Using statistical smoothing to estimate the psycholinguistic acceptability of novel phrases

Native speakers of languages perceive differences in the acceptability of phrases even when those phrases are both grammatical and novel (previously unseen). We suggest that smoothing, a statistical technique used by natural language processing engineers, provides several candidate mechanisms for investigating this phenomenon. We describe the creation of a large data set of predictions from several smoothing algorithms about the acceptability of unseen grammatical phrases and a novel experimental method for the pairwise comparison of these models. We use this method to compare three smoothing methods and consider the results in light of the differences among the models. We argue that the data support the idea that similarity in this domain is best thought of as a form of asymmetric representational distortion and that the informational basis over which such estimates are made is broad, rather than narrow, as has been previously suggested.     

Costs in searching for two targets: dividing search across target types could improve airport security screening

The cost of searching for two visual targets simultaneously was compared against two separate single‐target searches using exposure time and accuracy measures within a staircase procedure. Dual‐target search for all stimuli (colour, shape and orientation) exhibited a loss of accuracy for one target. For orientation and shape, this dual‐target cost in accuracy was extreme, with chance‐level performance on one target. For colour, dual‐target search exhibited an additional cost in search time, with search requiring a longer exposure than the summed time required for two single‐target searches. An additional search‐time cost was also found for orientation targets when irrelevant colour variation was added to the display. In conclusion, dual‐target search for dissimilar targets is accompanied by an accuracy cost. Furthermore, colour variation, whether task‐relevant or not, leads to an additional cost in processing speed. The results suggest that a divided‐effort strategy would improve performance in search tasks such as X‐ray baggage screening. Copyright © 2006 John Wiley & Sons, Ltd.     

Financial prospect relativity: context effects in financial decision‐making under risk

We report three studies in which methodologies from psychophysics are adapted to investigate context effects on individual financial decision‐making under risk. The aim was to determine how the range and the rank of the options offered as saving amounts and levels of investment risk influence people's decisions about these variables. In the range manipulation, participants were presented with either a full range of choice options or a limited subset, while in the rank manipulation they were presented with a skewed set of feasible options. The results showed that choices are affected by the position of each option in the range and the rank of presented options, which suggests that judgments and choices are relative. Copyright © 2006 John Wiley & Sons, Ltd.     

Looking before you leap: A theory of motivated control of action

The acquisition of volitional control depends, in part, on developing the ability to countermand a planned action. Many tasks have been used to tap the efficiency of this process, but few studies have investigated how it may be modulated by participants’ motivation. Multiple mechanisms may be involved in the deliberate exercise of caution when incentives are provided. For example, control may involve modulation of the efficiency of the countermanding process, and/or inhibitory modulation of the impulse to go. One of the most commonly used paradigms to assess control of action is the Stop Signal Task, in which a primary Go stimulus is occasionally followed by a countermanding Stop signal, allowing a Stop Signal Reaction Time (SSRT) to be inferred as the outcome of a “horse race” between the go and countermanding processes. Here, we present a computational model in which high task motivation modulates proactive pre-stimulus inhibition of the go response. This allows responses to be calibrated so as to fall within a time-window that maximizes the probability of success, regardless of trial type, but does not decrease the observed SSRT. We report empirical support for the model from a sample of typically developing children, and discuss the broader implications for operationalizing measures of volitional control.     

Visual search in children and adults: top-down and bottom-up mechanisms

Three experiments investigated visual search for targets that differed from distractors in colour, size, or orientation. In one condition the target was defined by a conjunction of these features, while in the other condition the target was the odd one out. In all experiments, 6-7- and 9-10-year-old children were compared with young adults. Experiment 1 showed that children's search differed from adults' search in two ways. In conjunction searches children searched more slowly and took longer to reject trials when no target was present. In the odd-one-out experiments, 6-7-year-old children were slower to respond to size targets than to orientation targets, and slower for orientation targets than for colour targets. Both the other groups showed no difference in their rate of responding to colour and orientation. Experiments 2 and 3 highlighted that these results were not a function of either differential density across set sizes (Experiment 2) or discriminability of orientation and colour (Experiment 3). Across all three experiments, the results of both conjunction and odd-one-out searches highlighted a development in visual search from middle to late childhood.     

Helping to improve the group stereotype: on the strategic dimension of prosocial behavior

Three studies consider a basis for intergroup helping. Specifically, they show that group members may help others to disconfirm a stereotype of their own group as mean. Study 1 shows that Scots believe they are seen as mean by the English, resent this stereotype, are motivated to refute it, and believe out-group helping is a particularly effective way of doing so. Study 2 shows that increasing the salience of the English stereotype of the Scottish as mean leads Scots to accentuate the extent to which Scots are depicted as generous. Study 3 shows that increasing the salience of the stereotype of the Scots as mean results in an increase in the help volunteered to out-group members. These results highlight how strategic concerns may result in out-group helping. In turn, they underscore the point that helping others may be a means to advance a group's interest.