“Gaydar” is the ability to distinguish homosexual and heterosexual people using indirect cues. We investigated the accuracy of gaydar and the nature of “gaydar signals” conveying information about ...sexual orientation. Homosexual people tend to be more sex atypical than heterosexual people in some behaviors, feelings, and interests. We hypothesized that indicators of sex atypicality might function as gaydar signals. In Study 1, raters judged targets’ sexual orientation from pictures, brief videos, and sound recordings. Sexual orientation was assessed with high, though imperfect, accuracy. In Study 2, different raters judged targets’ sex atypicality from the same stimuli. Ratings of sexual orientation from Study 1 corresponded highly with targets’ self-reports of sex atypicality and with observer ratings of sex atypicality from Study 2. Thus, brief samples of sex-atypical behavior may function as effective gaydar signals.
Positive and negative stimuli have asymmetric fitness consequences. Whereas, a missed opportunity may be compensated, an unattended threat can be fatal. This is why it has been hypothesised that ...habituation to positive stimuli is fast while it may be difficult to habituate to negative stimuli, at least for primary (innate) stimuli. However, learning of secondary stimuli may delay the process of habituation. Here, we tested 64 weaned piglets in pairs. In three phases, lasting one week each, piglets were exposed five times to a stimulus of presumed negative, intermediate, or positive valence. Etho-physiological measurements of heart rate, heart rate variability, and general movement activity were collected during the last 4 min before the confrontation with the stimulus (anticipation phase). We found no consistent effect of the interaction between the valence of the stimuli and the repetition and a main effect of valence on our outcome variables. Therefore, we could neither support the hypothesis that piglets habituate more slowly to secondary positive stimuli than to primary negative stimuli nor that they habituate less to primary negative stimuli when compared with other stimuli. These results could have been caused because stimuli may not have differed in the presumed way, the experimental design may not have been adequate, or the measures were not suitable for detecting habituation to the stimuli. Based on the stimuli used here and their valence that was only presumed, we could not support the hypothesis that the habituation process differs according to the valence of the stimuli.
Stimuli are often presumed to be either negative or positive. However, animals' judgement of their negativity or positivity cannot generally be assumed. A possibility to assess emotional states in ...animals elicited by stimuli is to investigate animal preferences and their motivation to gain access to these stimuli. This study's aim was to assess the valence of social stimuli in sheep. We used silent videos of varying intensity of dogs as negative versus conspecifics as positive stimuli in three approaches: (1) an approach⁻avoidance paradigm; (2) operant conditioning using the video stimuli as reinforcers; and (3) an attention test. In the latter, we assessed differential attention of sheep to simultaneous projections by automatically tracking sheep head and ear postures and recording brain activity. With these approaches, it was difficult to support that the sheep's reactions varied according to the stimuli's presumed valence and intensity. The approach⁻avoidance paradigm and attention test did not support the assumption that dog videos were more negative than sheep videos, though sheep reacted to the stimuli presented. Results from the operant conditioning indicated that sheep were more prone to avoid videos of moving dogs. Overall, we found that standard video images may not be ideal to represent valence characteristics of stimuli to sheep.
Abstract With the aim of judging emotional valence from an animal's perspective, multiple physiological variables were recorded in sheep when they were exposed to situations likely to induce negative ...and positive emotional states. Fourteen sheep were conditioned for several weeks to anticipate the delivery of standard feed. In three experimental trials carried out thereafter, the animals' expectations regarding feed quality were either fulfilled by offering the familiar standard feed (control), frustrated by giving unpalatable wooden pellets (negative treatment) or surpassed by delivering enriched feed (positive treatment). Heart rate, root mean square successive difference (RMSSD), respiration rate, body-surface humidity, body-surface temperature and percentage of eye white were recorded prior to the delivery of feed (anticipation phase) and during the delivery (feeding phase) of either standard feed, wooden pellets or enriched feed. Data were analysed using linear mixed-effects models. Heart rate, respiration rate and variability of body-surface humidity were high during the delivery of wooden pellets and low during the feeding phases with standard and enriched feed; RMSSD showed an inverse pattern. In addition, heart rate was increased during the first feeding phase after the one with standard feed, independent of its presumed valence, whereas differential reactions were observed in the second feeding phase after standard feed. The results show that presumed negative and positive emotional states in sheep differ in their physiological reactions. Despite a need for validation in additional situations, the combination of heart rate, respiration rate, RMSSD and body-surface humidity appeared to be most useful for assessing physiological correlates of negative and positive emotional reactions in sheep.
Animals choose a course of action countless times each day. To do so, they need to prioritise their behaviour within a set of alternative actions and decide which of these actions to perform at any ...one time and for how long, that is, determine when the behaviour has reached its desired effect. This process has classically been called the proximate behavioural control mechanism. Several aspects contribute to this process: internal and external stimuli, the emotions that they elicit, motivation (wants), behavioural goals, valuation, decision‐making and its modulation by mood, and the assessment of behavioural outcomes (liking). I will address all these aspects in the form of an integrated conceptual model. In the process of behavioural control, options need to be valued, and I will refer to evidence showing that an affective hedonic process in respect to (future) reward and punishment heavily affects this value. Moreover, I view motivation, the force that finally drives a specific behavioural output, as being primarily influenced by affective states or even corresponding fully to them. Given the feedback in behavioural control by (dis‐)liking outcomes of behaviour, I reason that in respect to welfare it is more important for animals to reach proximate goals than to avoid negative stimuli. All behavioural choices are modulated, and I show how mood, a long‐term affective state, can cause such modulation. Proximate control of behaviour takes place in the brain, and I will briefly discuss how current and future brain research may elucidate how the brain computes these processes. Furthermore, the inclusion of affective states in the conceptual model raises the question of the subjective experience of animals, and I will address some of the important open questions in this area of research. I will conclude that neural studies cannot currently provide a detailed and general theory on the algorithms of proximate behavioural control. In parallel to further developing these approaches, I propose to strengthen a refined ethological approach with a focus on the states of “wanting” and “liking” in ecologically meaningful circumstances and with a strong ontogenetic (within species) and comparative (between species) component. I consider this ethological approach to be a highly promising step in understanding proximate behavioural control.
