Equivalent inter- and intramodality long-term priming: evidence for a common lexicon for words seen and words heard.

Weaker inter- than intramodality long-term priming of words has promoted two hypotheses: (1) separate visual and auditory lexicons and (2) modality dependence of implicit memory. In five experiments, we employed manipulations aimed to minimize study-test asymmetries between the two priming conditions. Activities at visual and auditory study were matched, words were phonologically consistent, and study modality was manipulated between subjects. Equal magnitudes of inter- and intramodality priming were found in experiments with visual and auditory stem completion at test, with visual fragment completion at test, and with visual and auditory perceptual identification at test. A within-subjects experiment yielded the conventional intramodality advantage. The results point to a single amodal lexicon and to modality-independent phonological processing as the basis of implicit word memory.

Does visual word identification involve a sub-phonemic level?

The phonological codes activated in visual word recognition can be thought of minimally as strings of discrete and unstructured phoneme-like units. We asked whether these codes might additionally express a letter string's phonological form at a featural or gestural level. Specifically, we asked whether the priming of a word (e.g. sea, film, basic) by a rhyming non-word would depend on the non-word's phonemic-feature similarity to the word. The question was asked within a mask--prime--target--mask sequence with both brief (57 ms in Experiments 1 and 2) and long (486 ms in Experiment 1) prime durations. Non-word primes that differed from their targets by a single phonemic feature (initial voicing as in ZEA, VILM, PASIC) led to faster target lexical decisions than non-word primes that differed by more than a single phonemic feature (e.g. VEA, JILM, SASIC). Visual word recognition seems to involve a sub-phonemic level of processing.

Do spelling variations affect associative and phonological priming by pseudohomophones?

A nonword prime can sound like a target word or one of the target's associates, and it can look like either without sounding like either. These pseudohomophones and pseudohomographs can vary in the number of letters shared with the target or its associate. In an associative priming experiment in which targets were named and prime duration was 125 msec within a mask-prime-mask-target sequence, pseudohomophones primed and pseudohomographs did not, with the pseudoassociative priming being only weakly affected by spelling differences. In three further experiments, prime homophony and homography were defined in respect to the target. Prime durations were 125 and 21 msec within a mask-prime-mask-target sequence and 57 msec within a mask-prime-target sequence. The superior priming by pseudohomophones was relatively insensitive to spelling. Results are discussed in terms of the phonological coherence hypothesis and the roles for orthographic information implied by the hypothesis.

Identity priming in English is compromised by phonological ambiguity.

If it takes longer to achieve a single phonological representation for inconsistent words (e.g., BOWL) than for consistent words (e.g., BENT), and if phonological coherence is pivotal to visual word recognition, then identity priming should depend on consistency. This hypothesis was evaluated in naming and lexical decision within a 4-field presentation sequence of mask-prime-mask-target. The prime-target stimulus onset asynchrony (SOA) was either 114 or 244 ms (with prime durations, respectively, of 43 and 129 ms). Four experiments compared identity primes such as BOWL and BENT, which were equated, on average, for total number of friendly and unfriendly neighbors, bigram frequency, and number of 1-letter-different neighbors. In both tasks, BENT primed itself better than BOWL primed itself, with the difference being larger at the shorter SOA. Word processing is constrained primarily by the rate of achieving a coherent phonological code.

When nonwords activate semantics better than words.

We conducted a strong test of the idea that visual word processing and the activation of a printed word's meaning proceeds at a rate scaled by the temporal evolution of a unique and stable phonological code. Using the lexical decision task, and readers fluent in the two alphabets of Serbo-Croatian, we compared the priming of a target word such as automat by the semantically related word ROBOT and by the nonword ROBOT. Whereas the Serbo-Croatian word ROBOT can support two phonological codes, /robot/ and /rovot/, the nonword ROBOT composed by illegally mixing Roman and Cyrillic letters can support only the phonological code /robot/, that corresponding to the word whose meaning is related to automat's. At a prime duration of 35 ms, the lexical decision on the target automat was facilitated by ROBOT but not by ROBOT. At a prime duration of 125 ms, the word ROBOT was the more effective prime. One consequence of phonology's leading role in visual word recognition is that a nonword can sometimes activate a given word's meaning better than the word itself.

Reading in two alphabets.

Many speakers of Serbo-Croatian read the language in two phonemically precise and partially overlapping alphabets. Twenty years of experiments directed toward this ability have led to deeper understandings of the role of speech-related processes in reading and the contrasts and similarities among the world's alphabetic writing systems.

