Infants' perception of directional alignment of texture elements on a spherical surface

By appropriately compressing texture elements on a circular surface, one can evoke the impression of being confronted with the depiction of a spherical object in the picture plane. According to Todd and Akerstrom (1987), the 3D perception of such an object can be eliminated if the optical elements are not sufficiently elongated or if they are not aligned with one another. In the current investigation, 4‐month‐old infants were tested for their ability to react to a disruption of the directional alignment variable. They were habituated to either a spherical surface or a surface the spatial layout of which was destroyed by reorienting the texture elements, and were afterwards tested with a further ellipsoid object and with a further flat surface. Data analysis revealed that the female infants, but not the male participants, preferred the novel posthabituation display, that is, the test stimulus which included a change in the orientational alignment of texture elements. These findings are discussed within the context of development of sensitivity to pictorial depth cues. It is possible that infants as young as 4 months of age respond to manipulations of the directional alignment factor per se, while older infants are capable of using this factor as a cue for 3D object shape. Copyright © 2003 John Wiley & Sons, Ltd.     

Teaching Different Tasks Using Different Stimuli in a Heterogeneous Small Group

The effectiveness of a simultaneous prompting procedure was evaluated in a heterogeneous small group using different tasks and different stimuli for each student. Participants included four middle school students whose functioning levels ranged from typically developing to moderate and severe disabilities. A multiple probe design across behaviors and replicated across students was used. Observational learning maintenance, and generalization also were assessed. Results indicate that the procedure was successful in teaching all four students their targeted stimuli as well as some of the non-targeted stimuli (i.e., observational learning). Students maintained and generalized their information with a high degree of accuracy. Limitations of the study and future research implications are discussed.     

Use of experimenter-given cues in dogs

Since the observations of O. Pfungst the use of human-provided cues by animals has been well-known in the behavioural sciences (“Clever Hans effect”). It has recently been shown that rhesus monkeys (Macaca mulatta) are unable to use the direction of gazing by the experimenter as a cue for finding food, although after some training they learned to respond to pointing by hand. Direction of gaze is used by chimpanzees, however. Dogs (Canis familiaris) are believed to be sensitive to human gestural communication but their ability has never been formally tested. In three experiments we examined whether dogs can respond to cues given by humans. We found that dogs are able to utilize pointing, bowing, nodding, head-turning and glancing gestures of humans as cues for finding hidden food. Dogs were also able to generalize from one person (owner) to another familiar person (experimenter) in using the same gestures as cues. Baseline trials were run to test the possibility that odour cues alone could be responsible for the dogs’ performance. During training individual performance showed limited variability, probably because some dogs already “knew” some of the cues from their earlier experiences with humans. We suggest that the phenomenon of dogs responding to cues given by humans is better analysed as a case of interspecific communication than in terms of discrimination learning. Received: 30 May 1998 / Accepted after revision: 6 September 1998     

Peak shift following simultaneous discriminations

Pigeons were exposed to stimuli presented on two keys. For some birds, the stimuli varied in a dimension of visual flicker-rate, and for others they varied in visual intensity. During differential training, concurrent schedules operated, with one stimulus correlated with one schedule and another stimulus correlated with a second schedule that arranged a lower, or zero, rate of reinforcement. The stimuli were alternated randomly on the two keys. Generalization tests were given in which the original two, and seven other stimuli lying in the same dimension, were presented in pairs on the two keys in various combinations. In the generalization test given after differential training, each bird showed peak shift. The data did not support explanation for peak shift that gave critical emphasis to whether stimuli were presented simultaneously or successively during differential training.     

