Combining speed and accuracy in cognitive psychology: is the Inverse Efficiency Score (IES) a better dependent variable than the mean Reaction Time (RT) and the Percentage of Errors (PE)?

Experiments in cognitive psychology usually return two dependent variables: the percentage of errors and the reaction time of the correct responses. Townsend and Ashby (1978, 1983) proposed the inverse efficiency score (IES) as a way to combine both measures and, hence, to provide a better summary of the findings. In this article we examine the usefulness of IES by applying it to existing datasets. Although IES does give a better summary of the findings in some cases, mostly the variance of the measure is increased to such an extent that it becomes less interesting. Against our initial hopes, we have to conclude that it is not a good idea to limit the statistical analyses to IES without further checking the data

The construction and preliminary validation of an instrument to assess the food fantasies of individuals with eating disorders

The study's goal was to develop and initially validate the Food Fantasies Questionnaire, a self-report therapeutic and research instrument which assesses the occurrence and content of highly irrational food cognitions (fantasies) common to eating disorders in relation to seven theoretically derived factors characterisic of the disorders: fear, anxiety, revulsion, pleasure, gender, animation and control. Whether food fantasies can be grouped by common factors, and if the fantasies as described reflected their designated factor was also investigated. One hundred and ten (110) fantasy-items were evaluated and designated represesntative of a factor by a DELPHI Panel. The final tool contained 42 items, six per factor. A six-point Likert scale indicated the frequency of occurrence. The instrument was administered by specialized therapists to 52 young women in outpatient individual and/or group therapy for anorexia, bulimia, bulimia nervosa or compulsive overeating. The reliability coeffeciant was +.9411. The seven factor solution of the R-mode analysis extracted 39 fantasies with factor loadings equal to or above +.44. The generated factors were labeled: Control Fears and Anxieties; Animation and Ambivalence; Gender and Social Acceptance; Autonomous versus Conscious Control of Food Thoughts; Pleasure; Animation, Childlike Reasoning; and Revulsion. It is concluded that fantasies can be grouped by factors, four which were similar to those designated by the DELPHI Panel. Fear and Anxiety appear to address the same trait and are related to Control. The research design utilizing a priori factors, the DELPHI Technique and factor analysis shows promise as a method of establishing initial validity

Beliefs about the Minds of Others Influence How We Process Sensory Information

Attending where others gaze is one of the most fundamental mechanisms of social cognition. The present study is the first to examine the impact of the attribution of mind to others on gaze-guided attentional orienting and its ERP correlates. Using a paradigm in which attention was guided to a location by the gaze of a centrally presented face, we manipulated participants' beliefs about the gazer: gaze behavior was believed to result either from operations of a mind or from a machine. In Experiment 1, beliefs were manipulated by cue identity (human or robot), while in Experiment 2, cue identity (robot) remained identical across conditions and beliefs were manipulated solely via instruction, which was irrelevant to the task. ERP results and behavior showed that participants' attention was guided by gaze only when gaze was believed to be controlled by a human. Specifically, the P1 was more enhanced for validly, relative to invalidly, cued targets only when participants believed the gaze behavior was the result of a mind, rather than of a machine. This shows that sensory gain control can be influenced by higher-order (task-irrelevant) beliefs about the observed scene. We propose a new interdisciplinary model of social attention, which integrates ideas from cognitive and social neuroscience, as well as philosophy in order to provide a framework for understanding a crucial aspect of how humans' beliefs about the observed scene influence sensory processing

Facial identity and facial expression are initially integrated at visual perceptual stages of face processing

It is frequently assumed that facial identity and facial expression are analysed in functionally and anatomically distinct streams within the core visual face processing system. To investigate whether expression and identity interact during the visual processing of faces, we employed a sequential matching procedure where participants compared either the identity or the expression of two successively presented faces, and ignored the other irrelevant dimension. Repetitions versus changes of facial identity and expression were varied independently across trials, and event-related potentials (ERPs) were recorded during task performance. Irrelevant facial identity and irrelevant expression both interfered with performance in the expression and identity matching tasks. These symmetrical interference effects show that neither identity nor expression can be selectively ignored during face matching, and suggest that they are not processed independently. N250r components to identity repetitions that reflect identity matching mechanisms in face-selective visual cortex were delayed and attenuated when there was an expression change, demonstrating that facial expression interferes with visual identity matching. These findings provide new evidence for interactions between facial identity and expression within the core visual processing system, and question the hypothesis that these two attributes are processed independently

The Effect of Real-World Personal Familiarity on the Speed of Face Information Processing

Background. Previous studies have explored the effects of familiarity on various kinds of visual face judgments, yet the role of familiarity in face processing is not fully understood. Across different face judgments and stimulus sets, the data is equivocal as to whether or not familiarity impacts recognition processes. Methodology/Principal Findings. Here, we examine the effect of real-world personal familiarity in three simple delayed-match-to-sample tasks in which subjects were required to match faces on the basis of orientation (upright v. inverted), gender and identity. We find that subjects had a significant speed advantage with familiar faces in all three tasks, with large effects for the gender and identity matching tasks. Conclusion/Significance. Our data indicates that real-world experience with a face exerts a powerful influence on face processing in tasks where identity information is irrelevant, even in tasks that could in principle be solved via low-level cues. These results underscore the importance of experience in shaping visual recognition processes

Agenesia e lipoma de corpo caloso: relato de caso

The agenesis and lipoma of the corpus callosum is a very rare association. We report the case of a 18-years old woman with rare epileptic seizures since the age of 6 years, normal neurological examination, as well as normal electroencephalogram. The brain computed tomography scanning and the magnetic resonance showed the lipoma and the agenesis of the corpus callosum.A agenesia e lipoma do corpo caloso é uma associação muito rara. Relatamos o caso de uma paciente de 18 anos com raras crises epilépticas desde os 6 anos de idade, exame neurológico normal, assim como eletrencefalograma normal. A tomografia computadorizada de crânio e a ressonância magnética mostraram o lipoma e a agenesia de corpo caloso.Escola Paulista de MedicinaUNIFESP, EPMSciEL