Lee H. Wurm

Tone perception in Cantonese and Mandarin: A cross-linguistic comparison

This study investigated the effects of linguistic experience on tone perception. Both Cantonese (in Experiment 1) and Mandarin (in Experiment 2) tones, including both lexical and nonlexical tones, were presented to three groups of subjects: Cantonese, Mandarin, and English native speakers. Subjects were asked to determine whether two auditorily presented tones were the same or different. The interval between the presentation of the two tones, and the level of interference during this interval, were manipulated. Native speakers did better at discriminating tones from their own languages than the other two groups of subjects, for both lexical and nonlexical tones. Subjects did worst when they were required to count backward during the interstimulus interval. Cantonese speakers were better than both Mandarin and English speakers at discriminating Cantonese tones, and there was no difference between Mandarin and English speakers, except in one condition. Mandarin speakers did better than both Cantonese and English speakers, and Cantonese speakers did better than English speakers, at discriminating Mandarin tones. Results are discussed in terms of the effects of language background, differences between Cantonese and Mandarin tones, and the nature of encoding in short-term memory.

Performance in auditory and visual emotional stroop tasks: a comparison of older and younger adults.

Research has shown age-related declines in the cognitive ability to inhibit irrelevant information. Thirty-six younger adults (mean age = 22 years) and 36 older adults (mean age = 74 years) performed 2 versions of an emotional Stroop task. In one, they made lexical decisions to emotion words spoken in 1 of several tones of voice. Latencies were longer for test words spoken in an incongruent tone of voice, but only for older adults. In another, words were displayed on a computer screen in a colored font, and participants quickly named the font color. Latencies were longer for test words high on arousal, but only for older adults. Results are discussed in terms of inhibitory cognitive processes, attention, and theories of emotional development.

Psychophysics of reading. XI. Comparing color contrast and luminance contrast

Text can be depicted by luminance contrast (i.e., differences in luminance between characters and background) or by color contrast (i.e., differences in chromaticity). We used a psychophysical method to measure the reading speeds of eight normal and ten low-vision subjects for text displayed on a color monitor. Reading speed was measured as a function of luminance contrast, color contrast (derived from mixtures of red and green), and combinations of the two. When color contrast is high, normal subjects can read as rapidly as with high luminance contrast (greater than 300 words/min). Curves of reading speed versus contrast have the same shape for the two forms of contrast and are superimposed when contrast is measured in multiples of a threshold value. When both color and luminance contrast are present, there is no sign of additive interaction, and performance is determined by the form of contrast yielding the highest reading rate. Our findings suggest that color contrast and luminance contrast are coded in similar ways in the visual system but that the neural signals used in letter recognition are carried by different pathways for color and luminance. We found no advantages of color contrast for low-vision reading. For text composed of 6 degrees characters, all low-vision subjects read better with luminance contrast than with color contrast.

Prosodic cues for morphological complexity in Dutch and English

Previous work has shown that Dutch listeners use prosodic information in the speech signal to optimise morphological processing: Listeners are sensitive to prosodic differences between a noun stem realised in isolation and a noun stem realised as part of a plural form (in which the stem is followed by an unstressed syllable). The present study, employing a lexical decision task, provides an additional demonstration of listeners’ sensitivity to prosodic cues in the stem. This sensitivity is shown for two languages that differ in morphological productivity: Dutch and English. The degree of morphological productivity does not correlate with listeners’ sensitivity to prosodic cues in the stem, but it is reflected in differential sensitivities to the word-specific log odds ratio of encountering an unshortened stem (i.e., a stem in isolation) versus encountering a shortened stem (i.e., a stem followed by a suffix consisting of one or more unstressed syllables). In addition to being sensitive to the prosodic cues themselves, listeners are also sensitive to the probabilities of occurrence of these prosodic cues.

Speech perception and vocal expression of emotion

Two experiments using identical stimuli were run to determine whether the vocal expression of emotion affects the speed with which listeners can identify emotion words. Sentences were spoken in an emotional tone of voice (Happy, Disgusted, or Petrified), or in a Neutral tone of voice. Participants made speeded lexical decisions about the word or pseudoword in sentence-final position. Critical stimuli were emotion words that were either semantically congruent or incongruent with the tone of voice of the sentence. Experiment 1, with randomised presentation of tone of voice, showed no effect of congruence or incongruence. Experiment 2, with blocked presentation of tone of voice, did show such effects: Reaction times for congruent trials were faster than those for baseline trials and incongruent trials. Results are discussed in terms of expectation (e.g., Kitayama, 1990, 1991, 1996) and emotional connotation, and implications for models of word recognition are considered.

