Grammatical gender retrieval in aphasic patients

3.5 Vulnerability of grammatical gender

3.5.1 Grammatical gender retrieval in aphasic patients

A milestone in the investigation of GG retrieval in aphasia are the data presented in Luzzatti and De Bleser (1996), (see also De Bleser, Bayer, Luzzatti (1996)): authors report the case of two native Italian speakers with acquired language disorders due to an aneurysm, in one case, and a head injury, in the other. Both subjects undergo the tests a

few years after the onset of their aphasia, which manifests with agrammatic spontaneous speech. Moreover, participants have a medium-to-mild impairment in sentence repetition and naming, and disrupted comprehension of both active and passive sentences. The study comprehends eight tasks concerning lexical morphology; in particular, participants perform the following ones: gender production in simple nouns and proper names, gender agreement in noun-adjective phrases, gender production in derived nouns, gender production in compounds, pluralization and singularization of simple nouns, pluralization of compound nouns, production of prepositions in prepositional compounds and production of adjectival derivational suffixes. The material in use in the study is very extensive, as well as the amount of collected data is; therefore, in what follows, I will limit my attention to the results from the tasks on gender retrieval, the most interesting one for the sake of the present discussion.

Overall, De Bleser and Luzzatti (1996) report that their patients have different gradients of proficiency depending on the nature of the experimental material in use, with a clear dissociation between simple and compound nouns, being the former better preserved than the latter. Roughly speaking, both subjects seems to retain a good competence on simple nouns, while compounds represent a weak point in their lexical competence; nonetheless, a closer look at the data actually reveals some signs of impairment on simple nouns too, especially in the case of the patient suffering from a severe brain injury. Problems arise in particular in the following domains: gender retrieval is often unsuccessful for opaque nouns ending in -e (declension Class III in Chini (1995)), which are classified as masculine. The same happens for irregular feminine words ending in -o (e.g., mano, 'hand.F', from declension Class VII in Chini, 1995). Data suggest the onset of a rough gender generalization, allowed by the disregard of lexical knowledge and the reliance on morphological rules. As for the task on gender-agreement in simple noun-adjective phrases, both participants achieve high rates of accuracy, most probably thanks to their capacity to rely on gender cues, provided by the determiner of the phrases to be completed. It is also interesting to point out that the performance improves in derived nouns ending with -e: this suggests that subjects are sensitive to the grammatical information contained in the derivational suffix and actually process nouns like malore ('sudden illness.M') differently from nouns like cane ('dog.M'). In the former, the suffix -ore is recognized as a bearer of masculine GG, while nouns like cane provide no

morphological cue. This last result is not surprising, especially in the light of other studies, which proved umimpaired speakers’ capacity to break down words into their constituent morphemes during word recognition (Marslen-Wilson et al., 1994; Meinzer et al., 2009).

The status of GG retrieval in agrammatic patients is still debated though, given that attempts to replicate the results presented in Luzzatti and De Bleser (1996) were only partially successful for other languages. For example, Bastiaanse et al. (2003) collected data from ten German and nine Dutch speakers with Broca´s aphasia, and found virtually at-ceiling performance on GG retrieval in task requiring either sentence completion or production. This is a particularly surprising result if we consider the involvement of Broca’s area in GG retrieval, as exemplified in paragraph 3.4.1. However, as anticipated, GG assumes very specific characteristics depending on the language, and this should dissuade researchers from relying on cross-linguistic generalizations.

Moreover, as cited above, failures in word recall attempts can be a rich source of information on how lexical retrieval works and how proficient speakers are at it. I refer in particular to studies examining paraphasias and TOT states. Badecker et al. (1995) describe the performance of Dante, a young Italian speaker affected by anomia²⁸, in picture naming and in sentence completion tasks. When the subject is in an anomic state, experimenters ask him questions about the word he is trying to retrieve. Questions concern GG, first and final phonemes, length of the word and similarity to other words.