Crystal structure of human arylsulfatase A: the aldehyde function and the metal ion at the active site suggest a novel mechanism for sulfate ester hydrolysis.

Human lysosomal arylsulfatase A (ASA) is a prototype member of the sulfatase family. These enzymes require the posttranslational oxidation of the -CH2SH group of a conserved cysteine to an aldehyde, yielding a formylglycine. Without this modification sulfatases are catalytically inactive, as revealed by a lysosomal storage disorder known as multiple sulfatase deficiency. The 2.1 A resolution X-ray crystal structure shows an ASA homooctamer composed of a tetramer of dimers, (alpha 2)4. The alpha/beta fold of the monomer has significant structural analogy to another hydrolytic enzyme, the alkaline phosphatase, and superposition of these two structures shows that the active centers are located in largely identical positions. The functionally essential formylglycine is located in a positively charged pocket and acts as ligand to an octahedrally coordinated metal ion interpreted as Mg2+. The electron density at the formylglycine suggests the presence of a 2-fold disordered aldehyde group with the possible contribution of an aldehyde hydrate, -CH(OH)2, with gem-hydroxyl groups. In the proposed catalytic mechanism, the aldehyde accepts a water molecule to form a hydrate. One of the two hydroxyl groups hydrolyzes the substrate sulfate ester via a transesterification step, resulting in a covalent intermediate. The second hydroxyl serves to eliminate sulfate under inversion of configuration through C-O cleavage and reformation of the aldehyde. This study provides the structural basis for understanding a novel mechanism of ester hydrolysis and explains the functional importance of the unusually modified amino acid.

Inhibition of naming by rhyming primes.

The priming effects of graphemically similar (e.g., HOSE) and graphemically dissimilar (e.g., ROWS) rhymes on the naming of target words (NOSE) were examined at prime-target stimulus onset asynchronies (SOA) of 36, 70, and 250 msec. A four-field presentation procedure was used of mask-prime-mask-target. The effects of rhyme primes were measured relative to those of nonrhyming control primes (CHEF, DISH) that matched the rhymes in frequency and length and shared no letters in the same positions. At SOAs of 36 and 70 msec, rhyme priming was inhibitory and equal for graphemically similar and graphemically dissimilar rhymes. At SOA = 250 msec, rhyme priming was insignificant with a tendency toward facilitation. The results are discussed in the context of (1) contrasting effects of complete versus partial phonological overlap within a prime-target pair, and (2) the hypothesis that phonological codes stabilize fastest and provide, therefore, the earliest and major constraint on word recognition.

Effects of association, frequency, and stimulus quality on naming words in the presence or absence of pseudowords.

According to classical dual-route theory, effects of associative priming and frequency on the naming of printed words arise from lexical access and should be weak or absent when word names are assembled prelexically. Assembled naming would be more likely in a shallow orthography, especially in the presence of nonwords. This hypothesis was examined with the shallow Serbo-Croatian orthography. Interactions between association, frequency, and stimulus quality were also examined in both Serbo-Croatian and English. Contrary to classical dual-route theory, both lexical effects were found for naming words in Serbo-Croatian, with or without nonwords. Neither interaction was significant in Serbo-Croatian and only association x quality was significant in English. Discussion focused on (a) the claim that lexical effects on naming in a shallow orthography constitute prima facie evidence against either prelexical phonology or the orthographic depth hypothesis, and (b) the possible factorization of frequency and active associative knowledge in naming words.

Visual lexical access is initially phonological: 2. Evidence from phonological priming by homophones and pseudohomophones.

Seven experiments were conducted that examined phonological and orthographic priming of naming using three- and four-field masking procedures with prolonged targets. Experiments 1-3 found significant phonological priming by homophones (TOWED-toad) that was independent of prime identifiability and prime-target stimulus onset asynchrony (SOA; 30, 60, or 250 ms). Subsequent experiments found significant phonological priming by pseudohomophones (TODE-toad) that was similarly independent of prime identifiability and SOA. Collectively, the limited effects of orthographic control primes (TOLD-toad, TODS-toad) and the pronounced and orthographically independent effects of phonological primes suggest (a) a leading role in visual word perception for a fast-acting, automatic, assembled phonology, and (b) a phonological basis, rather than an abstract graphemic basis, for the processing equivalency of letter variations.

Translational control of arylsulfatase A expression in mouse testis.

