Examining speech motor planning difficulties in apraxia of speech and aphasia via the sequential production of phonetically similar words.

This study investigated the underlying nature of apraxia of speech (AOS) by testing two competing hypotheses. The Reduced Buffer Capacity Hypothesis argues that people with AOS can plan speech only one syllable at a time Rogers and Storkel [1999. Planning speech one syllable at a time: The reduced buffer capacity hypothesis in apraxia of speech. Aphasiology, 13(9-11), 793-805. https://doi.org/10.1080/026870399401885]. The Program Retrieval Deficit Hypothesis states that selecting a motor programme is difficult in face of competition from other simultaneously activated programmes Mailend and Maas [2013. Speech motor programming in apraxia of speech: Evidence from a delayed picture-word interference task. American Journal of Speech-Language Pathology, 22(2), S380-S396. https://doi.org/10.1044/1058-0360(2013/12-0101)]. Speakers with AOS and aphasia, aphasia without AOS, and unimpaired controls were asked to prepare and hold a two-word utterance until a go-signal prompted a spoken response. Phonetic similarity between target words was manipulated. Speakers with AOS had longer reaction times in conditions with two similar words compared to two identical words. The Control and the Aphasia group did not show this effect. These results suggest that speakers with AOS need additional processing time to retrieve target words when multiple motor programmes are simultaneously activated.

A behavioral database for masked form priming.

Reading involves a process of matching an orthographic input with stored representations in lexical memory. The masked priming paradigm has become a standard tool for investigating this process. Use of existing results from this paradigm can be limited by the precision of the data and the need for cross-experiment comparisons that lack normal experimental controls. Here, we present a single, large, high-precision, multicondition experiment to address these problems. Over 1,000 participants from 14 sites responded to 840 trials involving 28 different types of orthographically related primes (e.g., castfe-CASTLE) in a lexical decision task, as well as completing measures of spelling and vocabulary. The data were indeed highly sensitive to differences between conditions: After correction for multiple comparisons, prime type condition differences of 2.90 ms and above reached significance at the 5% level. This article presents the method of data collection and preliminary findings from these data, which included replications of the most widely agreed-upon differences between prime types, further evidence for systematic individual differences in susceptibility to priming, and new evidence regarding lexical properties associated with a target word's susceptibility to priming. These analyses will form a basis for the use of these data in quantitative model fitting and evaluation and for future exploration of these data that will inform and motivate new experiments.

Attention, intention and domain-specific processing.

Many researchers use subliminal priming to investigate domain-specific processing mechanisms, which have classically been defined in terms of their autonomy from other cognitive systems. Surprisingly, recent research has demonstrated that nonconsciously elicited cognitive processes are not independent of attention. By extension, these findings have been used to call into question the autonomy of domain-specific processing mechanisms. By contrast, we argue that the demonstrated modulation of nonconscious cognitive processes by attention occurs at a predomain-specific stage of processing. Thus, although we agree that attention might be a prerequisite of nonconscious processes, we suggest that there is no reason to think that higher-level cognitive systems directly modulate domain-specific processes.

Speech motor planning in the context of phonetically similar words: Evidence from apraxia of speech and aphasia.

The purpose of this study was to test two competing hypotheses about the nature of the impairment in apraxia of speech (AOS). The Reduced Buffer Capacity Hypothesis argues that people with AOS can hold only one syllable at a time in the speech motor planning buffer. The Program Retrieval Deficit Hypothesis, states that people with AOS have difficulty accessing the intended motor program in the context where several motor programs are activated simultaneously. The participants included eight speakers with AOS, most of whom also had aphasia, nine speakers with aphasia without AOS, and 25 age-matched control speakers. The experimental paradigm prompted single word production following three types of primes. In most trials, prime and target were the same (e.g., bill-bill). On some trials, the initial consonant differed in one phonetic feature (e.g., bill-dill; Similar) or in all phonetic features (fill-bill; Different). The dependent measures were accuracy and reaction time. The results revealed a switch cost - longer reaction times in trials where the prime and target differed compared to trials where they were the same words - in all groups; however, the switch cost was significantly larger in the AOS group compared to the other two groups. These findings are in line with the prediction of the Program Retrieval Deficit Hypothesis and suggest that speakers with AOS have difficulty with selecting one program over another when several programs compete for selection.