Through questions, Badecker et al. (1995) unveil a clear dissociation in Dante´s ability between grammatical gender (very accurately produced) and information about the phonological and orthographic forms (poorly recalled), with no effects of regularity, meaning that GG is equally well retrieved for both regular and irregular items. Dante also completes a gender-decision task based on the nouns he has not retrieved in previous tasks. Again, his performance is very accurate: he correctly retrieves the grammatical gender of words he failed to activate in previous tasks (98%). Authors read the results as a proof of the fact that anomic patients have access to grammatical information about target nouns, meaning that activation of the target lemma is successful, while they fail at selecting the proper phonological nodes, necessary for the word spell out. With reference to the model of lexical retrieval first suggested by Levelt (1989), Badecker et al. (1995)

28 Dante was affecteded by amnesia and anomia as a consequence of a long comatose state, most probably due to a meningoencephalitis. Badecker et al. (1995) describe his spontaneous speech as fluent, despite anomia.

claim that syntactic information (the lemma) precedes (and maybe it even is a prerequisite for) the activation of phonological information (the lexeme). Based on these assumptions, authors set the locus of impairment for anomic patients in-between the lemma and the lexeme levels: that is where the flow of activation is interrupted and word retrieval is blocked.

Not all researchers agree on the hypothesis above. The capacity to retrieve GG despite unsuccessful word activation is ascribed by Friedmann and Biran (2003) to language specific phenomena. Basing their speculation on data from Hebrew anomic speakers, who actually do not show gender congruency on their paraphasias, the authors claim that the capacity to retrieve GG is biased by syntactic constraints, which are language-specific. In doing so, they refuse to take into account impairments more directly linked to the word retrieval process, for which a universal (and therefore homogeneous across languages) model should be assumed. In Friedmann and Biran´s (2003) view, it is therefore incorrect to claim that agrammatic speakers usually preserve GG knowledge.

Rather, GG retrieval depends on how nouns are usually implemented in the syntactic derivation of the language at stake. The lower the acceptance of bare nouns in the syntax is, the more frequently speakers produce well-formed DPs rather than bare nouns, and therefore the better GG is retrieved.

It is important to consider that anomia does not strictly imply semantic deficits.

That is a macroscopic difference with respect to PADs, who actually have been extensively reported to suffer from severe semantic deficit too: in their case, anomia is most probably the ultimate consequence of erosion of semantic information. It is therefore not possible and fruitful to directly compare speakers affected by different kinds of impairments. The reviewed studies are nonetheless interesting for the purpose of pointing out information concerning GG retrieval and how vulnerable (or not) it might be.

In order to complete the overview in GG retrieval and get gradually closer to the main focus of the present study, in the following paragraph I will review two studies from background literature, both of which deal with the competence and sensitivity of PADs on linguistic tasks involving grammatical gender.

82 3.6 Grammatical gender in PADs

Among the numerous symptoms of AD, anomia appears quite early and persists along with the worsening of the disease. Researchers devoted much attention to the phenomenon and many agree on recognizing a number of causes to anomia, as well as few consequences affecting different levels of linguistic competence. Among these, the ability to compute complex clause structures decreases (Small et al., 2000; Waters, Rochon and Caplan, 1998). Overall, no major disruption has been reported concerning gender, but I should also say that the phenomenon has not received much attention so far.

Previous literature provides two studies addressing the status of GG in PADs, with the purpose of investigating language processing at the lexical and sentential levels. The two studies I am going to review both focus on Italian-speaking subjects, while they tackle the issue from different perspectives: Paganelli et al. (2003) investigate whether PADs manage to retrieve GG despite failing at completing lexeme activation; their purpose is to find out at which stage the process of lexical retrieval is impaired. Manenti et al. (2004) focus on sentence processing and investigate the effects of gender priming in combination with semantic priming.

Paganelli et al. (2003) enrol seven Italian-speaking PADs and compare their performance on two picture-naming tasks to that of unimpaired controls. Both tasks include 170 stimuli, selected according to a combination of regular (declension Class I and II) and opaque items (declension Class III): in the first task, authors ask participants to name objects by their bare noun; in the second, they ask participants to produce complete DPs (determiner + NP). Controls perform differently in the two experimental conditions: in the former (bare noun naming), they do not have any consistent gender congruency effect: when they fail at retrieving the target word, their outputs is not of the same GG as the expected word. A gender effect (i.e., the mistake bears the same GG as the target word) arises in the latter condition, when a DP is expected. PADs never have a gender congruency effect in their naming failures, independently of the conditions in use. In other words, the activation of syntactic frames (the DPs) influence the performance of normal controls, but not the one of PADs, meaning that the two observed groups experience failures at different levels. Normal controls succeed in activating the proper semantic nodes and the activation flows up to the required syntactic frames; failures ultimately arise just before the selection of the target lexeme. At that point, only

