Psychology

Project rationale • Participant profile • Methodology • Two experiments 1. Which vehicle is travelling faster? 2. Would you have time to cross the road? Project Rationale • Road traffic accidents are the third leading cause of death for children 5-9 years • Evidence of deficits in detecting visual motion in 'clumsy' children • Deficits in perceptual acuity could have serious implications at the roadside!

Almost all locomotor animals respond to visual looming or to discrete changes in optical size. The need to detect and process looming remains critically important for humans in everyday life. Road traffic statistics confirm that children up to 15 years old are overrepresented in pedestrian casualties. We demonstrate that, for a given pedestrian crossing time, vehicles traveling faster loom less than slower vehicles, which creates a dangerous illusion in which faster vehicles may be perceived as not approaching. Our results from perceptual tests of looming thresholds show strong developmental trends in sensitivity, such that children may not be able to detect vehicles approaching at speeds in excess of 20 mph. This creates a risk of injudicious road crossing in urban settings when traffic speeds are higher than 20 mph. The risk is exacerbated because vehicles moving faster than this speed are more likely to result in pedestrian fatalities.

Cross-examination is thought by some to be the main safeguarding process in an adversarial trial but it is often used as an opportunity to discredit witnesses. For example, the use of complex language  can confuse witnesses, particularly those who are young and vulnerable, exposing errors and inconsistencies in their statement that may not exist. To put individuals at ease before a court appearance the courts in England and Wales allow witnesses to review a copy of their original testimony. The idea is to refresh their memory before cross-examination. Whilst this option is available it is not always offered therefore, if ‘refreshing’ is beneficial to memory, some witnesses may be at a disadvantage in the courtroom. This presentation will discuss what it means to ‘refresh’ memory and will describe a study which aims to assess the effect of this process on the accuracy and consistency of a witness’ memory during cross-examination. Participants experienced a live event, and were interviewed following Achieving Best Evidence guidelines, and later cross-examined. Prior to cross-examination, half the participants were shown a video-recording of their original interview (refreshing condition) and half were shown an unrelated video (control condition).  The results of this study will be discussed.

Visual word identification requires readers to code the identity and order of the letters in a word and match this code against previously learned codes. Current models of this lexical matching process posit context-specific letter codes in which letter representations are tied to either specific serial positions or specific local contexts (e.g., letter clusters). The spatial coding model described here adopts a different approach to letter position coding and lexical matching based on context-independent letter representations. In this model, letter position is coded dynamically, with a scheme called spatial coding. Lexical matching is achieved via a method called superposition matching, in which input codes and learned codes are matched on the basis of the relative positions of their common letters. Simulations of the model illustrate its ability to explain a broad range of results from the masked form priming literature, as well as to capture benchmark findings from the unprimed lexical decision task.

This article describes a Windows program that enables users to obtain a broad range of statistics concerning the properties of word and nonword stimuli, including measures of word frequency, orthographic similarity, orthographic and phonological structure, age of acquisition, and imageability. It is designed for use by researchers in psycholinguistics, particularly those concerned with recognition of isolated words. The program computes measures of orthographic similarity on line, either with respect to a default vocabulary of 30,605 words or to a vocabulary specified by the user. In addition to providing standard orthographic neighborhood measures, the program can be used to obtain information about other forms of orthographic similarity, such as transposed-letter similarity and embedded-word similarity. It is available, free of charge, from the following Web site

Predictions derived from the interactive activation (IA) model were tested in 3 experiments using the masked priming technique in the lexical decision task. Experiment 1 showed a strong effect of prime lexicality: Classifications of target words were facilitated by orthographically related nonword primes (relative to unrelated nonword primes) but were inhibited by orthographically related word primes (relative to unrelated word primes). Experiment 2 confirmed IA's prediction that inhibitory priming effects are greater when the prime and target share a neighbor. Experiment 3 showed a minimal effect of target word neighborhood size (N) on inhibitory priming but a trend toward greater inhibition when nonword foils were high-N than when they were low-N. Simulations of 3 different versions of the IA model showed that the best fit to the data is produced when lexical inhibition is selective and when masking leads to reset of letter activities.

