Size matters: saccades during scene perception

We investigated the effect of image size on saccade amplitudes. First, in a meta-analysis, relevant results from previous scene perception studies are summarised, suggesting the possibility of a linear relationship between mean saccade amplitude and image size. Forty-eight observers viewed 96 colour scene images scaled to four different sizes, while their eye movements were recorded. Mean and median saccade amplitudes were found to be directly proportional to image size, while the mode of the distribution lay in the range of very short saccades. However, saccade amplitudes expressed as percentages of image size were not constant over the different image sizes; on smaller stimulus images, the relative saccades were found to be larger, and vice versa. In sum, and as far as mean and median saccade amplitudes are concerned, the size of stimulus images is the dominant factor. Other factors, such as image properties, viewing task, or measurement equipment, are only of subordinate importance. Thus, the role of stimulus size has to be reconsidered, in theoretical as well as methodological terms.     

Motor coordination uses external spatial coordinates independent of developmental vision

The constraints that guide bimanual movement coordination are informative about the processing principles underlying movement planning in humans. For example, symmetry relative to the body midline benefits finger and hand movements independent of hand posture. This symmetry constraint has been interpreted to indicate that movement coordination is guided by a perceptual code. Although it has been assumed implicitly that the perceptual system at the heart of this constraint is vision, this relationship has not been tested. Here, congenitally blind and sighted participants made symmetrical and non-symmetrical (that is, parallel) bimanual tapping and finger oscillation movements. For both groups, symmetrical movements were executed more correctly than parallel movements, independent of anatomical constraints like finger homology and hand posture. For the blind, the reliance on external spatial factors in movement coordination stands in stark contrast to their use of an anatomical reference frame in perceptual processing. Thus, the externally coded symmetry constraint evident in bimanual coordination can develop in the absence of the visual system, suggesting that the visual system is not critical for the establishment of an external-spatial reference frame in movement coordination.     

An accumulator model for responses and response times in tests based on the proportional hazards model

Latent trait models for responses and response times in tests often lack a substantial interpretation in terms of a cognitive process model. This is a drawback because process models are helpful in clarifying the meaning of the latent traits. In the present paper, a new model for responses and response times in tests is presented. The model is based on the proportional hazards model for competing risks. Two processes are assumed, one reflecting the increase in knowledge and the second the tendency to discontinue. The processes can be characterized by two proportional hazards models whose baseline hazard functions correspond to the temporary increase in knowledge and discouragement. The model can be calibrated with marginal maximum likelihood estimation and an application of the ECM algorithm. Two tests of model fit are proposed. The amenability of the proposed approaches to model calibration and model evaluation is demonstrated in a simulation study. Finally, the model is used for the analysis of two empirical data sets.     

The Others Will Help: The Presence of Multiple Video Game Characters Reduces Helping After the Game Is Over

The bystander effect refers to the phenomenon that individuals are less likely to help if there are potential other helpers present. For instance, past research revealed that participants were less likely to help computer-controlled characters if there were other computer-controlled characters present. Research has also shown that the bystander effect occurs if the presence of others is merely imagined. The present research examined the idea that the presence of multiple characters within a video game reduces the player's helping behavior even after the video game is over. In fact, participants who played a video game with multiple characters present were less likely to devote time to assisting in a future study than participants who had played the same video game with only a single character present.     

Noncompetitive retrieval practice causes retrieval-induced forgetting in cued recall but not in recognition

Retrieving a subset of learned items can lead to the forgetting of related items. Such retrieval-induced forgetting (RIF) can be explained by the inhibition of irrelevant items in order to overcome retrieval competition when the target item is retrieved. According to the retrieval inhibition account, such retrieval competition is a necessary condition for RIF. However, research has indicated that noncompetitive retrieval practice can also cause RIF by strengthening cue–item associations. According to the strength-dependent competition account, the strengthened items interfere with the retrieval of weaker items, resulting in impaired recall of weaker items in the final memory test. The aim of this study was to replicate RIF caused by noncompetitive retrieval practice and to determine whether this forgetting is also observed in recognition tests. In the context of RIF, it has been assumed that recognition tests circumvent interference and, therefore, should not be sensitive to forgetting due to strength-dependent competition. However, this has not been empirically tested, and it has been suggested that participants may reinstate learned cues as retrieval aids during the final test. In the present experiments, competitive practice or noncompetitive practice was followed by either final cued-recall tests or recognition tests. In cued-recall tests, RIF was observed in both competitive and noncompetitive conditions. However, in recognition tests, RIF was observed only in the competitive condition and was absent in the noncompetitive condition. The result underscores the contribution of strength-dependent competition to RIF. However, recognition tests seem to be a reliable way of distinguishing between RIF due to retrieval inhibition or strength-dependent competition.     

Warm,but Maybe Not So Competent?—Contemporary Implicit Stereotypes of Women and Men in Germany

A fundamental model of stereotypes, the stereotype content model (SCM, Fiske et al. 2002), postulates that stereotypes of many social groups vary on two core dimensions: warmth and competence. In line with traditional gender stereotypes, the SCM predicts women to be perceived as warmer than men, and men to be perceived as more competent than women. Research on implicit measurement of stereotypes suggests that, next to people’s underlying beliefs, a major predictor is the tendency to favor one’s own group (Rudman et al. 2001). We examined gender stereotypes concerning warmth and competence, using implicit association tests (IATs, Greenwald et al. 1998) and drawing on diverse samples of women and men in eastern and western Germany (i.e., students and non-students; total N?=?384). On the warmth dimension, an overall women-warmth stereotype was found, confirming predictions of the SCM. On the competence dimension, associations of own gender and competence were observed for both men and women, suggesting the impact of self-favoring processes. Findings are discussed with respect to social role theory (Eagly 1987) and the changing roles of women.