Arylsulfatase A is a lysosomal enzyme that is involved in the degradation of sulfated glycolipids. High levels of arylsulfatase A mRNA are found in germ cells of mouse testis. In late pachytene and secondary spermatocytes the level of arylsulfatase A mRNA is increased 20-fold when compared with other tissues. These high levels of arylsulfatase A mRNA are maintained in round spermatids and decrease in late elongating spermatids. The increase of arylsulfatase A mRNA levels is not accompanied by a similar increase in enzyme activity or polypeptides. Subcellular fractionation revealed that the majority of arylsulfatase A mRNA is not associated with polysomes but is found in fractions of lower buoyancy. The failure to become translated is ascribed to the association of arylsulfatase A mRNA with nonpolysomal ribonucleoproteins. This translational repression may be due to proteins that bind to arylsulfatase A mRNA and prevent its translation. Within the 639-nucleotide 5'-untranslated region and the 700-nucleotide 3'-untranslated region of the arylsulfatase A mRNA, we identified two regions that specifically bind proteins present in extracts prepared from testicular cells. These RNA binding proteins were absent from extracts prepared from liver or brain.

Visual lexical access is initially phonological: 1. Evidence from associative priming by words, homophones, and pseudohomophones.

In 9 experiments, a target word (e.g., frog) was named following an associate (TOAD), or a word (e.g., TOWED) or nonword (e.g., TODE) homophonic with the associate. At brief (e.g., 50 ms) stimulus onset asynchronies (SOAs), the 3 primes produced equal associative priming. At a long SOA (250 ms), priming by TOAD was matched by TODE but not by TOWED. Equal priming at brief SOAs by the 3 primes and no priming by orthographic controls (TOLD, TORD) suggests that lexical access is initially phonological. TOWED priming less than TODE at SOA = 250 ms suggests that phonologically activated representations whose input orthography does not match the addressed spelling (available only for words) are eventually suppressed. Phonological constraints on lexical access precede and set the stage for orthographic constraints.

Lexical involvement in naming does not contravene prelexical phonology: comment on Sebastián-Gallés (1991).

N. Sebastián-Gallés (1991) showed lexical involvement in naming Spanish. Her results were purported to be a failure to substantiate claims for prelexical phonology that characterize Serbo-Croatian. Summaries of several experimental demonstrations of lexical involvement in naming Serbo-Croatian are used to show that such results are only interpretable consistently in a model that assumes prelexical phonology. The lexicon is accessed through assembled phonology, but assembled and lexical phonology interact in resolving a unique pronunciation when several pronunciations are assembled and in assigning stress, which is not assembled. The authors argue that lexical access need not be different in different orthographies but that the weights on connections between orthographic and phonological substructures established through covariant learning will distinguish orthographies in the rate and degree of phonological involvement in word recognition.

Reduction in alphabet priming with delay and degradation.

Phonologically ambiguous Serbo-Croatian words are named more slowly than their phonologically unique partners. This difference is reduced by nonword primes containing consonants unique to one or the other alphabet. In 2 experiments we investigated the hypothesis that alphabet priming is the inhibition of unique and ambiguous letter units of one alphabet by the unique letter units of the other alphabet. In Experiment 1, ambiguous and unique words followed alphabet-specific nonwords at lags between 100 ms and 1,550 ms. The ambiguous-unique difference increased from 1 ms to 45 ms, consistent with a relaxing inhibitory process. In Experiment 2 we compared priming of ambiguous words with and without visual noise. Priming was less for noisy than for intact stimuli, as would be expected if noise slows processing and if the inhibition responsible for priming weakens further during the additional processing time.

Further evidence for phonological constraints on visual lexical access: TOWED primes FROG.

If the phonological codes of visually presented words are assembled rapidly and automatically for use in lexical access, then words that sound alike should induce similar activity within the internal lexicon. TOWED is homophonous with TOAD, which is semantically related to FROG, and BEACH is homophonous with BEECH, which is semantically related to TREE. Stimuli such as these were used in priming-of-naming task, in which words homophonous with associates of the target words preceded the targets at an onset asynchrony of 100 msec. Relative to spelling controls (TROD, BENCH), the low-frequency TOWED and the high-frequency BEACH speeded up the naming of FROG and TREE, respectively, to the same degree. This result was discussed in relation to the accumulating evidence for the primacy of phonological constraints in visual lexical access.

Similar attentional, frequency, and associative effects for pseudohomophones and words.