Five theories of how letter position is coded are contrasted: position-specific slot-coding, Wickelcoding, open-bigram coding (discrete and continuous), and spatial coding. These theories make different predictions regarding the relative similarity of three different types of pairs of letter strings: substitution neighbors, neighbors-once-removed, and double-substitution neighbors. In Experiment 1, we used an illusory word paradigm and found that neighbor-once-removed similarity contexts resulted in fewer illusory word reports than substitution neighbors but more illusory words than double-substitution neighbors. In Experiments 2 and 3, we used a masked form priming technique with a lexical-decision task. The pattern of facilitation was as predicted by spatial coding but was incompatible with slot-coding, Wickelcoding, and both versions of open-bigram coding. These results provide further support for the SOLAR (self-organizing lexical aquisition and recognition) model of visual word identification.

Participants semantically categorized target words that contain subsets (Experiment 1; e.g., target = hatch, subset = hat) or that are parts of supersets (Experiment 2; e.g., target = bee, superset = beer). In both experiments, the targets were categorized in a congruent condition (in which the subset-superset was associated with the same response, e.g., Does hatch refer to a human body part?) and an incongruent condition (in which the subset-superset was associated with a conflicting response, e.g., Does hatch refer to a piece of clothing?). Responses were slower and less accurate in the incongruent conditions, suggesting that subsets and supersets were processed to the level of meaning. Congruency effects occurred regardless of the position of the subset or superset (e.g., hatch, drama, howl), and in Experiment 1, were obtained for subsets that maintained (e.g., card) and changed their pronunciation (e.g., crown). Congruency effects were only found when the subsets were of higher frequency than the target. The implications for theories of word identification are discussed.

Dividing attention across multiple words occasionally results in misidentifications whereby letters apparently migrate between words. Previous studies have found that letter migrations preserve withinword letter position, which has been interpreted as support for position-specific letter coding. To investigate this issue, the authors used word pairs like STEP and SOAP, in which a letter in 1 word could migrate to an adjacent letter in another word to form an illusory word (STOP). Three experiments show that both same-position and adjacent-position letter migrations can occur, as well as migrations that cross 2 letter positions. These results argue against position-specific letter coding schemes used in many computational models of reading, and they provide support for coding schemes based on relative rather than absolute letter position.

We assessed the impact of visual similarity on written word identification by having participants learn new words (e.g. BANARA) that were neighbours of familiar words that previously had no neighbours (e.g. BANANA). Repeated exposure to these new words made it more difficult to semantically categorize the familiar words. There was some evidence of interference following an initial training phase, and clear evidence of interference the following day (without any additional training); interference was larger still following more training on the second day. These findings lend support to models of reading that include lexical competition as a key process. q

Many models of reading assume that visual word recognition is driven by a competitive activation process. In these models, the effect of a masked prime is to manipulate the competitive process by shifting the balance between the target stimulus and its competitors. Computational modelling makes it possible to explore these effects in detail. To this end, the present chapter develops a precise description of the factors underlying masked priming effects in a specific competitive network model -the interactive activation (IA) model . Because the resulting expression is formulated in terms of standard psycholinguistic variables, the analysis presented here helps to bridge the divide between purely computational accounts and verbal theories of visual word recognition and priming. This approach is assisted by a framework for partitioning the set of competitors of a target stimulus, and a graphical technique for depicting the course of the competitive process in competitive network models of visual word recognition. The development of simple regression models that are able to fully capture the effects of priming within a complex (interactive, nonlinear, and dynamic) network model is a valuable outcome that has broader implications for the computational modelling of cognition. The analysis of priming effects in the model also leads to a number of predictions that can be tested empirically.

Visual word identification requires readers to code the identity and order of the letters in a word and match this code against previously learned codes. Current models of this lexical matching process posit context-specific letter codes in which letter representations are tied to either specific serial positions or specific local contexts (e.g., letter clusters). The spatial coding model described here adopts a different approach to letter position coding and lexical matching based on context-independent letter representations. In this model, letter position is coded dynamically, with a scheme called spatial coding. Lexical matching is achieved via a method called superposition matching, in which input codes and learned codes are matched on the basis of the relative positions of their common letters. Simulations of the model illustrate its ability to explain a broad range of results from the masked form priming literature, as well as to capture benchmark findings from the unprimed lexical decision task.