alternatives compatible with the already activated syntactic frame are admitted. The mistake is then constrained by the activated syntactic information, namely gender. On the other hand, patients mainly produce semantic errors with no higher-than-chance gender congruency, which means that their mistakes are generated pre-lexically, at the conceptual level, before the activation of syntactic information. The authors posit then the locus of disruption at the semantic level and investigate gender only as a marker of the border in-between two different stages of lexical retrieval. In my view, the phenomenon deserves more attention; we should indeed consider that it could also be the case that, on top of the mis-selection of semantic alternatives, ineffective construction of adequate syntactic conditions co-occurs, further favouring naming mistakes.

Manenti et al. (2004) adopt an on-line testing paradigm in order to investigate PADs´ ability to take advantage of semantic and gender priming cues while processing orally presented sentences. They also address the converse capacity to inhibit erroneous alternatives, with interesting results. Stimuli are short two-sentence narratives, with a target word presented visually. Participants listen to the narrative (in 6) and complete it by reading out aloud the provided target nouns (in 7). The semantic cue to target nouns is given by the sentence meaning, while gender cue is provided by the determiner, which is always the last word the participants hear before seeing the visual target. The task includes four conditions: in the first one, both semantic and gender cues are congruent with the target (7a); in the second (7b) and in the third (7c) conditions, only one of the two cues is congruent (either the semantic or the gender one); in the fourth condition (7d), neither of the two factors contributes to correctly priming the target word.

(6) Quando vado a letto prima di addormentarmi leggo sempre 'When I go to bed before falling asleep I always read'

(7) a. un LIBRO 'a.M book.M' b. un TOPO 'a.M mouse.M' c. una LIBRO 'a.F book.M'

84 d. una TOPO

'a.F mouse.M'

Reading times are measured and results reveal different performance patterns across controls and PADs. Overall, young and elderly controls clearly have a facilitation effects in reaction to positive semantic and gender priming (7a). PADs, instead, experience interference too, on top of facilitating effects. In other words, PADs benefit from combined semantic and gender priming (7a) and they can process faster and more accurately the first condition. Moreover, incongruence of combined priming cues is hard for them to inhibit and it results in slower RTs (in 7b and 7c). The performance is therefore compatible with preservation and integration of grammatical knowledge in sentence processing. What actually appears problematic is the inhibition of alternatives and incongruent priming cues.

In conclusion, the two studies I reviewed above brought to different insights into the processing of gender features by PADs. On the one side, Paganelli et al. (2003) underline the relative irrelevance of grammatical information activation in the process of lexical selection, given that lexical disruption takes place at the preceding semantic level;

on the other, Manenti et al. (2004) confirm the active role played by gender priming in combination with semantic priming in lexical activation during sentence processing.

Indeed, their patients read a sentence’s final word faster if this is primed both by semantic and syntactic cues (a determiner bearing the correct grammatical gender), while their reaction times are longer in correspondence to incongruent primers.

3.7 Conclusions

The review of background literature was useful to observe how GG is a very uneven category across languages. Still, with respect to Italian, studies pointed out the following information:

a) Italian has a mixed system with respect to transparency of final morpheme of nouns: the majority of words is transparent, many are opaque, few are irregular (Chini, 1995).

b) GG does not have a dedicated projection in the functional domain of DP (Alexiadou, 2004; Carstens, 2000); nonetheless, it plays a relevant role both at the

syntactic level and at PF: it allows feature-sharing and agreement both inside the DP (e.g., on determiner and modifiers), and outside the DP (e.g., on past participle and pronouns).

c) Most nouns have intrinsic GG, which is assigned arbitrarily and independently of semantic, morphological and phonological information; the relevant feature is stored in the lexicon attached to the lemma node and is retrieved whenever the noun is activated (Caramazza, 1997; Caramazza and Miozzo, 1997; Levelt, 1989;

Vigliocco et al., 1997). In some other cases, GG is assigned inherently through a checking operation with the [+human/+animate] referent in the context (Alexiadou, 2004; Di Domenico, 1997; Franzon et al., 2014). That is the case of word pairs like ragazzo/ragazza ('boy.M'/'girl.F').

