The Role of Co-Occurrence Statistics in Developing Semantic Knowledge

The organization of our knowledge about the world into an interconnected network of concepts linked by relations profoundly impacts many facets of cognition, including attention, memory retrieval, reasoning, and learning. It is therefore crucial to understand how organized semantic representations are acquired. The present experiment investigated the contributions of readily observable environmental statistical regularities to semantic organization in childhood. Specifically, we investigated whether co-occurrence regularities with which entities or their labels more reliably occur together than with others (a) contribute to relations between concepts independently and (b) contribute to relations between concepts belonging to the same taxonomic category. Using child-directed speech corpora to estimate reliable co-occurrences between labels for familiar items, we constructed triads consisting of a target, a related distractor, and an unrelated distractor in which targets and related distractors consistently co-occurred (e.g., sock-foot), belonged to the same taxonomic category (e.g., sock-coat), or both (e.g., sock-shoe). We used an implicit, eye-gaze measure of relations between concepts based on the degree to which children (N = 72, age 4–7 years) looked at related versus unrelated distractors when asked to look for a target. The results indicated that co-occurrence both independently contributes to relations between concepts and contributes to relations between concepts belonging to the same taxonomic category. These findings suggest that sensitivity to the regularity with which different entities co-occur in children's environments shapes the organization of semantic knowledge during development. Implications for theoretical accounts and empirical investigations of semantic organization are discussed.     

Dissociative effects of phonological vs. semantic associates on recognition memory in the Deese/Roediger-McDermott paradigm

Using a variation of the Deese/Roediger–McDermott paradigm in four experiments, we examined hit rate, false alarm rate, and memory discriminability (d′) for critical items (e.g., sleep) after their semantic associates (e.g., dream, rest, and awake), phonological associates (e.g., bleep, sheep, and cheap) or unrelated items were studied. Replicating previous research (e.g., Neely & Tse, 2007), d′ was lower for critical items than for yoked associates in semantic lists. However, d′ was higher for critical items than for yoked associates in phonological lists, even when the same critical items were used for these two list types. The memory discriminability of critical items was enhanced by phonological lists via a larger increase in their hit rates than in their false alarm rates, relative to the same critical items in lists of unrelated words. These findings (a) could not be fully accounted for by the activation-based theories proposed in the false memory literature, and (b) may suggest that the memory discriminabilities of semantic and phonological lists are modulated by two distinct activation mechanisms.     

Well‐Hidden Regularities: Abstract Uses of in and on Retain an Aspect of Their Spatial Meaning

Prepositions name spatial relationships (e.g., book on a table). But they are also used to convey abstract, non‐spatial relationships (e.g., Adrian is on a roll)—raising the question of how the abstract uses relate to the concrete spatial uses. Despite considerable success in delineating these relationships, no general account exists for the two most frequently extended prepositions: in and on. We test the proposal that what is preserved in abstract uses of these prepositions is the relative degree of control between the located object (the figure) and the reference object (the ground). Across four experiments, we find a continuum of greater figure control for on (e.g., Jordan is on a roll) and greater ground control for in (e.g., Casey is in a depression). These findings bear on accounts of semantic structure and language change, as well as on second language instruction.     

With a letter-searched prime, boat primes float but swim and coat don't: further evidence for automatic semantic activation

Letter search (LS) on the prime typically eliminates semantic priming (swim-float) and orthographic/phonological (O/P) priming (coat-float) but not morphological priming (marked-mark). However, LS on the prime does not reduce semantic priming for low-frequency targets (Tse & Neely, 2007). These findings suggest that semantic activation survives LS but decays during LS to a low level that can be detected only with sensitive measures, which are afforded by low-frequency targets and morphologically related primes and targets. In the present research, we show that LS on the prime results in 0 msec of semantic priming (e.g., swim-float) and 11 msec of O/P priming (e.g., coat-float), both of which are statistically null, whereas the LS semantic+O/P priming effect for primes and targets that do not share a morpheme (e.g., boat-float) is a robust 37 msec. Discussion focuses on the automaticity of semantic activation and whether morphological priming is mediated by (1) a morphemic representation that is separate from semantic representations or (2) activation combined from semantics and orthography/phonology.     

