Context-dependent olfactory learning monitored by activities of salivary neurons in cockroaches

Context-dependent discrimination learning, a sophisticated form of nonelemental associative learning, has been found in many animals, including insects. The major purpose of this research is to establish a method for monitoring this form of nonelemental learning in rigidly restrained insects for investigation of underlying neural mechanisms. We report context-dependent olfactory learning (occasion-setting problem solving) of salivation, which can be monitored as activity changes of salivary neurons in immobilized cockroaches, Periplaneta americana. A group of cockroaches was trained to associate peppermint odor (conditioned stimulus, CS) with sucrose solution reward (unconditioned stimulus, US) while vanilla odor was presented alone without pairing with the US under a flickering light condition (1.0 Hz) and also trained to associate vanilla odor with sucrose reward while peppermint odor was presented alone under a steady light condition. After training, the responses of salivary neurons to the rewarded peppermint odor were significantly greater than those to the unrewarded vanilla odor under steady illumination and those to the rewarded vanilla odor was significantly greater than those to the unrewarded peppermint odor in the presence of flickering light. Similar context-dependent responses were observed in another group of cockroaches trained with the opposite stimulus arrangement. This study demonstrates context-dependent olfactory learning of salivation for the first time in any vertebrate and invertebrate species, which can be monitored by activity changes of salivary neurons in restrained cockroaches.     

The use of olfactory cues in solving a visual discrimination task

Albino rats, trained in a miniaturized WGTA, were found to learn an olfactory discrimination despite the fact that visual cues were relevant and obvious. The results provide a further warning against the use of macrosmatic animals in visual discrimination tasks in which olfactory cues may be relevant.     

The use of social and salience cues in early word learning

This article explores young infants' ability to learn new words in situations providing tightly controlled social and salience cues to their reference. Four experiments investigated whether, given two potential referents, 15-month-olds would attach novel labels to (a) an image toward which a digital recording of a face turned and gazed, (b) a moving image versus a stationary image, (c) a moving image toward which the face gazed, and (d) a gazed-on image versus a moving image. Infants successfully used the recorded gaze cue to form new word-referent associations and also showed learning in the salience condition. However, their behavior in the salience condition and in the experiments that followed suggests that, rather than basing their judgments of the words' reference on the mere presence or absence of the referent's motion, infants were strongly biased to attend to the consistency with which potential referents moved when a word was heard.     

Adults' social cues facilitate young children's use of signs and symbols

Three experiments investigated the effect of an adult's social cues on 2- and 3-year-old children's ability to use a sign or symbol to locate a hidden object. Results showed that an adult's positive, engaging facial expression facilitated children's ability to identify the correct referent, particularly for 3-year-olds. A neutral facial expression and the presence of the adult's hand also facilitated performance, but to a lesser degree than did an engaging facial expression. The effect of the adult's social cues was greater for relatively unfamiliar signs and symbols (replica or arrow) than it was for a more familiar sign (pointing finger). These findings indicate that non-directional social cues such as facial expression help to convey communicative intent and facilitate children's comprehension of signs and symbols.     

Knowledge partitioning: Context-dependent use of expertise

Although exceptional performance is a defining attribute of expertise, experts sometimes exhibit striking errors and performance limitations. This article reports two experiments in which experts predicted the spread of bush fires, a domain characterized by complex but well-understood physical dynamics. Although accuracy was typically high, large errors were observed when two primary predictor variables were in opposition. In a second study, the experts' behavior--in contrast to that of novices--was additionally shown to depend on problem context. In one context, experts again committed errors, whereas in another, equally domain-relevant context, the correct predictions were made. Critically, when comparing performance across contexts, completely opposing predictions were made under identical physical conditions. We therefore suggest that expertise may comprise separate, and sometimes even mutually exclusive, components of knowledge.     

Processing of invisible social cues

Successful interactions between people are dependent on rapid recognition of social cues. We investigated whether head direction – a powerful social signal – is processed in the absence of conscious awareness. We used continuous flash interocular suppression to render stimuli invisible and compared the reaction time for face detection when faces were turned towards the viewer and turned slightly away. We found that faces turned towards the viewer break through suppression faster than faces that are turned away, regardless of eye direction. Our results suggest that detection of a face with attention directed at the viewer occurs even in the absence of awareness of that face. While previous work has demonstrated that stimuli that signal threat are processed without awareness, our data suggest that the social relevance of a face, defined more broadly, is evaluated in the absence of awareness.     