Danger and usefulness: An alternative framework for understanding rapid evaluation effects in perception?

Previous studies have shown effects of rated danger and usefulness on lexical access. All of them have used stimuli selected for connotations of danger and/or usefulness. Stimuli for the present lexical decision study were all of the nouns, verbs, and adjectives from the Balota et al. (2002) English Lexicon Project (subject to constraints relating to experimental control; none had anything to do with danger or usefulness). The interaction between danger and usefulness ratings previously demonstrated (Wurm & Vakoch, 2000; Wurm, Vakoch, Seaman, & Buchanan, 2004; Wurm, Whitman, Seaman, Hill, & Ulstad, 2007) was found for nouns, even when age of acquisition was controlled. It was also found for verbs and adjectives. The interaction is believed to reflect competing pressures to (1) avoid dangerous objects/events and (2) approach valuable resources. It may be a manifestation of the rapid evaluation effects pervasive in the literature. Post hoc analyses showed that danger and usefulness explain as much variance as valence and arousal, or evaluation, potency, and activity.

Dimensions of Speech Perception: Semantic Associations in the Affective Lexicon

The affective lexicon has been explained in terms of three underlying dimensions: Evaluation, Activity, and Potency. We assessed the importance of these dimensions during online speech perception. Participants made speeded lexical decisions about emotion words that were heard in a tone of voice that was either congruent or incongruent with the words meaning. The denotative semantic category from which words were chosen was significantly related to lexical decision times (P < 0.001). Tone of voice did not influence decision times, nor did it interact with semantic category. Regression analyses showed that lexical decision times were significantly predicted by dimension weights on Potency, and by the three-way interaction between dimension weights on Evaluation, Activity, and Potency (both P s < 0.001). The implications of this study for models of knowledge representation and perception are discussed.

Recognition of Spoken Words: Semantic Effects in Lexical Access.

Until recently most models of word recognition have assumed that semantic effects come into play only after the identification of the word in question. What little evidence exists for early semantic effects in word recognition has relied primarily on priming manipulations using the lexical decision task, and has used visual stimulus presentation. The current study uses auditory stimulus presentation and multiple experimental tasks, and does not use priming. Response latencies for 100 common nouns were found to depend on perceptual dimensions identified by Osgood (1969): Evaluation, Potency, and Activity. In addition, the two-way interactions between these dimensions were significant. All effects were above and beyond the effects of concreteness, word length, frequency, onset phoneme characteristics, stress, and neighborhood density. Results are discussed against evidence from several areas of research suggesting a role of behaviorally important information in perception.

The Adaptive Value of Lexical Connotation in Speech Perception

Previous work (e.g. Bargh, Chaiken, Govender, & Pratto, 1992; Fazio, Sanbonmatsu, Powell, & Kardes, 1986) has shown that objects are evaluated on a goodness/badness dimension automatically and preconsciously. Vakoch and Wurm (1997; Wurm & Vakoch, 1996) have found similar results using different stimuli and tasks. They found that auditory lexical decision times depend on dimensions of connotation (Evaluation, Potency, and Activity). Reaction times (RTs) from these studies were interpreted in terms of the evolutionary adaptiveness of different types of perceptual processing. The current study introduces a new way to define words, using two dimensions (Danger and Usefulness) rather than three, that allows a direct test of the adaptiveness model. RTs for nouns chosen for their adaptive significance were related to Usefulness and Danger, and to the interaction between Usefulness and Danger. A database of dimension weights is included.

Emotional Connotation in Speech Perception: Semantic Associations in the General Lexicon

Lexical access of emotion words has been shown to depend on three underlying dimensions (Evaluation, Activity, and Potency). The importance of these dimensions of emotional connotation was assessed during on-line speech perception of words drawn from the general lexicon. Lexical decision times were significantly predicted by main effects of Evaluation and Potency, as well as by an Evaluation Activity interaction and an Evaluation Potency interaction. An evolutionary account is proposed to explain the differential processing of words in the general and affective lexica. Whereas the affective lexicon seems to be structured to avoid threats to the individual, the general lexicon appears to be designed for obtaining scarce but valuable resources.