Contrasting effects of age of acquisition and word frequency on auditory and visual lexical decision

In four experiments, we examined the effects of frequency and age of acquisition on auditory and visual lexical decision. Word frequency affected visual, but not auditory, lexical decision speed (Experiments 1 and 3). Age of acquisition affected lexical decision speed in both modalities (Experiments 2 and 4). We suggest that previous reports of effects of frequency on auditory lexical decision may be due to a confounding of frequency with age of acquisition, and we discuss the implications of these findings for theories of auditory and visual word recognition.     

Aversive aspects of a schedule of positive reinforcement

Six male White Carneaux pigeons were trained to peck at one of two keys to obtain food on several fixed-ratio schedules of reinforcement. Concurrently, the first response on a second key could, I—change the conditions of visual stimulation and remove the food reinforcement contingency, II—change the conditions of stimulation and have no effect upon the reinforcement contingency, or III—do nothing. The second response on the stimulus change key always restored baseline conditions. When second-key responses produced a stimulus change, the number of such responses was a function of the ratio value on the first key. Typically, second-key responses occurred before the start of fixed-ratio runs. The duration of stimulus change periods was an exponential function of the number of responses required for reinforcement when the possibility for reinforcement was not disturbed by periods of stimulus change (Condition II).     

CCTV on trial: Matching video images with the defendant in the dock

The experiments reported in this paper investigated simultaneous identity matching of unfamiliar people physically present in person with moving video images typical of that captured by closed circuit television (CCTV). This simulates the decision faced by a jury in court when the identity of somebody caught on CCTV is disputed. Namely, ‘is the defendant in the dock the person depicted in video’? In Experiment 1, the videos depicted medium‐range views of a number of actor ‘culprits’. Experiment 2 used similar quality images taken a year previously, some of which showed the culprits in disguise. Experiment 3 utilised high‐quality close‐up video images. It was consistently found that in both culprit‐present and culprit‐absent videos and in optimal conditions, matching the identity of a person in video can be highly susceptible to error. Copyright © 2008 John Wiley & Sons, Ltd.     

Mortality salience and prejudice towards ethno-religion minorities: Results and implications of a Nigerian study

The present study examined mortality salience (MS) effect on prejudice towards an ethno-religion minority group of Northern Nigeria. Participants were 120 undergraduate students (females = 41.67%) with an age range between 17 and 38 years. The students completed a Distance-(relationship)-Situation (DS) measure under alternative conditions: with MS priming and a control condition. Following a three-way mixed model ANOVA, results showed MS to predict prejudice across relationship situations of secret disclosure, business partnership, and cooperating to get a task done. Consistent with terror management theory, MS effects on ethno-cultural prejudice expression apply across relationship situations.     

The effects of inventory on vowel perception in French and Spanish: an MEG study

Production studies have shown that speakers of languages with larger phoneme inventories expand their acoustic space relative to languages with smaller inventories [Bradlow, A. (1995). A comparative acoustic study of English and Spanish vowels. Journal of the Acoustical Society of America, 97(3), 1916-1924; Jongman, A., Fourakis, M., & Sereno, J. (1989). The acoustic vowel space of Modern Greek and German. Language Speech, 32, 221-248]. In this study, we investigated whether this acoustic expansion in production has a perceptual correlate, that is, whether the perceived distance between pairs of sounds separated by equal acoustic distances varies as a function of inventory size or organization. We used magnetoencephalography, specifically the mismatch field response (MMF), and compared two language groups, French and Spanish, whose vowel inventories differ in size and organization. Our results show that the MMF is sensitive to inventory size but not organization, suggesting that speakers of languages with larger inventories perceive the same sounds as less similar than speakers with smaller inventories.     

The categorical structure of knowledge for famous people (and a novel application of Centre-Surround theory)

Knowledge of familiar people is essential to guide social interaction, yet there is uncertainty about whether semantic knowledge for people is stored in a categorical structure as for objects. Four priming experiments using hard-to-perceive primes investigated whether occupation forms a category connecting famous persons in semantic memory. Primes were famous faces exposed for 17ms with masking, resulting in severely restricted awareness and thus precluding expectancy-based priming effects. Targets were consciously perceptible famous faces (Experiments 1-3), famous names (Experiment 3), or occupations (Experiment 4) representing either the same or different occupation to the prime. Significant priming demonstrated the operation of automatic processes, including spreading activation, among persons sharing a common occupation; this supports the categorical view. The direction of priming (faster/slower responses to same-occupation than different-occupation targets) was dependent on prime-target stimulus onset asynchrony (Experiments 1-3) and type of target (Experiment 4). This pattern of results is attributed to the Centre-Surround mechanism proposed by Carr and Dagenbach [Carr, T. H., & Dagenbach, D. (1990). Semantic priming and repetition priming from masked words: evidence for a centre-surround attentional mechanism in perceptual recognition. Journal of Experimental Psychology: Learning, Memory and Cognition, 16, 341-350]. These results support (a) the categorical structure of semantic knowledge for famous people and (b) the application of the Centre-Surround mechanism to the domain of person recognition.     

The effects of the age of eyewitnesses on the accuracy and suggestibility of their testimony

Previous studies have compared the performance of young adult eyewitnesses with that of children or elderly eyewitnesses, but few studies have allowed direct comparison of the performance of all three age groups. The accuracy and suggestibility of accounts of a video recording of a kidnapping were investigated using an experimental eyewitness paradigm. Subjects were drawn from three age groups: children (aged 7–9 years); young adults (aged 16–18 years) and elderly subjects (aged 60–85 years). Subjects' accuracy in answering non-misleading questions and their susceptibility to misleading information was measured. Both the elderly and child subjects gave fewer correct answers and more incorrect answers to non-misleading questions than did young adults. The elderly subjects gave fewer correct responses but also fewer incorrect responses to non-misleading questions than did child subjects. Children were more suggestible than either elderly or young adults. No significant difference was found in the suggestibility of elderly and young adults. Contrary to the trace strength hypothesis no relationship was found between accuracy of recall and suggestibility. © 1997 John Wiley & Sons, Ltd.