Categorization of visual stimuli in the honeybee Apis mellifera

Categorization refers to the classification of perceptual input into defined functional groups. We present and discuss evidence suggesting that stimulus categorization can also be found in an invertebrate, the honeybee Apis mellifera, thus underlining the generality across species of this cognitive process. Honeybees show positive transfer of appropriate responding from a trained to a novel set of visual stimuli. Such a transfer was demonstrated for specific isolated features such as symmetry or orientation, but also for assemblies (layouts) of features. Although transfer from training to novel stimuli can be achieved by stimulus generalization of the training stimuli, most of these transfer tests involved clearly distinguishable stimuli for which generalization would be reduced. Though in most cases specific experimental controls such as stimulus balance and discriminability are still required, it seems appropriate to characterize the performance of honeybees as reflecting categorization. Further experiments should address the issue of which categorization theory accounts better for the visual performances of honeybees.This contribution is part of the special issue “Animal Logics” (Watanabe and Huber 2006).     

Short- and long-term consequences in decision-making under risk: immediate feedback about long-term prospects benefits people tending to impulsive processing

Many decisions in everyday life involve weighing up immediate and expected future outcomes that may be conflictive. Yet, it is still unclear which cognitive functions may affect decision-making in such situations. We examined 150 healthy subjects using a new decision-making task that measures people’s ability at handling short- and long-term consequences under objective risk. Two task versions were developed to investigate the effects of feedback about long-term consequences on decision-making. One version includes feedback about changes in long-term prospects while the other does not. Both groups revealed that advantageous decision-making correlated with reasoning and working-memory abilities, however, no correlations with executive functions were found. The effect of feedback on decision-making performance was moderated by impulsivity and need for cognition. Our findings contribute to recent dual-system approaches for risky decision-making by showing that individuals with predispositions towards impulsive rather than reflective information processing could profit from feedback about long-term prospects.     

Category and perceptual interference in second-language phoneme learning: an examination of English /w/-/v/ learning by Sinhala, German, and Dutch speakers

The present study investigated the perception and production of English /w/ and /v/ by native speakers of Sinhala, German, and Dutch, with the aim of examining how their native language phonetic processing affected the acquisition of these phonemes. Subjects performed a battery of tests that assessed their identification accuracy for natural recordings, their degree of spoken accent, their relative use of place and manner cues, the assimilation of these phonemes into native-language categories, and their perceptual maps (i.e., multidimensional scaling solutions) for these phonemes. Most Sinhala speakers had near-chance identification accuracy, Germans ranged from chance to 100% correct, and Dutch speakers had uniformly high accuracy. The results suggest that these learning differences were caused more by perceptual interference than by category assimilation; Sinhala and German speakers both have a single native-language phoneme that is similar to English /w/ and /v/, but the auditory sensitivities of Sinhala speakers make it harder for them to discern the acoustic cues that are critical to /w/-/v/ categorization.     

Eye movements and behavioral responses to threatening and nonthreatening stimuli during visual search in phobic and nonphobic subjects

Spider-phobic and nonphobic subjects searched for a feared/fear-relevant (spider) or neutral target (mushroom) presented in visual matrices of neutral objects (flowers). In half of the displays, the mushroom target was paired with a spider distractor, or a spider target was paired with a mushroom distractor. Although all subjects responded faster to the neutral target than to the feared/fear-relevant target, phobics were slower to respond than nonphobics when a mushroom target was presented with a spider distractor. Their eyes appeared to be drawn to the feared distractor before fixating neutral targets. A further experiment indicated no group differences when subjects merely judged the homogeneity of matrices. Thus, threat seems to capture the attention of phobics only when it is part of a background that subjects are explicitly instructed to ignore.     