d) There exists a double-route to gender retrieval. Results from psycholinguistic research provide evidence both in favour of direct access to the abstract feature in the lexicon and of form-based retrieval of GG (Badecker et al., 1995; Bates et al., 1995; Gollan and Frost, 2001)). The relevance of the two routes to GG activation might depend on the specific linguistic system at stake and, in particular, on how transparent or opaque this is.

e) Broca’s area plays a prominent role in the neural circuits engaged in GG retrieval (Heim, 2008).

f) Gender is a vulnerable piece of knowledge. The claim is based on the observation of GG in specific linguistic conditions like unbalanced bilingualism (Bianchi, 2013), interrupted L1 acquisition (Anderson, 1999; Håkansson, 1995), and acquired linguistic disorders (Luzzatti and De Bleser, 1996 a.m.o.).

4 GRAMMATICAL GENDER RETRIEVAL IN PATIENTS WITH ALZHEIMER´S DISEASE

4.0 Introduction

In the present Chapter, I present results from a gender retrieval task performed by Italian PADs. The reasons for investigating this field mainly resides in the nature of grammatical gender (GG). GG is a very interesting linguistic element that involves a number of linguistic levels and competences: it is stored in the lexicon as part of the lexical entry and it brings along a syntactic value, which is relevant in the syntactic derivation.

Moreover, it also has a morphological and phonological manifestation. To a certain extent, it belongs to the class of procedural components of linguistic competence, but it also implies declarative knowledge, as in the case of opaque and irregular nouns (see Chapter 3). Investigations on GG retrieval could therefore be highly informative on the linguistic competence of PADs.

The chapter is organized as follows: in 4.1 I report the research questions I intend to address in the present study; section 4.2 presents information concerning the materials in use, participants, procedure and coding guidelines. In 4.3 I provide results; these are further discussed in 4.4.

4.1 Research questions

In light of the background literature I have reviewed in the previous chapter, I would like to address three research questions concerning GG in PADs.

The first focus of my interest will be the kind of strategy PADs adopt in order to access GG. There exist two different, but complementary, routes to GG: one consists of direct access to the GG information stored in the mental lexicon, the second exploits form-based GG retrieval. The former always guarantees successful retrieval, while the latter works safely only on transparent nouns. I investigate whether PADs change the way they employ these two routes as a reaction to altered linguistic and cognitive abilities. As discussed in Chapter 2, PADs have shown to be more spared on procedural rather than

on declarative components of the language. For instance, PADs show a clear tendency to modify irregular verb forms by applying regular morphology, thus performing an operation of over-regularization (Colombo et al., 2009; Walenski et al., 2009). In order to answer the question in the present study, PADs complete a gender retrieval task including transparent, opaque and irregular nouns. If the generalization about spared procedural mechanisms with respect to declarative components is correct, I should find a specific impairment on opaque and irregular nouns, in association with strategies of systematic regularization. If not, the three categories (transparent, opaque and irregular nouns) should be equally (un)affected by mistakes on GG retrieval.

Second, I intend to investigate the role of natural gender in grammatical gender retrieval. In unimpaired speakers, natural gender is not relevant, or at least Bates et al.

(1995) do not find any facilitation effects for words endowed with natural gender with respect to the inanimate ones. Still, there are reasons to assume that this might not be the case for PADs. The doubt is worth trying to shed light on the topic. It is well-known that PADs suffer from severe anomia, most probably due to semantic erosion and loss of world knowledge (see Chapter 2). This process of progressive semantic information loss first starts by affecting fine-grained information and then spreads on. Consequently, speakers increasingly regress to core semantic macro-categories. This disruption and reorganization at the semantic level might have consequences at the syntactic one. In other words, a plausible hypothesis to be tested is whether natural gender could be employed as a compensating strategy in case of difficulties on GG retrieval. If the hypothesis is correct, PADs should present a dissociation between nouns whose referents are endowed with natural gender, and nouns that refer to inanimate referents. That is the reason for including both kinds of nouns in the material in use in the present study.

The third question I want to address concerns the role of derivational morphology in GG retrieval. I recalled in Chapter 3 that Luzzatti and De Bleser (1996) found a dissociation between words belonging to the opaque class of nouns ending in -e: the presence of derivational morphology seems to facilitate the performance in comparison

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