Effect of electric shock on rats' activity in familiar and unfamiliar environments

It is found that electric shock delivered before exposure to a Y-maze reduces the activity of rats whether the maze is familiar or unfamiliar. Increasing familiarity with the maze reduces activity for shocked and unshocked rats. It is argued that this finding presents difficulties for theories according to which exploratory behaviour depends on fear.     

Self-face advantage over familiar and unfamiliar faces: A three-level meta-analytic approach

Despite the increasing number of researchers interested in self-face, so far, no study has summarized the behavioral findings that contribute to the debate on self-face advantage. Most studies have focused on neural correlates of the self, although functional uniqueness can also be considered an important criterion for determining whether a stimulus is unique. The present meta-analysis systematically compared reaction time (RT) responses for self-face with other face identities across 54 studies. Different moderator factors were tested: familiarity, identity, head angle, laterality, and culture. We used a three-level meta-analytic approach, which is the best approach to account for the dependency of effect sizes. Results showed a significant (Hedges’s g_av = ?0.298) effect size, indicating faster RT for self-face than for other faces in general. Except for culture, none of the moderators employed significantly impacted on the main effect. Regarding culture, results showed that participants from Western cultures tend to respond faster to their own face than to other people’s faces, while for participants from Eastern cultures, the effect was not significant. In summary, our results indicate that the self-face benefits from an advantage in terms of reaction time and may be considered a unique stimulus. Implications and limitations of the results are discussed.     

Effects of familiar and unfamiliar asynchronous music on treadmill walking endurance

To assess effects of familiarity of music on treadmill endurance, 15 female undergraduates in sports science performed an incremental treadmill walking task on three separate occasions while listening to Familiar Music, Unfamiliar Music, and White Noise. A repeated-measures analysis of variance indicated that participants walked for significantly longer when accompanied by Familiar and Unfamiliar Music in comparison to White Noise (p<.01). Although participants rated Familiar Music as significantly more motivating than Unfamiliar music (p<.05), no significant differences were found between the two music conditions for treadmill endurance. Heart rates did not appear to be influenced by music during treadmill walking or on completion of the task.     

The effects of active choice,shock duration,shock experience,and probability on the choice between immediate and delayed shock

The choice between immediate and delayed shock was investigated in three experiments with college students. Some Ss were required to choose between a longer-duration shock immediately and a shorter-duration shock later. Immediate, as opposed to delayed, choices were more frequent when: (a) Ss were required to choose the immediate or the delayed shock in contrast to other procedures in which Ss were required to choose immediate shock or passively wait for automatic shock to occur, (b) the duration of the immediate shock was reduced, (c) the S was given prior experience with shock, and (d) the probability of the immediate shock was reduced. Under some circumstances, shock delay and anxiety increased the frequency of immediate choices.     

Evidence that rats discriminate between familiar and unfamiliar putative urinary odorants of adult male conspecifics

Adam [1976; Lehman and Adams, 1977] suggested that a resident rat makes an olfactory comparison of cage odor and other rat odor prior to attacking an unfamiliar conspecific intruder. The findings of the present study are consistent with the notion that rats discriminate between familiar and unfamiliar putative urinary odorants Adult male albino rats were tested for preferences between areas treated with familiar urine (11 hours pretest exposure), unfamiliar urine (no pretest exposure), and untreated areas. Subjects (N = 12) preferred areas treated with familiar urine over ones treated with unfamiliar urine (p < 0.05). Also, they (N = 12 per preference-test group) preferred areas treated with either urine over untreated ones (familiar versus clean, p < 0.01; unfamiliar versus clean, p < 0.05).     

A temporal parameter influencing choice between signalled and unsignalled shock schedules

The present study investigated whether choice of a signalled variable-time shock schedule over an unsignalled one was influenced by the average intershock interval. Eight rats were given a choice between signalled and unsignalled shock schedules in a series of conditions with average intershock intervals of 510, 270, 150, 90, 60, and 45 sec. Each test condition was preceded by a training-baseline condition, and schedule values were arranged in an ascending (four subjects) or descending (four subjects) order. Choice of the signalled conditions was directly related to the average intershock interval of the variable-time schedule for six of the eight subjects. The per cent of time in the signalled condition was highest when the average intershock interval was 150 sec or longer and lowest when the average intershock interval was 45 sec. The findings were interpreted as being due to changes in the safety features of the signalled schedule, rather than to changes in the average intershock interval per se.     

Anticipation of electric shock: A psychophysical study

Successive measures of emotional intensity were obtained by a two-step scaling procedure from 23 subjects anticipating an electric shock to be given at the end of a 45-min period. Half of Ss had a clock available, while the other half had to estimate apparent time. The emotional reaction was shown to increase exponentially as time before shock decreased. Heart rate also increased as time for shock was approaching, but the trend was not regular.     

Identification of familiar and unfamiliar faces from internal and external features: some implications for theories of face recognition

Three experiments are reported in which recognition of faces from whole faces or internal or external features was compared. In the first experiment, where the faces were of famous people, an advantage was found for identification from internal features. In the second experiment involving unfamiliar faces, however, no difference was found in recognition rates when subjects were given the internal or the external features. In a third experiment famous faces were presented and mixed with other famous faces for a recognition test. As in experiment 1, better recognition occurred from internals as compared with external features. It is argued that the internal representation for familiar faces may be qualitatively different from that for face seen just once. In particular some advantage in feature saliency may accrue to the internal or 'expressive' features of familiar faces. The implications of these results are considered in relation to general theories of face perception and recognition.     