Spatial orienting of tactile attention induced by social cues

Several studies have established that humans orient their visual attention reflexively in response to social cues such as the direction of someone else’s gaze. However, the consequences of this kind of orienting have been addressed only for the visual system. We investigated whether visual social attention cues can induce shifts in tactile attention by combining a central noninformative eye-gaze cue with tactile targets presented to participants’ fingertips. Data from speeded detection, speeded discrimination, and signal detection tasks converged on the same conclusion: Eye-gaze-based orienting facilitates the processing of tactile targets at the location of the gazed-at body location. In addition, we examined the effects of other directional cues, such as conventional arrows, and found that they can be equally effective. This is the first demonstration that social attention cues have consequences that reach beyond their own sensory modality.     

Rejection sensitivity and disruption of attention by social threat cues

Two studies tested the hypothesis that Rejection Sensitivity (RS) increases vulnerability to disruption of attention by social threat cues, as would be consistent with prior evidence that it motivates individuals to prioritize detecting and managing potential rejection at a cost to other personal and interpersonal goals. In Study 1, RS predicted disruption of ongoing goal-directed attention by social threat but not negative words in an Emotional Stroop task. In Study 2, RS predicted attentional avoidance of threatening but not pleasant faces in a Visual Probe task. Threat-avoidant attention was also associated with features of borderline personality disorder. This research extends understanding of processes by which RS contributes to a self-perpetuating cycle of interpersonal problems and distress.     

Discrimination by olfactory cues in albino rats reflecting familiarity and relatedness among conspecifics

The present investigation sought to determine whether albino rat pups could discriminate among familiar siblings, nonfamiliar siblings, familiar nonsiblings (foster littermates), and nonfamiliar nonsiblings (unrelated agemates) using only olfactory cues. Pairing all possible combinations of familiarity and kinship variables (six), the odors were presented in paired combinations to each of twelve experimental subjects. Results from dependent t tests indicated that the albino rat pups could discriminate between the following pairs of odors using only the olfactory sensory modality: (a) familial siblings and nonfamiliar siblings, (t = 3.41, p = .006); (b) familiar siblings and nonfamiliar nonsiblings, (t = 9.62, p = .001); (c) nonfamiliar siblings and nonfamiliar nonsiblings, (t = 3.15, p = .009); and (d) familiar nonsiblings and nonfamiliar nonsiblings (t = 2.58, p = .026).     

Context-dependent variation in social stereotyping 1: The effects of intergroup relations as mediated by social change and frame of reference

During the 1990-1991 Persian Gulf conflict an experiment was conducted with Australian university students (N = 200) to investigate whether the social stereotyping of Americans varied with social contextual manipulations related to the hostilities. The study, conducted in two phases at the start and end of the conflict, examined how the assignment of standard stereotypical traits to Americans was affected (a) by the large-scale social change constituted by the war and (b) by variation in the frame of reference provided by relevant comparison groups. The elicited stereotypes were sensitive to both of these contextual variables, demonstrating significant variation and fluidity. Overall, stereotypes of Americans were relatively negative. They were significantly more negative (a) at the end of the war than at the beginning in the restricted frame (when Australia and Britain were comparison groups) and (b) in the first phase of the conflict when the frame was extended to include Iraq as a comparison group. The findings were in line with expectations derived from self-categorization theory (Turner, 1985) that the social categorization of self and other into ingroup and outgroup is inherently variable, comparative and context-dependent. They question the long-held view of stereotypes as fixed, rigid and resistant to change.     

Neuroticism predicts reactions to cues of social inclusion

In the current paper, we hypothesized that people who are high in neuroticism (N) share a motivational predisposition to react vigilantly to threatening cues, most of which tend to be social in humans. In three studies, support for this prediction was found: based on cross‐sectional and diary data, it was found that the self‐esteem (SE) of individuals high in N decreases more in response to perceptions of relationship conflict and low relationship quality than that of emotionally stable ones. In a study of people's reactions to imagined threats, neurotic individuals showed a heightened sensitivity to both nonsocial and social cues, though reactions to social cues were somewhat more pronounced. Results are consistent with principles from evolutionary and process‐oriented personality psychology. Copyright © 2008 John Wiley & Sons, Ltd.     

