An Experimental Paradigm for Measuring the Effects of Ageing on Sentence Processing

Summary

Here, we present a protocol to examine the age-related decline in sentence processing using a maze task that allowed us to localize the processing difficulty at each word of the sentences during reading.

Abstract

Previous studies have found that older adults have greater difficulties in processing syntactically complex sentences than younger adults. However, the exact regions where the difficulties arise have not been fully identified. In this study, a maze task was implemented to investigate how older adults and younger adults differentially processed two types of sentences with different levels of syntactic complexity, namely subject relative clauses and object relative clauses. Participants were asked to choose between two alternatives at each segment of the sentences. The task required participants to engage in a strictly incremental mode of processing. The reading times for each segment were recorded, allowing the quantification of the difficulty of sentence reading. The task allowed us to identify the exact locations of the processing difficulty and thus facilitate a more accurate assessment of the age-related decline in sentence processing. The results indicate that the effect of ageing was found mainly at the head nouns, but not at other regions of the sentences, a finding which suggests that the maze task is an effective method to identify the exact location of the ageing effect on sentence processing. The implications of this experimental paradigm for investigating the effect of ageing on sentence processing are discussed.

Introduction

Sentence processing is an essential process for human beings to comprehend sentences in natural languages. It requires integrating incoming words into the existing sentential structures and establishes relationships between words in the sentence in a way which conforms to the grammatical constraints. As sentence processing is a resource-demanding process, older adults tend to encounter difficulties due to the age-related decline in working memory. Previous studies have found that older adults have great difficulties in comprehending and processing sentences with complex syntactic structures such as relative clauses (RCs): "The reporter whom the senator attacked ad....

Protocol

The experiment was approved by the Ethics Committee of Beijing Foreign Studies University and it complied with the guideline for experiments with human subjects. All participants in the experiment provided written informed consent.

1. Stimuli Construction

1. Construct experimental stimuli on the basis of the specific experimental questions. This protocol is intended to explore the effect of ageing on online sentence processing during reading, and as such, the visual stimuli used in the experiment are two types of RCs, namely SRCs and ORCs, which are the structures most frequently used in the studies of sentence processing by older ....

Results

This study is intended to examine the effect of ageing on online sentence processing using a maze task. The RTs for each segment in the sentences are used to indicate the processing difficulty. In this study, we explored how a group of older adults (M_age = 65.2, SD = 3.04, Range = 59 -74) and younger adults (M_age = 19.1, SD = 1.04, Range = 18-23) differentially processed Mandarin SRCs and ORCs. The two age groups were matched in education (M_old = 12.8, SD .......

Discussion

In this study, a maze task was used to find the exact location for the effect of ageing on sentence processing. The study examined how older adults and younger adults differentially processed Chinese SRCs and ORCs. In the task, participants were instructed to read a sentence by choosing between two alternatives, only one of which was the grammatical continuation of the sentence. They were required to make the choice as quickly and as accurately as possible. If participants chose the correct alternatives in the sequence, .......

Materials

Name	Company	Catalog Number	Comments
Computers	N/A	N/A	Used to present stimuli and record subjects' responses.
E-prime	PST	2.0.8.22	Stimulus presentation software
The Digital Working Memory Span Test	N/A	N/A	Used to assess subjects' working memory span. From Wechsler (1987).
The Global Deterioration Scale (GDS)	N/A	N/A	Used to assess subjects' general cognitive status. From Reisberg, Ferris, de Leon and Crook (1988)