Error detection in the performance of everyday tasks by patients with frontal lobe lesions: research and literature review

The research component of this thesis concerns awareness of when an error is made in the performance of an everyday task. It compares a group of patients with lesions involving the frontal lobes of the brain, to a group of patients whose lesions do not affect this area, and a group of healthy controls. A series of tasks was chosen that people are likely to carry out in everyday life, for greater ecological validity, and participants were videoed carrying these out under controlled conditions. A behavioural coding technique was used to keep a record of the errors made, and also whether there was any indication that the participant was aware of when they made an error. Participants were also asked periodically whether they thought they had made any errors, and what those errors might be. Patients with frontal lesions performed more poorly than healthy controls, although non-frontal patients differed significantly from neither group. When awareness of errors was considered, both patient groups differed from controls, but not from each other. A second experiment was conducted, where participants attempted to identify errors whilst watching their own videos. Under these conditions, frontal patients identified significantly less errors than either non-frontal patients or controls. Reasons for this, and the relevance to different theories are discussed. This paper is prepared for submission to Cognitive Neuropsychology. The review paper considers the literature on human error detection in general, and its relevance to clinical psychology. The main research paradigms used in this area of study are considered, and emphasis is given to the idea that the human cognitive system has some kind of in-built system for error detection. The literature on error detection in clinical populations is considered. Although this is a relatively new field of study, evidence is accumulating that certain clinical populations do experience difficulty in error detection, and in some cases, this plays a crucial role in understanding the disorder. Data from both clinical and non-clinical populations is considered, and it is concluded that both sources can be used to shed light on the other. This paper is prepared for submission to Clinical Psychology Review

Re-evaluating age-of-acquisition effects: Are they simply cumulative-frequency effects?

Abstract The time it takes to read or produce a word is in¯uenced by the word's age of acquisition (AoA) and its frequency (e.g. Quarterly Journal of Experimental Psychology 12 (1973) 85). Lewis (Cognition 71 (1999) B23) suggested that a parsimonious explanation would be that it is the total number of times a word has been encountered that predicts reaction times. Such a cumulative-frequency hypothesis, however, has always been rejected because the statistical effects of AoA and frequency are additive. Here, it is demonstrated mathematically that the cumulative-frequency hypothesis actually predicts such results when applied to curvilinear learning. Further, the data from four in¯uential studies (two of which claim support for independent effects of AoA and frequency) are re-analyzed to reveal that, in fact, they are consistent with a cumulative-frequency hypothesis. The conclusion drawn is that there is no evidence with which to refute the most parsimonious of explanations, i.e. cumulative frequency can account for both frequency and AoA effects.

The British Lexicon Project: Lexical decision data for 28,730 monosyllabic and disyllabic English words

We present a new database of lexical decision times for English words and nonwords, for which two groups of British participants each responded to 14,365 monosyllabic and disyllabic words and the same number of nonwords for a total duration of 16 h (divided over multiple sessions). This database, called the British Lexicon Project (BLP), fills an important gap between the Dutch Lexicon Project (DLP; Keuleers, Diependaele, & Brysbaert, Frontiers in Language Sciences. Psychology, 1, 174, 2010) and the English Lexicon Project (ELP; Balota et al., 2007), because it applies the repeated measures design of the DLP to the English language. The high correlation between the BLP and ELP data indicates that a high percentage of variance in lexical decision data sets is systematic variance, rather than noise, and that the results of megastudies are rather robust with respect to the selection and presentation of the stimuli. Because of its design, the BLP makes the same analyses possible as the DLP, offering researchers with a new interesting data set of word-processing times for mixed effects analyses and mathematical modeling. The BLP data are available at http://crr.ugent.be/blp and as Electronic Supplementary Materials