Materials and procedure

A picture selection task was used to test the participants’ interpretations of pronouns in sentences testing subject and object parallelism. The experiment testing these two types of sentences was embedded in a larger experiment examining comprehension of pronouns and reflexives in simple transitive and ECM sentences, which was discussed in the previous chapter (see section 2.1.4.2. for a detailed description of the materials and the procedure). The full experiment consisted of 120 items in total, testing eight conditions of which four are discussed here.

The conditions that were relevant for this study were represented by 60 sentences in total, 15 per condition (see Appendix D for all test sentences). The relevant conditions consisted of pronouns in subject parallelism constructions, stressed and unstressed exemplified in (1) and (2), and pronouns in object parallelism constructions, stressed and unstressed exemplified in (8) and (9).

Similar to the set-up in Experiment 1 discussed in the previous chapter, in the present experiment each experimental item was accompanied by four pictures presented on two pages of A4 size (see Figures 3.1 and 3.2 for examples). The first conjunct was always shown in a single picture on the left page. There were three pictures on the right page. One of these pictures depicted the second conjunct of the sentence; the two other pictures were distractors. The unrelated distractor depicted the same actors but another action (the upper picture in Figures 3.1 and 3.2). In the Unstressed subject pronoun condition the related distractor depicted the interpretation where the pronoun referred to the DP functioning as the object of the first conjunct (Figure 3.1, bottom picture: the woman (object DP in the first conjunct) pinching the man). The correct picture is the middle picture, where the girl (subject DP in the first conjunct) is pinching the man. In the Stressed subject pronoun condition reference shifts so the correct picture is the bottom picture and the related distractor is the middle picture. In the case of the Unstressed

object pronoun condition the direct distractor depicted the interpretation

first conjunct (Figure 3.2, bottom picture: the man pinching the girl (subject DP in the first conjunct)). The correct picture is the middle picture, where the man is pinching the woman (object DP in the first conjunct). In the Stressed object pronoun condition, again reference is reversed, so the correct picture is the bottom picture and the direct distractor is the middle picture. The subject was asked to listen carefully to both parts of the sentence, look at the pictures and then point at the one that depicted the experimental sentence best.

There were two sessions in which the items were presented in blocks. The first block consisted of 15 sentences in the unstressed conditions mixed with fillers followed by 15 sentences in the stressed conditions mixed with fillers. The second block was the same as first. The reason for this block design was because the pre-test showed that mixing the stressed and unstressed conditions made the experiment too difficult for agrammatic patients. In addition, this type of design allows for an interpretation of the data as belonging to two different experiments, one testing parallelism and the other testing the effects of contrastive stress.

Figure 3.2

3.2.3 Results

The overall results of the agrammatic patients and the controls, as well as the individual data of aphasic patients are given in Table 3.1. The responses of the agrammatic patients were compared to the responses of the control group using a Mann Whitney U test. The agrammatic patients scored significantly worse on all conditions than the non-brain- damaged speakers (Unstressed subject pronoun, MWU: Z=-3.522, p<0.000;

Stressed subject pronoun, MWU: Z=-3.093, p<0.001; Unstressed object pronoun, MWU: Z=-2.506, p<0.011; Stressed object pronoun, MWU: Z=-

Table 3.1

Total and mean number of correct responses on pronouns in the four experimental conditions for aphasic speakers and the control group.

Broca’s (n=8) Unstressed subject pronoun Unstressed object pronoun Stressed subject pronoun Stressed object pronoun AD 14/15 8/15 6/15 10/15 AN 11/15 5/15 6/15 13/15 AK 13/15 6/15 6/15 9/15 JW 13/15 9/15 6/15 7/15 AL 10/15 7/15 8/15 8/15 IH 13/15 10/15 7/15 12/15 MJG* 7/15 11/15 4/15 7/15 GK* 11/15 13/15 12/15 2/15 Tot. % correct 76.6 57.5 45.8 56.7 Controls (n=15) 96.4 80.0 81.3 83.5

Note: * indicates two patients who exhibit the reverse response pattern from the rest of the group.

To test whether the agrammatic patients’ performance differed on the two crucial conditions (Unstressed subject pronoun and Unstressed object

pronoun), their correct responses on these conditions were compared

using a Wilcoxon Signed Ranks Test (Z=-1.684, p<0.09). No significant difference was found between their performances on these two conditions. The two stressed conditions also did not differ from each other (Wilcoxon: Z=-1.185, p<0.236). For the controls, on the other hand, a significant difference was found between the two unstressed conditions (Wilcoxon: Z=-2.944, p<0.03), indicating that their scores were significantly higher on the Unstressed subject pronoun condition than on the Unstressed object pronoun condition. There was no difference between the two stressed conditions (Wilcoxon: Z=-0.460, p<0.645).

Taking a closer look at the individual subject data of the agrammatic patients in Table 3.1 reveals an interesting pattern of errors for the unstressed conditions. There are two patients (MJG and GK) who commit more errors on the Unstressed object pronoun condition than on the Unstressed subject pronoun condition. The six other patients (AD, AN, AK, JW, AL and IH) all exhibit the reverse pattern, making significantly more errors on the Unstressed subject pronoun condition (Wilcoxon: Z=- 2.214, p<0.03), like the healthy controls. Because of the two patients whose response patterns deviate from those of the rest of the patients, the difference between the two experimental conditions is obscured and statistically insignificant.

Finally, I examined whether the agrammatic speakers performed differently from chance-level on the four conditions. The patients always

pointed at the direct distractor. Therefore, I assume that chance level performance on this task was 50%, although 33% would be the real chance level when randomly choosing between the three pictures. A binomial test showed that the patients’ scores on the Unstressed subject

pronoun condition did differ significantly from chance level (p=0.0001),

that is, the patients performed above chance on this condition. The scores on the Unstressed object pronoun (p=0.06), Stressed object pronoun (p=0.171) and Stressed subject pronoun (p=0.411) conditions did not differ from chance level performance.