The use of prosodic cues in language discrimination tasks by rats

Recent research with cotton-top tamarin monkeys has revealed language discrimination abilities similar to those found in human infants, demonstrating that these perceptual abilities are not unique to humans but are also present in non-human primates. Specifically, tamarins could discriminate forward but not backward sentences of Dutch from Japanese, using both natural and synthesized utterances. The present study was designed as a conceptual replication of the work on tamarins. Results show that rats trained in a discrimination learning task readily discriminate forward, but not backward sentences of Dutch from Japanese; the results are particularly robust for synthetic utterances, a pattern that shows greater parallels with newborns than with tamarins. Our results extend the claims made in the research with tamarins that the capacity to discriminate languages from different rhythmic classes depends on general perceptual abilities that evolved at least as far back as the rodents. Electronic Publication     

The use of anticipatory visual cues by highly skilled tennis players

The authors examined 13 skilled and 12 novice tennis performers' ability to use visual information of an opponent's movement pattern to anticipate and respond. In Experiment 1, skilled and novice players anticipated the type of stroke and the direction in which the ball was hit in a highly coupled perception-action environment. Both groups of players correctly anticipated at greater than chance levels. Skilled players were significantly more accurate than novices with live and video displays but not with point-light displays. In Experiment 2, the reaction latencies of 10 expert performers were significantly faster when they returned balls hit by a live opponent than when they returned balls projected from a cloaked ball machine. The findings indicate that experts are able to use movement-pattern information to determine shot selection and to use that information to significantly reduce their response delay times. The findings are discussed in terms of perception-action coupling in time-stress activities.     

A naturalistic study of autobiographical memories evoked by olfactory and visual cues: testing the Proustian hypothesis

The emotional and evocative qualities of autobiographical memories evoked by odors and visual cues were compared using a new repeated-measures paradigm in which the sensory cue was presented after the memory had been retrieved by its verbal label. Memory cues were chosen to be able to elicit salient memories. Results revealed that memories recalled in the context of odors were significantly more emotional than those recalled in the context of the same cue presented visually and by the verbal label for the cue. Odor-evoked memories also tended to make participants feel more "brought back" to the original event. This work is the first unequivocal demonstration that naturalistic memories evoked by odors are more emotional than memories evoked by other cues.     

Retrieval variability: The inefficient use of retrieval cues by young children

The hypothesis of this study is that the inefficient use of retrieval cues by young children is due to retrieval variability: the variable encoding of semantic information in cue stimuli at input and retrieval and the inability to reinterpret cue information to ensure cue-trace compatibility. The critical manipulations involved the use of semantic orienting questions at both input and retrieval. Second and fourth graders and college adults were given moderately associated word pairs (Knife-Axe). Encoding was constrained or free between groups at both input and retrieval. The retrieval questions biased the Same interpretation of the cue as at input (weapon), a uniquely Different interpretation (utensil), or an inappropriate Negative interpretation. Both cued recall and recognition of the target items was tested. The results showed systematic developmental increases both in the distinctiveness of the semantic encoding of stimulus information, and in the ability to reinterpret cue information to ensure cue-trace compatibility. The second graders encoded more variably than the older subjects, and were less able to shift from an incompatible encoding of cue information.     

The neural correlates of social attention: automatic orienting to social and nonsocial cues

Previous evidence suggests that directional social cues (e.g., eye gaze) cause automatic shifts in attention toward gaze direction. It has been proposed that automatic attentional orienting driven by social cues (social orienting) involves a different neural network from automatic orienting driven by nonsocial cues. However, previous neuroimaging studies on social orienting have only compared gaze cues to symbolic cues, which typically engage top-down mechanisms. Therefore, we directly compared the neural activity involved in social orienting to that involved in purely automatic nonsocial orienting. Twenty participants performed a spatial cueing task consisting of social (gaze) cues and automatic nonsocial (peripheral squares) cues presented at short and long stimulus (cue-to-target) onset asynchronies (SOA), while undergoing fMRI. Behaviorally, a facilitation effect was found for both cue types at the short SOA, while an inhibitory effect (inhibition of return: IOR) was found only for nonsocial cues at the long SOA. Imaging results demonstrated that social and nonsocial cues recruited a largely overlapping fronto-parietal network. In addition, social cueing evoked greater activity in occipito-temporal regions at both SOAs, while nonsocial cueing recruited greater subcortical activity, but only for the long SOA (when IOR was found). A control experiment, including central arrow cues, confirmed that the occipito-temporal activity was at least in part due to the social nature of the cue and not simply to the location of presentation (central vs. peripheral). These results suggest an evolutionary trajectory for automatic orienting, from predominantly subcortical mechanisms for nonsocial orienting to predominantly cortical mechanisms for social orienting.