Making sense of word senses: the comprehension of polysemy depends on sense overlap

Studies of polysemy are few in number and are contradictory. Some have found differences between polysemy and homonymy (L. Frazier & K. Rayner, 1990), and others have found similarities (D. K. Klein & G. Murphy, 2001). The authors investigated this issue using the methods of D. K. Klein and G. Murphy (2001), in whose study participants judged whether ambiguous words embedded in word pairs (e.g., tasty chicken) made sense as a function of a cooperating, conflicting, or neutral context. The ambiguous words were independently rated as having low, moderate, or highly overlapping senses to approximate a continuum from homonymy to metonymic polysemy. The effects of meaning dominance were examined. Words with highly overlapping meanings (e.g., metonymy) showed reduced effects of context and dominance compared with words with moderately or low overlapping meanings (e.g., metaphorical polysemy and homonymy). These results suggest that the comprehension of ambiguous words is mediated by the semantic overlap of alternative senses/meanings.     

Using E-Z Reader to examine the concurrent development of eye-movement control and reading skill

Compared to skilled adult readers, children typically make more fixations that are longer in duration, shorter saccades, and more regressions, thus reading more slowly (Blythe & Joseph, 2011). Recent attempts to understand the reasons for these differences have discovered some similarities (e.g., children and adults target their saccades similarly; Joseph, Liversedge, Blythe, White, & Rayner, 2009) and some differences (e.g., children’s fixation durations are more affected by lexical variables; Blythe, Liversedge, Joseph, White, & Rayner, 2009) that have yet to be explained. In this article, the E-Z Reader model of eye-movement control in reading (Reichle, 2011 and Reichle et al., 1998) is used to simulate various eye-movement phenomena in adults vs. children in order to evaluate hypotheses about the concurrent development of reading skill and eye-movement behavior. These simulations suggest that the primary difference between children and adults is their rate of lexical processing, and that different rates of (post-lexical) language processing may also contribute to some phenomena (e.g., children’s slower detection of semantic anomalies; Joseph et al., 2008). The theoretical implications of this hypothesis are discussed, including possible alternative accounts of these developmental changes, how reading skill and eye movements change across the entire lifespan (e.g., college-aged vs. older readers), and individual differences in reading ability.     

Distributional analysis of semantic interference in picture naming

In picture–word interference experiments, participants name pictures (e.g., of a cat) while trying to ignore distractor words. Mean response time (RT) is typically longer with semantically related distractor words (e.g., dog) than with unrelated words (e.g., shoe), called semantic interference. Previous research has examined the RT distributional characteristics of distractor effects by performing ex-Gaussian analyses, which reveal whether effects are present in the normal part of the distribution (the μ parameter), its long right tail (the τ parameter), or both. One previous study linked the semantic interference effect selectively to the distribution tail. In the present study, we replicated the semantic interference effect in the mean picture naming RTs. Distributional analysis of the RTs and those of a previous study revealed that semantic interference was present in both μ and τ. These results provide evidence that the effect is not selectively linked to the τ parameter, and they warn against any simple one-to-one mapping between semantic interference and distributional parameters.     

The sound of enemies and friends in the neighborhood

Previous studies (e.g., Pecher, Zeelenberg, & Wagenmakers, 2005) found that semantic classification performance is better for target words with orthographic neighbors that are mostly from the same semantic class (e.g., living) compared to target words with orthographic neighbors that are mostly from the opposite semantic class (e.g., nonliving). In the present study we investigated the contribution of phonology to orthographic neighborhood effects by comparing effects of phonologically congruent orthographic neighbors (book-hook) to phonologically incongruent orthographic neighbors (sand-wand). The prior presentation of a semantically congruent word produced larger effects on subsequent animacy decisions when the previously presented word was a phonologically congruent neighbor than when it was a phonologically incongruent neighbor. In a second experiment, performance differences between target words with versus without semantically congruent orthographic neighbors were larger if the orthographic neighbors were also phonologically congruent. These results support models of visual word recognition that assume an important role for phonology in cascaded access to meaning.     