The role of structural prediction in rapid syntactic analysis

A number of recent electrophysiological studies of sentence processing have shown that a subclass of syntactic violations elicits very rapid ERP responses, occurring within around 200 ms of the onset of the violation. Such findings raise the question of how it is possible to diagnose violations so quickly. This paper suggests that very rapid diagnosis of errors is possible specifically in situations where the diagnosis problem is tightly constrained by specific expectations generated before the critical word is presented. In an event-related potentials (ERP) study of visual sentence reading participants encountered violations of a word order constraint (...Max's of...) that has elicited early ERP responses in previous studies. Across conditions the illicit sequence was held constant, while sentence context was used to manipulate the expectation for a noun following the possessor Max's, by manipulating the possibility of ellipsis of the head noun. Results showed that the anterior negativity elicited by the word category violation was attenuated when the availability of ellipsis reduced the expectation for a noun in the position of the offending preposition of, with divergence between conditions starting around 200 ms after the onset of the violation. This suggests a role for structural expectations in accounting for very fast syntactic diagnosis processes.     

‘Acting in the Children’s Best Interest?’: Examining Victims’ Responses to Intimate Partner Violence

Victims’ responses to violent experiences within intimate relationships are highly diverse and can range from remaining silent, at least temporarily, to disclosing the abuse to informal and formal sources of support. Decisions to remain silent or to reach out for support are influenced by a complex range of factors, including situational circumstances, such as the presence of children. Using data from in-depth interviews with victims of IPV (N = 29) in Southeast Queensland, Australia, I examined victims’ responses to IPV when children are present in the abusive household. Victims, who accessed general formal support sources, including the criminal justice systems and Child Protection Services (CPS), frequently faced stereotypical and victim-blaming attitudes along with a lack of understanding of the dynamics of IPV and the circumstances surrounding victims’ help-seeking decisions. The presence of children in abuse relationships complicated victims’ help-seeking decisions because fear of harm and loss of custody often delayed or hindered the disclosure of IPV to formal support sources. Once disclosing the abuse victims often found themselves trapped between CPS expectations to protect their children by leaving the abusive partner and a reluctance on behalf of judges and magistrates to offer the necessary protection by including children on granted Domestic Violence Orders (DVO). These findings highlight the ongoing need for specialized training of CPS personnel, judges and magistrates along with an ongoing collaboration with the women’s sector to ensure the safety of victims and their children throughout the help-seeking process and to improve victims’ confidence in disclosing IPV.     

Illusory correlations revisited: the role of pseudocontingencies and working-memory capacity

Three experiments investigate illusory correlations in a feedback learning paradigm. Diverging from a standard paradigm, in which stimuli consist of joint observations of group-behaviour pairs, participants were asked to guess the group reference of positive and negative stimulus behaviours. They only knew that one group was larger than the other, and the stimulus series soon revealed that positive (negative) behaviours appeared more frequently in the stimulus series than negative (positive) behaviours. Regardless of whether feedback of the actual group reference was provided or not, the predominant valence was more strongly associated with the large than the small group. This illusory-correlation effect was evident in memory-based measures at the end of the stimulus series as well as in the online predictions during stimulus presentation. The strength of illusory correlations increased with decreasing working-memory capacity, operationalized either by an interpersonal differences measure or a cognitive-load manipulation. The occurrence of illusory correlations in the absence of joint observations about group-valence pairs (in the no-feedback condition and in the early phase of the online prediction task) can be explained as a reflection of pseudocontingency inferences.     

Deindividuation,anonymity, and violence: findings from Northern Ireland

The author examined the relation between anonymity and aggression in violent interpersonal assaults that occurred in Northern Ireland. Of the 500 violent attacks that the author studied, 206 were carried out by offenders who wore disguises to mask their identities. The findings revealed that significant positive relationships existed between the use of disguises and several measures of aggression. Disguised offenders inflicted more serious physical injuries, attacked more people at the scene, engaged in more acts of vandalism, and were more likely to threaten victims after the attacks. The author discussed these results within the framework of deindividuation theory.