The rank hypothesis and lexical decision: a reply to Adelman and Brown (2008).

J. S. Adelman and G. D. A. Brown (2008) provided an extensive analysis of the form of word frequency and contextual diversity effects on lexical decision time. In this reply, the current authors suggest that their analysis provides a valuable tool for the evaluation of models of lexical access and that the results they report are broadly supportive of the rank hypothesis suggested by W. S. Murray and K. I. Forster (2004)--more supportive, in fact, than the originally reported data. However, Adelman and Brown's conclusion that the results of these analyses can be taken as evidence against rank (and thereby serial models of lexical access) and for instance models is rejected. It is shown that at least one instance model makes the wrong predictions and that Adelman and Brown's conclusions rest on the assumption that lexical decision time presents a pure measure of the time involved in lexical access. Results from eye tracking are reported, which also support a rank account, as do results from analyses that show that a log frequency account is clearly inadequate. Finally, it is demonstrated that, unlike other models, the rank account continues to make accurate predictions regarding the form of both reaction time and error rate effects.

Being forward not backward: lexical limits to masked priming.

This study investigated whether masked priming is mediated by existing memory representations by determining whether nonwords targets would show repetition priming. To avoid the potential confound that nonword repetition priming would be obscured by a familiarity response bias, the standard lexical decision and naming tasks were modified to make targets unfamiliar. Participants were required to read a target string from right to left (i.e., "ECAF" should be read as "FACE") and then make a response. To examine if priming was based on lexical representations, repetition primes consisted of words when read forwards or backwards (e.g., "face", "ecaf") and nonwords (e.g., "pame", "emap"). Forward and backward primes were used to test if task instruction affected prime encoding. The lexical decision and naming tasks showed the same pattern of results: priming only occurred for forward primes with word targets (e.g., "face-ECAF"). Additional experiments to test if response priming affected the LDT indicated that the lexical status of the prime per se did not affect target responses. These results showed that the encoding of masked primes was unaffected by the novel task instruction and support the view that masked priming is due to the automatic triggering of pre-established computational processes based on stored information.

Unconscious cognition isn't that smart: modulation of masked repetition priming effect in the word naming task.

Masked repetition primes produce greater facilitation in naming in a block containing a high, rather than low proportion of repetition trials. [Bodner, G. E., & Masson, M. E. J. (2004). Beyond binary judgments: Prime-validity modulates masked repetition priming in the naming task. Memory & Cognition, 32, 1-11] suggested this phenomenon reflects a strategic shift in the use of masked prime as a function of its validity. We propose an alternative explanation based on the Adaptation to the statistics of the environment (ASE) framework, which suggests the proportion effect reflects adaptation of response-initiation processes to recent trial difficulty. Consistent with ASE's prediction, (1) stimuli that produce the proportion effect also produced an "asymmetric blocking effect", showing a smaller fall in response latencies of hard items than the rise of easy items when the two item types were intermixed relative to pure blocks comprised of only one item type, and (2) manipulation of prime validity was neither necessary nor sufficient to modulate the size of masked-priming effect.

Is the L2 lexicon different from the L1 lexicon? Evidence from novel word lexicalization.

Studies on the representation of newly learned words in the native language show that after repeated sessions of learning, novel words produce less form priming than nonwords when they are used as primes in a masked priming experiment. This suggests that the newly learned words have established lexical representations, and therefore start to behave more like real words than nonwords (Qiao & Forster, 2013). Since adult language learning normally happens in a foreign language context rather than in the native language context, it is important to see whether similar results could be obtained if bilingual subjects were taught novel words in their second language (L2) rather than their first language (L1). The current experiment explores this issue using the same procedure and materials as used in the L1 experiment. Results show that in contrast to the nonsignificant priming observed with the L1 speakers, L2 speakers show enhanced facilitatory priming after the same training process. In addition, a significant facilitatory priming effect is also obtained with real words as primes, suggesting that the L1 and L2 lexicons might work in rather different ways. One possibility is that the L2 lexicon is not represented in the same type of memory system as the L1 lexicon, rather it is represented in a system where competitive effects are not observed.