Between the presentation and recall of 1 or 5 digits, Ss performed a secondary task of naming a visually presented letter string--a pseudohomophone (e.g., FOLE, HOAP) or its real-word counterpart (FOAL, HOPE). Memory load interacted with frequency (HOPE vs. FOAL, HOAP vs. FOLE) but not with lexicality (HOPE vs. HOAP, FOAL vs. FOLE). This outcome counters models in which nonwords are named by a slow (resource-expensive) process that assembles phonology and words are named by a fast (resource-inexpensive) process that accesses lexical phonology. When the associative priming-of-naming task was secondary to the memory task, pseudohomophone associative priming (HOAP-DESPAIR, FOLE-HORSE) equaled associative priming (HOPE-DESPAIR, FOAL-HORSE) and was affected in the same way by memory load. Assembled phonology seems to underlie the naming of both words and nonwords.

Phonological access of the lexicon: evidence from associative priming with pseudohomophones.

Pseudohomophones were used in a primed naming task. In Experiments 1 and 2, target pseudowords that sounded like real words (e.g., CHARE) were preceded either by context words that related associatively to the word with which the target was homophonic (TABLE-CHARE) or by context words that were not associatively related (NOVEL-CHARE). Control pairs were TABLE-THARE and NOVEL-THARE (Experiment 1) and TABLE-CHARK and NOVEL-CHARK (Experiment 2). In relation to NOVEL, TABLE benefited the naming of CHARE but not the naming of THARE or CHARK. TAYBLE-CHAIR pairs were used in Experiment 3. If the prime TAYBLE activated/table/,then/chair/would be activated associatively and the target CHAIR would be named faster than if TARBLE was the prime. Experiment 4 extended the design of Experiment 3 to include TABLE-CHAIR pairs and a comparison of a short (280 ms) and a long (500 ms) delay between context and target onsets. The priming due to associated pseudohomophones was unaffected by onset asynchrony and equal in magnitude to that due to associated words. Results suggest that lexical representations are coded and accessed phonologically.

Is alphabet biasing in bialphabetical word perception automatic and prelexical?

Phonologically ambiguous Serbo-Croatian words are identified more slowly and erroneously than their phonologically unique counterparts. Five experiments addressed the reduction of these ambiguity effects when Roman (Cyrillic) targets are preceded by consonants unique to the Roman (Cyrillic) alphabet. Alphabet-specific nonword contexts were presented briefly with masking. With forward masking, performance was better when the phonologically ambiguous target words and their preceding nonword contexts were alphabetically congruent. Similarly, where backward masked contexts acted themselves as backward masks for the target stimuli, identification was highest when the context masks were in the same alphabet as the targets. Results were discussed in terms of automatic, prelexical processes within a network model of visual word recognition in Serbo-Croatian.

The processing of inflected words.

Is an inflected word identified by first decomposing it into stem plus suffix or, instead, is it recognized as a whole? Several lexical decision experiments studied the recognition of inflected words in English (a language with few inflections) and Serbo-Croatian (a heavily inflected language). If recognition depended on decomposition, preceding the inflection with a brief exposure of the stem (less than 100 ms) should have primed the lexical entry for the stem and, therefore, facilitated recognition of the whole inflected word that followed. It did not. It was also found that the speed of recognizing an inflected word was more strongly associated with the frequency of the whole inflected form than with the frequency of its stem. The results suggested that in word recognition, lexical contact is first made with the whole word form. Nevertheless, morphological decomposition may still occur in subsequent processing.

Phonemic similarity effects and prelexical phonology.

Ten experiments were conducted on visually presented Serbo-Croatian words and pseudowords, comprising phonemically similar and dissimilar context-target sequences. There were five main results. First, phonemic similarity effects in both lexical decision and naming are independent of graphemic similarity. Second, phonemic similarity need not facilitate lexical decision; the direction of its effect depends on lexicality, target frequency, and type of similarity (specifically, the position of the phoneme that distinguishes context and target). Third, phonemic similarity expedites the naming of words and pseudowords, and to the same degree. Fourth, phonemic similarity is negated in naming, but not in lexical decision, when the visually presented context and target are stressed differently. Fifth, the phonemic similarity effect occurs even when the context is a masked pseudoword. These results are discussed in terms of a model in which word-processing units are activated routinely by phoneme-processing units, and in which compositionally similar word units, when activated, inhibit one another in proportion to each's familiarity. In this model, the phonemic similarity effect in naming is based on the states of phoneme units, whereas the phonemic similarity effect in lexical decision is based on the states of word units. Overall, the results comport with an account in which phonology is computed prelexically and automatically.