Comparisons between variable-interval and fixed-interval schedules of electric shock delivery

Responding maintained in rats under a variable-interval 35-sec food schedule was suppressed more by 60-sec and 240-sec fixed-interval schedules of shock delivery than by 60-sec and 240-sec variable-interval schedules of shock delivery. When the delivery of shock was preceded by a 5-sec visual stimulus, little overall response suppression was found with either fixed-interval or variable-interval schedules. In a third experiment, the percentage of occasions on which a cue preceded each shock delivery was varied from 0% to 100%. For the fixed-interval shock condition, the most suppression occurred with the 0% treatment, the least with 100%, and an intermediate amount with the 50% treatment. For the variable-interval groups, the most suppression occurred in the 50% condition, the least in the 100% group, and an intermediate amount with 0%.     

Effects of prior agonistic experience on risk assessment and approach behavior evoked by familiar or unfamiliar conspecific odors

Risk assessment and appetitive behaviors in response to familiar and unfamiliar conspecific odors were measured in mice rendered dominant or subordinate by a series of resident-intruder encounters. Subordinate mice showed elevated levels of risk assessment in response to the odors of both familiar dominant and unfamiliar males. These behaviors were almost totally absent among dominant males exposed to familiar subordinate or unfamiliar male odors. Subordinate mice showed a marginally significant elevation in latencies to approach familiar, but not unfamiliar, dominant odors. Dominant and subordinate mice spent comparable amounts of time in the cage area containing familiar antagonist odors, however, and the durations of subordinates were mildly elevated, rather than decreased, when unfamiliar conspecific odors were present. There were no group differences in any of the appetitive behaviors. These findings suggest that apparent preferences for conspecific odors may arise from quantitatively and/or qualitatively differing emotional states. The inclusion of risk assessment measures is suggested to be a useful adjunct for studies of olfactory preference/rejection. © 1994 Wiley-Liss, Inc.     

The effect of facial expression and gaze direction on memory for unfamiliar faces

We report data from an experiment that investigated the influence of gaze direction and facial expression on face memory. Participants were shown a set of unfamiliar faces with either happy or angry facial expressions, which were either gazing straight ahead or had their gaze averted to one side. Memory for faces that were initially shown with angry expressions was found to be poorer when these faces had averted as opposed to direct gaze, whereas memory for individuals shown with happy faces was unaffected by gaze direction. We suggest that memory for another individual's face partly depends on an evaluation of the behavioural intention of that individual.     

The emotional impact of faces (but not names): Face specific changes in skin conductance responses to familiar and unfamiliar people

Skin Conductance Responses (SCRs) to familiar and unfamiliar names and faces were recorded from independent groups of subjects, using two different presentation designs: the first employing fewer familiar than unfamiliar items (Tranel, Fowles, and Damasio, 1985) and the second employing equal numbers of familiar and unfamiliar items. In both designs, familiar faces were responded to significantly more strongly than unfamiliar faces, whereas for names there was no difference in responses to familiar and unfamiliar stimuli. Faces produced significantly larger overall SCRs than names in the unequal familiar/unfamiliar ratio design, but this effect was not observed in the equal ratio design. The results are discussed with particular reference to those previously published by Tranel et al. (1985) and in relation to work both on covert recognition in prosopagnosia and on one of the delusional misidentification syndromes known as the Capgras delusion. This study was carried out with generous support from the EJLB Foundation (Canada) and the Wellcome Trust.     

The emotional impact of faces (but not names): Face specific changes in skin conductance responses to familiar and unfamiliar people

Skin Conductance Responses (SCRs) to familiar and unfamiliar names and faces were recorded from independent groups of subjects, using two different presentation designs: the first employing fewer familiar than unfamiliar items (Tranel, Fowles, and Damasio, 1985) and the second employing equal numbers of familiar and unfamiliar items. In both designs, familiar faces were responded to significantly more strongly than unfamiliar faces, whereas for names there was no difference in responses to familiar and unfamiliar stimuli. Faces produced significantly larger overall SCRs than names in the unequal familiar/unfamiliar ratio design, but this effect was not observed in the equal ratio design. The results are discussed with particular reference to those previously published by Tranel et al. (1985) and in relation to work both on covert recognition in prosopagnosia and on one of the delusional misidentification syndromes known as the Capgras delusion. This study was carried out with generous support from the EJLB Foundation (Canada) and the Wellcome Trust.     

Lateralised processing of the internal and the external facial features of personally familiar and unfamiliar faces: a visual half-field study

In this visual half field (VHF) experiment, we investigated possible differences between the left and the right hemisphere in the processing of the internal and external features of familiar and unfamiliar faces. Previous studies using famous and unknown faces had indicated that both hemispheres use the same qualitative mode of processing with the internal features being more important for the perception of familiar faces. In this experiment, personally familiar faces rather than famous faces are used. There are several, mainly methodological, reasons why personally familiar faces are more appropriate stimuli to investigate face processing. The results of the present study showed that no overall visual field effect occurred, but more importantly, that face processing in the left hemisphere differed qualitatively from that in the right hemisphere. The theoretical repercussions of these findings are discussed.     

The effect of choice on intention-behavior consistency

Three studies were conducted with the aim of investigating whether choice of behavioral alternative increases intention-behavior consistency. In Study 1 undergraduates were asked to write and mail back an essay on a topic they either chose or were assigned. Demonstrating an effect of choice, significantly more subjects who chose an essay topic mailed back the essays. These subjects also rated their intention to write the essay as stronger, thus suggesting that the difference between choice and no choice is that the intention is self-generated. Supporting this interpretation, no differences in mail-back rates were observed in Studies 2 and 3 between a difficult and easy choice condition. Furthermore, an alternative hypothesis that choice induces implementation intentions did not receive support since independent effects were in Study 2 found of deciding when and where to write the essay and in Study 3 of making an outline of the essay.