Orthographic structure versus morphological structure: principles of lexical organization in a given language.

Most models of visual word recognition in alphabetic orthographies assume that words are lexically organized according to orthographic similarity. Support for this is provided by form-priming experiments that demonstrate robust facilitation when primes and targets share similar sequences of letters. The authors examined form-orthographic priming effects in Hebrew, Arabic, and English. Hebrew and Arabic have an alphabetic writing system but a Semitic morphological structure. Hebrew morphemic units are composed of noncontiguous phonemic (and letter) sequences in a given word. Results demonstrate that form-priming effects in Hebrew or Arabic are unreliable, whereas morphological priming effects with minimal letter overlap are robust. Hebrew bilingual subjects, by contrast, showed robust form-priming effects with English material, suggesting that Semitic words are lexically organized by morphological rather than orthographic principles. The authors conclude that morphology can constrain lexical organization even in alphabetic orthographies and that visual processing of words is first determined by morphological characteristics.

Forty-five years after Broadbent (1958): still no identification without attention.

According to D. E. Broadbent's (1958) selective filter theory, people do not process unattended stimuli beyond the analysis of basic physical properties. This theory was later rejected on the basis of numerous findings that people identify irrelevant (and supposedly unattended) stimuli. A careful review of this evidence, however, reveals strong reasons to doubt that these irrelevant stimuli were in fact unattended. This review exposed a clear need for new experiments with tight control over the locus of attention. The authors present 5 such experiments using a priming paradigm. When steps were taken to ensure that irrelevant stimuli were not attended, these stimuli produced no priming effects. Hence, the authors found no evidence that unattended stimuli can be identified. The results support a modern version of Broadbent's selective theory, updated to reflect recent research advances.

Category size effects revisited: frequency and masked priming effects in semantic categorization.

Previous work indicates that semantic categorization decisions for nonexemplars (e.g., deciding that TURBAN is not an animal name) are faster for high-frequency words than low-frequency words. However, there is evidence that this result might depend on category size. When narrow categories are used (e.g., Months, Numbers), there is no frequency effect for nonexemplars. This result is confirmed, and is explained in terms of a category search model, which allows a "No" decision to be generated without access to the lexical entry for the target word. This explains the absence of a frequency effect, but not the presence of a strong masked repetition priming effect, which is assumed to have a lexical source. It is shown that this effect may not be lexical, since nonwords also show similar priming. Both of these priming effects disappear when a larger category is used. This pattern of results is explained on the assumption that category search is only possible with small categories, and that tentative category decisions are generated for the unconsciously perceived prime, which leads to a marked response congruence effect.

Novel word lexicalization and the prime lexicality effect.

This study investigates how newly learned words are integrated into the first-language lexicon using masked priming. Two lexical decision experiments are reported, with the aim of establishing whether newly learned words behave like real words in a masked form priming experiment. If they do, they should show a prime lexicality effect (PLE), in which less priming is obtained due to form similarity when the prime is a word. In the first experiment, subjects were taught the meanings of novel words that were neighbors of real words, but no PLE was observed; that is, equally strong form priming was obtained for both trained and untrained novel primes. In the second experiment, 4 training sessions were spread over 4 weeks, and under these conditions, a clear PLE was obtained in the final session. It is concluded that lexicalization requires multiple training sessions. Possible explanations of the PLE are discussed.

How L2 words are stored: the episodic L2 hypothesis.

This article reports findings from 3 experiments examining whether 2nd language (L2) words are represented in episodic memory, as originally proposed by Jiang and Forster (2001). Experiment 1 was a direct replication of Jiang and Forster, testing highly proficient Chinese-English bilinguals. Masked translation priming was obtained in an episodic recognition task from L2 to the 1st language (L1) for studied "old" L1 targets but not for unstudied "new" targets. This experiment also confirmed the translation asymmetry generally found in lexical decision tasks, namely, priming in the L1-L2 direction but not in the L2-L1 direction. Experiment 2 showed that recently learned words in an unfamiliar language (therefore, words that are obviously represented episodically) could also prime their L1 translations in an episodic recognition task but not in a lexical decision task. Finally, in Experiment 3, masked repetition priming was used with an episodic recognition memory task. For native speakers of English, repetition (L1-L1) priming is obtained only for old words, because there is no episodic representation for new words. However, Chinese-English bilinguals tested with the same items showed repetition (L2-L2) priming for both old and new words, indicating that the new L2 words were represented episodically as well. Overall, the results from these 3 experiments support the hypothesis that L2 words are represented in episodic memory. Finally, the mechanisms behind why L2-L1 translation priming can be obtained in episodic recognition and not in lexical decision are discussed.