When Stronger Knowledge Slows You Down: Semantic Relatedness Predicts Children's Co‐Activation of Related Items in a Visual Search Paradigm

A large literature suggests that the organization of words in semantic memory, reflecting meaningful relations among words and the concepts to which they refer, supports many cognitive processes, including memory encoding and retrieval, word learning, and inferential reasoning. The co‐activation of related items has been proposed as a mechanism by which semantic knowledge influences cognition, and contemporary accounts of semantic knowledge propose that this co‐activation is graded—that it depends on how strongly related the items are in semantic memory. Prior research with adults yielded evidence supporting this prediction; however, there is currently no evidence of graded co‐activation early in development. This study provides the first evidence that in children the co‐activation of related items depends on their relational strength in semantic memory. Participants (N = 84, age range: 3–9 years) were asked to identify a target (e.g., bone) amid distractors. Children's responses were slowed down by the presence of a related distractor (e.g., puppy) relative to unrelated distractors (e.g., flower)—suggesting that children co‐activated related items upon hearing the name of the target. Importantly, the degree of this co‐activation was predicted by the strength of the target–distractor relation, such that distractors more strongly related to the targets slowed down children to a larger extent. These findings have important implications for understanding how organized semantic knowledge affects other cognitive processes across development.     

Is Passive Syntax Semantically Constrained? Evidence From Adult Grammaticality Judgment and Comprehension Studies

To explain the phenomenon that certain English verbs resist passivization (e.g., *£5 was cost by the book), Pinker (1989) proposed a semantic constraint on the passive in the adult grammar: The greater the extent to which a verb denotes an action where a patient is affected or acted upon, the greater the extent to which it is compatible with the passive. However, a number of comprehension and production priming studies have cast doubt upon this claim, finding no difference between highly affecting agent‐patient/theme‐experiencer passives (e.g., Wendy was kicked/frightened by Bob) and non‐actional experiencer theme passives (e.g., Wendy was heard by Bob). The present study provides evidence that a semantic constraint is psychologically real, and is readily observed when more fine‐grained independent and dependent measures are used (i.e., participant ratings of verb semantics, graded grammaticality judgments, and reaction time in a forced‐choice picture‐matching comprehension task). We conclude that a semantic constraint on the passive must be incorporated into accounts of the adult grammar.     

Conceptual similarity effects on working memory in sentence contexts: Testing a theory of anaphora

The degree of semantic similarity between an anaphoric noun phrase (e.g., the bird) and its antecedent (e.g., a robin) is known to affect the anaphor resolution process, but the mechanisms that underlie this effect are not known. One proposal (Almor, 1999) is that semantic similarity triggers interference effects in working memory and makes two crucial assumptions: First, semantic similarity impairs working memory just as phonological similarity does (e.g., Baddeley, 1992), and, second, this impairment interferes with processes of sentence comprehension. We tested these assumptions in two experiments that compared recall accuracy between phonologically similar, semantically similar, and control words in sentence contexts. Our results do not provide support for Almor's claims: Phonological overlap decreased recall accuracy in sentence contexts, but semantic similarity did not. These results shed doubt on the idea that semantic interference in working memory is an underlying mechanism in anaphor resolution.     

