Cognitive psychology: core concepts and applications

¶ … Phonological and conceptual activation in speech comprehension

This article focuses on the process of understanding as it relates to separate lexical representations of sound and meaning. The phonological and conceptual representations in language have been separated, as comprehension are connected to these different concepts separately. In explaining these concepts, the article distinguishes between word representation in the mental lexicon and the lexical candidates for recognizing utterances.

When the hearer is the presented with running speech with few clear cues to word boundaries, a mechanism is needed to determine the best sequence in terms of the input. In this way the correct utterance is determined by competition. The activation concept is addressed via a number of divisions in the text. Firstly, activation testing involves the cross-modal priming task. Lexical activation is then determined by presenting the hearer with an aural phonetic prime word, and following with a visual target word, after which the relationship between the two is determined. In the context of sentences however, priming is neither obvious nor as reliable as in the simple word pairs of associative priming. The effect of this phenomenon upon sound and meaning comprehension is examined by a number of experiments discussed in the document. The conclusion is that a single level of representation is not enough to explicate spoken language comprehension. Processing occurs at a number of different levels of representation.

Article 2: The activation of offset-embedded words: Evidence from eye-tracking and identity priming.

The article addresses the problem of understanding the flow of speech in the face of embedded words often occurring in polysyllabic English words. The phenomenon of competition is once again addressed in its capacity to activate the accurate meaning associations of these words. As the utterance becomes increasingly clear, the possible meanings of polysyllabic words gradually out compete each other for dominance. The document cites several studies done to determine the nature of the connection between competition and comprehension of polysyllabic words and embedded monosyllabic words. The goal is identified as investigating the activation of offset-embedded words and the role of find-grained acoustic detail in the comprehension process. The central problem addressed by the study is the fact that studies relating to offset-embedded words have been contradictory in their results. The authors identify the solution to the problem as one of generalization. The suggestion is that offset-embedded words are indeed activated, but the question should rather focus on which specific conditions and factors are required for this to occur. While the embedded word's lexical connotation can therefore be activated in competition with the longer word, but this does not necessarily occur.

Article 3: The role of prosodic boundaries in the resolution of lexical embedding in speech comprehension.

The problem addressed by this article focuses on onset-embedded words and the way in which they present problems in word recognition. The research presented in the document attempts to reconcile embedding and instrumentality in spoken-word recognition. The premise is that spoken words are recognized incrementally as their associated sounds become available. When longer words however begin with a strong onset-embedded word, this may impair the comprehension process of the specific word as well as the utterances following the word. The basis of this is that the recognition process is slowed down by this phenomenon. The issue is further complicated when the embedded and longer word are part of a sequence that is fully ambiguous. The solution is the proposed existence of fine-grained, in-speech information in the utterance that listeners may use to disambiguate expressions containing onset-embedded words, and competition is resolved satisfactorily. Several such fine-grained elements are discussed in the article, including syllable match and fine-grained acoustic cues, by which ambiguities may be resolved. Different acoustic cues may for example occur in monosyllabic and polysyllabic words, even if the latter is initially identical to the former. In this, the prosodic possibilities of a sentence with onset-embedded monosyllabic words are investigated by means of the context and morphosyntactic structure of a sentence. In other words, there is a constraint of prosodic possibilities open to the speaker when presenting the hearer with ambiguous utterances. The findings of experiments in this regard indicate that the sub-phonemic acoustic cues associated with monosyllabic words, for example segmental lengthening, can be used to disambiguate lexical interpretation of a spoken utterance. The hearer therefore uses a variety of fine-grained clues, as proposed in the beginning of the article, to enhance his or her comprehension of a spoken utterance.

Article 4: Electrophysiological evidence for early contextual influences during spoken-word recognition

The study depicted in this document focuses more on the physiologically cognitive basis of spoken-word recognition than the specific workings of the phenomenon itself. The aim is to determine the electrophysiological manifestation of contextual effects on spoken-word recognition. As such, the aim is further to validate early electrophysiological manifestation in terms of the interface between words and their context. As a component of event-related potentials (ERPs) is the N400, a negative-going component that denotes the semantic processing of a word. The N400 component is larger for words recognized to be incongruent in the context of their surrounding utterances. N400 however only denotes semantic integration, which is the final process of word recognition. One of the aims of the study is then to study the N400 process to determine whether there are prior processes related to the entire word-recognition sequence prior to integration. This study has been preceded by several other studies involving N400, with differing results and interpretations. One of these is the phonological expectation in terms of preceding context. This is identified as the early N400 effect. Another study concluded that a semantic expectation was formed. While the results contrast, both findings indicate processes that precede the final integration indicated by the N400 component. While the study in the document did indeed identify an early negativity, this did not substantiate the hypothesis of phonetic expectation. The conclusion is that bottom-up information received by acoustic processing influences word integration before top-down information has an effect.

Article 5: The cascaded nature of lexical selection and integration in auditory sentence processing.

The study addresses the question of whether lexical selection and semantic word integration into its preceding context can be separated or are parallel. The document cites studies indicating the constraining and simplifying effect of context upon word selection and recognition: possible meanings are reduced and the time to identify the word is concomitantly shortened. The finding, after a number of experiments involving the N400 component, indicates a cascading effect: semantic word integration and lexical selection tend to be parallel rather than separate processes. This also substantiates the favor assigned to the bottom-up approach, as seen in the previous article. The idea of integration in terms of previous context is furthermore emphasized by the study. The authors also emphasize that speech is a very rapid phenomenon, and as such there is no time for full recognition before word selection. As such, words that are incongruent in the preceding context are sometimes selected due to time constraints, and these would then have to be repeated to be fully understood.