottom-up parafoveal preview influences word predictability effect from the three perspectives of word,character,and visual preview.Experiment 3 adopted a completely within-subject design of 2(word predictability: high,low)× 2(preview condition: valid,invalid),experiment 4adopted 2(word predictability: high,low)× 3(preview condition: identical,transposed,substituted)within-subject design,experiment 5 used 2(word predictability: high,low)× 3(visual salience: high,medium,low)within-subject design.On the first pass reading measures,the experiment 3 and 4 was found significant word predictability effects on conditions of valid parafoveal word and character preview but not on control condition.This result showed that although the characters position information in the word was destroyed,the characters activation promoted the word activation through excitatory connection,which supported the eye movement control model of Chinese reading.The experiment 5 indicated that reducing the visual salience of the stimulus did not affect word predictability effect.In summary,the word predictability effect depends on bottom-up parafoveal preview processing.To improve the ecological validity of the research,the third study explored whether the word predictability based on the 3-gram language model affected natural text reading.We calculated occurrence probability of each word based on first two words,i.e.,word surprisal which is an objective indicator of word predictability.The word surprisal,frequency,and word length were used as independent variables,the first pass eye movement measures was used as the dependent variables.We analyzed whether the independent variables could explain the change of dependent variables.The result showed that word surprisal could explain the changes on the first pass reading eye movement measures,which indicated that word surprisal affected the early stage of word processing during natural text reading.The current research got following conclusions through three studies: first,under normal reading speed,the word predictability effect is based on top-down probabilistic semantic pre-activation;secondly,the word predictability effect relies on bottom-up parafoveal word or character preview,the characters activation promotes the word activation through excitatory connections,but reducing the visual salience of parafoveal stimulus while preserving the overall shape of the word does not interfere with the word predictability effect;finally,the probabilistic prediction also exits in natural text reading.