Dynamic adaptation to history of trial difficulty explains the effect of congruency proportion on masked priming.

In reaction time research, there has been an increasing appreciation that response-initiation processes are sensitive to recent experience and, in particular, the difficulty of previous trials. From this perspective, the authors propose an explanation for a perplexing property of masked priming: Although primes are not consciously identified, facilitation of target processing by a related prime is magnified in a block containing a high proportion of related primes and a low proportion of unrelated primes relative to a block containing the opposite mix (Bodner & Masson, 2001). In the present study, this phenomenon is explored with a parity (even/odd) decision task in which a prime (e.g., 2) precedes a target that can be either congruent (e.g., 4) or incongruent (e.g., 3). It is shown that the effect of congruence proportion with masked primes cannot be explained in terms of the blockwise prime-target contingency. Specifically, with masked primes, there is no congruency disadvantage in a block containing a high proportion of incongruent primes, but there is a congruency advantage when the block contains an equal proportion of congruent and incongruent primes. In qualitative contrast, visible primes are sensitive to the blockwise prime-target contingency. The authors explain the relatedness proportion effect found with masked primes in terms of a model according to which response-initiation processes adapt to the statistical structure of the environment, specifically the difficulty of recent trials. This account is supported with an analysis at the level of individual trials using the linear mixed effects model.

The maze task: measuring forced incremental sentence processing time.

The maze task is an online measure of sentence processing time that provides an alternative to the standard moving window version of self-paced reading. Rather than each word of the sentence being presented in succession, two words are presented at the same time, and the participant must choose which word is a grammatical continuation of the sentence. This procedure forces the reader into an incremental mode of processing in which each word must be fully integrated with the preceding context before the next word can be considered. Previous research with this technique has not considered whether it is sufficiently sensitive to syntactic complexity effects or to garden path effects. Four experiments are reported demonstrating that reliable differences in processing time for subject relatives and object relatives can be obtained, and that this technique generates garden path effects that correspond closely with the data from eyetracking experiments, but without the spillover effects that are sometimes obtained with eyetracking. It is also shown that the task is sensitive to word frequency effects, producing estimates well in excess of those found with eyetracking.

Cascaded versus noncascaded models of lexical and semantic processing: the turple effect.

The density of the orthographic neighborhood surrounding an item has been shown to have an inhibitory effect for nonwords in a lexical decision experiment. Four experiments are reported investigating whether a similar pattern holds for a semantic categorization task (animal vs. non-animal). In the first experiment, no effects of neighborhood density were found for nonexemplars, whether they were words or nonwords. The absence of any inhibitory effect for nonwords implies that close orthographic neighbors are ignored. However, the second experiment showed that if the nonword has a neighbor that is an animal name (eg., turple), an interference effect is observed, implying that neighbors do exert an effect if they have the right semantic properties. The same items showed no additional interference in lexical decision. These results suggest the involvement of semantic properties very early in the processing cycle. A cascaded processing system monitoring activation in semantic features can explain these results, but cannot explain the frequency effect observed for nonexemplar words or the fact that variation in density is irrelevant when one of the neighbors is an exemplar. It is argued that existing models of semantic categorization must be extended to accommodate these results.

DMDX: a windows display program with millisecond accuracy.

DMDX is a Windows-based program designed primarily for language-processing experiments. It uses the features of Pentium class CPUs and the library routines provided in DirectX to provide accurate timing and synchronization of visual and audio output. A brief overview of the design of the program is provided, together with the results of tests of the accuracy of timing. The Web site for downloading the software is given, but the source code is not available.