Decomposing animacy reversals between agents and experiencers: An ERP study

The present study aimed to refine current hypotheses regarding thematic reversal anomalies, which have been found to elicit either N400 or - more frequently - “semantic-P600” (sP600) effects. Our goal was to investigate whether distinct ERP profiles reflect aspectual-thematic differences between Agent-Subject Verbs (ASVs; e.g., ‘to eat’) and Experiencer-Subject Verbs (ESVs; e.g., ‘to love’) in English. Inanimate subject noun phrases created reversal anomalies on both ASV and ESV. Animacy-based prominence effects and semantic association were controlled to minimize their contribution to any ERP effects. An N400 was elicited by the target verb in the ESV but not the ASV anomalies, supporting the hypothesis of a distinctive aspectual-thematic structure between ESV and ASV. Moreover, the N400 finding for English ESV shows that, in contrast to previous claims, the presence versus absence of N400s for this kind of anomaly cannot be exclusively explained in terms of typological differences across languages.     

The broth in my brother’s brothel: Morpho-orthographic segmentation in visual word recognition

Much research suggests that words comprising more than one morpheme are represented in a “decomposed” manner in the visual word recognition system. In the research presented here, we investigate what information is used to segment a word into its morphemic constituents and, in particular, whether semantic information plays a role in that segmentation. Participants made visual lexical decisions to stem targets preceded by masked primes sharing (1) a semantically transparent morphological relationship with the target (e.g.,cleaner-CLEAN), (2) an apparent morphological relationship but no semantic relationship with the target (e.g.,corner-CORN), and (3) a nonmorphological form relationship with the target (e.g.,brothel-BROTH). Results showed significant and equivalent masked priming effects in cases in which primes and targets appeared to be morphologically related, and priming in these conditions could be distinguished from nonmorphological form priming. We argue that these findings suggest a level of representation at which apparently complex words are decomposed on the basis of their morpho-orthographic properties. Implications of these findings for computational models of reading are discussed.     

Word association in early Alzheimer’s disease

The hypothesis that Alzheimer’s disease (AD) degrades semantic representations predicts that AD qualitatively alters spontaneous thoughts. In two experiments contrasting free associations to words with strong (e.g., bride-groom) versus weak (e.g., body-leg) associates participants with AD produced less common responses (e.g., bride-pretty) than normal controls but only for words with strong associations, and only on the first (but not on second or third) association response. Furthermore, all participants produced fewer semantically related responses to words with weak associates. Because strong associations should be retrieved more easily than weak associations these results are problematic for retrieval-based accounts of AD. Instead we propose that AD entails a semantic deficit, and that strong associations involve more semantic processing than weak associations (in all speakers).     

Differential impacts of age of acquisition on letter and semantic fluency in Alzheimer's disease patients and healthy older adults

The degree to which the typical age of acquisition (AoA) of words and word frequency have separable influences on verbal production tasks has been strongly debated. To examine the overlap between these factors in verbal fluency tasks, the performance of Alzheimer's disease (AD) patients (N?=?34) and normal elderly controls (N?=?36) was compared on semantic (e.g., vegetables) and letter (e.g., words that begin with F) fluency tasks. These comparisons revealed that words generated for the semantic fluency task had an earlier AoA while words generated for the letter fluency task had a higher word frequency. Differences in AoA between AD patients and controls were larger for semantic than letter fluency. These results suggest that AoA has an effect on verbal production that is independent of word frequency and that AoA has a semantic locus.     

Differential prefrontal–temporal neural correlates of semantic processing in children

This study used functional magnetic resonance imaging (fMRI) to examine brain–behavior correlations in a group of 16 children (9- to 12-year-olds). Activation was measured during a semantic judgment task presented in either the visual or auditory modality that required the individual to determine whether a final word was related in meaning to one of two previous words (e.g., found–tank–lost). The main finding was that higher performers (i.e., accuracy) were associated with more activation in posterior representational systems including the inferior and middle temporal gyri, whereas lower performers were associated with more activation in anterior regions including the inferior and middle frontal gyri. This pattern of results was interpreted as reflecting an elaborated semantic representational system in temporal areas for the high accuracy performers that allowed them to efficiently and accurately make meaning based judgments. The low accuracy performers may have an inaccurate or weakly interconnected semantic system that results in greater use of frontal areas in a feature selection process.     