Effects of self-generated versus experimenter-provided cues on the representation of future events

Most experimental studies of prospection focused on episodic forms of future events prompted by means of verbal cues. However, there is evidence suggesting that future events differ considerably according to whether they are produced in response to external, experimenter-provided verbal cues or they are self-generated. In the present study, we compared the quality, the phenomenal characteristics, the temporal distribution, and the content of imagined events prompted by experimenter-provided cues (i.e., cue-words and short verbal sentences) or elicited by means of verbal cues that were self-generated in an autobiographical fluency task. The results showed that future events prompted by means of self-generated cues contained fewer event-specific details than future events prompted by experimenter-provided cues. However, future events elicited by means of self-generated and by experimenter-provided cues did not differ with respect to their phenomenal characteristics. The temporal distribution and the thematic content of future representations were also affected by the type of cue used to elicit prospection. These results offer a holistic view of the properties of future thinking and suggest that the content and the characteristics of envisioned future events may be affected by the method used to elicit prospection.     

Learning and foraging efficiency in German cockroaches, Blattella germanica (L.) (Insecta: Dictyoptera)

We analysed, under laboratory test conditions, how German cockroach larvae oriented their outgoing foraging trip from their shelter. Our results stressed the importance of external factors, like availability and spatial distribution of food sources, in the choice of a foraging strategy within their home range. When food sources were randomly distributed, larvae adopted a random food search strategy. When food distribution was spatially predictable and reliable, cockroaches were able to relate the presence of food with a landmark during a 3-day training period and to develop an oriented search strategy. Cockroaches were able to associate learned spatial information about their home range to the presence of food resources and then to improve their foraging efficiency. However, conflict experiments revealed that detection of food odour overrode learned landmark cues. Received: 16 October 1999 / Accepted after revision: 18 July 2000     

A meta-analysis of aggression in the presence of violent cues: Effects of gender differences and aversive provocation

Meta-analytically examines experimental studies that include violent cues in the setting and assesses the effects of aversive provocation on gender differences in aggression. The results show that when violent cues are present, men are more aggressive than women under neutral unprovoked conditions. However, when they are exposed to both violent cues and aversive provocation, men and women are equally aggressive. Differences in individual reactivity to violent cues as well as the type of aggressive response and the sex of the target also affected the magnitude of gender differences in the presence of violent cues. Aggr. Behav. 23:447–456, 1997. © 1997 Wiley-Liss, Inc.     

Mixing virtue and vice: combining the immediacy effect and the diversification heuristic

Many of the most significant choices that people make are between vices, which exchange small immediate rewards for large delayed costs, and virtues, which exchange small immediate costs for large delayed rewards. We investigate the consequences of making a series of such choices either simultaneously or sequentially. We made two predictions. First, because many alternatives chosen under simultaneous choice will only be experienced following a delay, and because hyperbolic time discounting predicts that people will prefer delayed virtues but immediate vices, we predicted that people would choose more virtues in simultaneous than sequential choice. Second, due to the tendency to diversify portfolios of choices, we predicted a greater mix of virtues and vices in simultaneous than sequential choice. These predictions were confirmed in two experiments involving real choices; one between ‘highbrow’ and ‘lowbrow’ movies, and the other between ‘instant‐win’ and ‘prize‐draw’ lottery tickets. We conclude by posing the question of whether simultaneous or sequential choice results in decisions that more closely approximate what people ‘really’ want. Copyright © 1999 John Wiley & Sons, Ltd.     

Personality predicts words in favorite songs

Psychologists have long theorized that people actively create, select, or modify experiences and situations to fulfill their individual psychological needs. However, little is known about how people may use forms of art and entertainment such as music to enhance their experiences and shape their environments for need satisfaction. In this research, we measured participants’ personality and the linguistic styles of their favorite songs, and observed significant associations between personality traits and linguistic cues in lyrics. These associations were stronger for participants who generally liked a song because of its lyrics rather than melody. Our study is the first to show how one’s personality is related to linguistic cues in someone else’s writings. It points to the possibility that people may like certain songs because the linguistic cues in the lyrics are congruent with their personality and hence can satisfy personal needs. This expands research on person-situation interaction and literature on personality and language use, and has important practical implications.