Anterior temporal cortex and semantic memory: Reconciling findings from neuropsychology and functional imaging

Studies of semantic impairment arising from brain disease suggest that the anterior temporal lobes are critical for semantic abilities in humans; yet activation of these regions is rarely reported in functional imaging studies of healthy controls performing semantic tasks. Here, we combined neuropsychological and PE T functional imaging data to show that when healthy subjects identify concepts at a specific level, the regions activated correspond to the site of maximal atrophy in patients with relatively pure semantic impairment. The stimuli were color photographs of common animals or vehicles, and the task was category verification at specific (e.g., robin), intermediate (e.g., bird), or general (e.g., animal) levels. Specific, relative to general, categorization activated the antero-lateral temporal cortices bilaterally, despite matching of these experimental conditions for difficulty. Critically, in patients with atrophy in precisely these areas, the most pronounced deficit was in the retrieval of specific semantic information.     

Predicting raters’ transparency judgments of English and Chinese morphological constituents using latent semantic analysis

The morphological constituents of English compounds (e.g., “butter” and “fly” for “butterfly”) and two-character Chinese compounds may differ in meaning from the whole word. Subjective differences and ambiguity of transparency make judgments difficult, and a computational alternative based on a general model might be a way to average across subjective differences. In the present study, we propose two approaches based on latent semantic analysis (Landauer & Dumais in Psychological Review 104:211–240, 1997): Model 1 compares the semantic similarity between a compound word and each of its constituents, and Model 2 derives the dominant meaning of a constituent from a clustering analysis of morphological family members (e.g., “butterfingers” or “buttermilk” for “butter”). The proposed models successfully predicted participants’ transparency ratings, and we recommend that experimenters use Model 1 for English compounds and Model 2 for Chinese compounds, on the basis of differences in raters’ morphological processing in the different writing systems. The dominance of lexical meaning, semantic transparency, and the average similarity between all pairs within a morphological family are provided, and practical applications for future studies are discussed.     

Age-related differences in interlingual priming: a behavioural and electrophysiological investigation

Reaction time (RT) and the N400 ERP component were measured to examine age-related differences in bilingual language processing. Although young bilinguals appear to access both languages simultaneously (i.e., non-selective access), little is known about language selection in older adults. The effect of language context on language selectivity was investigated using interlingual homographs (IH; i.e., words with identical orthography but distinct semantic features in two languages, e.g., coin meaning 'corner' in French and 'money' in English). Younger and older French/English bilinguals were presented with triplets of letter strings comprised of a language context cue, an IH, and a target word, in a lexical decision semantic priming task. RT and ERP results support non-selective language access in young adults; however, the older bilinguals used the language context cue to bias their reading of the IH. Results are discussed in terms of age-related changes in language processing and context use in bilinguals.     

The Gaussian Graphical Model in Cross-Sectional and Time-Series Data

We discuss the Gaussian graphical model (GGM; an undirected network of partial correlation coefficients) and detail its utility as an exploratory data analysis tool. The GGM shows which variables predict one-another, allows for sparse modeling of covariance structures, and may highlight potential causal relationships between observed variables. We describe the utility in three kinds of psychological data sets: data sets in which consecutive cases are assumed independent (e.g., cross-sectional data), temporally ordered data sets (e.g., n = 1 time series), and a mixture of the 2 (e.g., n > 1 time series). In time-series analysis, the GGM can be used to model the residual structure of a vector-autoregression analysis (VAR), also termed graphical VAR. Two network models can then be obtained: a temporal network and a contemporaneous network. When analyzing data from multiple subjects, a GGM can also be formed on the covariance structure of stationary means—the between-subjects network. We discuss the interpretation of these models and propose estimation methods to obtain these networks, which we implement in the R packages graphicalVAR and mlVAR. The methods are showcased in two empirical examples, and simulation studies on these methods are included in the supplementary materials.