To minimise social conflicts between goats and improve pen design, knowledge of factors affecting social distances at the feeding rack is needed. In our study, we investigated the influence of the ...quality of social bonds, rank differences, grouping age and presence of horns on two types of social distances: (1) the distance goats choose freely at feeding when they have the option of keeping a large distance between each other; (2) the minimum distance possible without agonistic interactions if the goats are forced to feed in close proximity.
We used eight groups consisting of nine goats of different Swiss milking breeds and their crossbreeds that were kept in eight identical pens. Goats in four groups each either had horns or were hornless, and had been grouped either as juveniles or adults (2
×
2 factorial design). Information on social parameters (rank difference, quality of social bonds using the categories “amicable”, “neutral” and “antagonistic”) was collected for each dyad in the groups’ home pens. For each dyad within a group, we recorded the “freely chosen distance” at a 6-m-long hayrack (experiment 1) and the “individual distance” (=minimum distance possible in which no agonistic interactions occur) when two small mobile hayracks (one for each goat) were moved towards each other (experiment 2). The two types of social distances measured in the experimental situations were analysed using linear mixed-effects models.
The social distances in both experiments were significantly influenced by the quality of social bonds and age at grouping. Dyads with an amicable bond showed smaller distances than neutral or antagonistic dyads (experiment 1:
p
=
0.05, experiment 2:
p
=
0.001), and goats grouped as juveniles kept smaller distances apart than goats grouped as adults (
p
=
0.01 in both experiments). Rank differences and the presence of horns had no significant influence on the sizes of social distances. In conclusion, our results stress the importance of a sensible grouping management in goats aiming at grouping the animals early in ontogeny and keeping group composition stable.
Horses must lie down to go into vital rapid-eye movement (REM) sleep. If they are not lying down for sufficiently long periods they can become so sleep-deprived that they collapse uncontrollably, ...which results in a risk of injuries.
To investigate how recumbency as a prerequisite to REM sleep on the experimental days and the following nights was influenced by changes in social and spatial environment throughout the day.
Cross-over design in which subjects experienced each experimental condition twice.
Observations were conducted on a horse farm. Ten young horses in training were observed on days when they were alone indoors in a box, on an outdoor paddock alone, on the same paddock in pairs, and in the following night stabled alone. The number of lying bouts and the total lying duration throughout the day and night were assessed automatically using 3D-accelerometers and data were evaluated using mixed-models.
Horses had a higher number of lying bouts during the days (p = 0.05, by a factor of 1.21 95% CI: 1.00-1.45) and longer lying duration at night (p < 0.001, by a factor of 11.25 6.47-18.40). On average, the number of lying bouts and the duration of lying increased from being indoors alone, to being outdoors alone, and outdoors in pairs although this could not be statistically supported (bouts: p = 0.5, by a factor of 1.08 0.84-1.36 and 1.17 0.91-1.48; p = 0.6, duration: by a factor of 1.39 0.73-2.93 and 1.38 0.68-2.78).
A small number of horses were observed and there was large variability between days within horses.
We found some indications that open space and a social companion throughout the day increased time lying down in the day as well as during the following nights thus allowing for more REM sleep.
•Daily synchrony patterns in cows were observed.•Groups of cows differed in the amount of synchrony factors (feeding, milking).•Strongest synchrony was found in groups with weak synchrony ...factors.•Synchrony may therefore be a behavioural need for cows.
Synchrony is thought to provide fitness advantages to group-living animals, but little is known how animals maintain synchrony. We investigated intensity of synchrony factors (milking, feed-provision) in cattle herds. Intensity decreased from dairy cows milked in a parlour to cows milked by a robot to suckler cows raising calves. On 30 farms, 10 of each type, we recorded synchrony in lying and feeding. Peaks in lying synchronously were visible in the early morning, around noon, and late at night. These peaks decreased from the suckler cows to the cows milked in a parlour and to the cows milked by a robot. Complementary peaks were found for synchronous feeding. The asynchronous milking times with the milking robot decreased synchrony. Unexpectedly, the suckler cows with the weakest synchrony factors also showed a high level of synchrony. These results indicate that internal motivations for synchrony may be present in addition to external synchrony factors.
Horses can sleep while standing; however, recumbency is required for rapid eye movement (REM) sleep and therefore essential. Previous research indicated a minimal duration of recumbency of 30 min per ...24 h to perform a minimal duration of REM sleep. For group-housed horses, suitable lying area represents a potentially limited resource. In Switzerland, minimal dimensions for the space allowance of the littered area are therefore legally required. To assess the effect of different space allowances of the littered area on lying behavior, 38 horses in 8 groups were exposed to 4 treatments for 11 days each; T0: no litter provided, T0.5: 0.5× minimal dimensions, T1: minimal dimensions, and T1.5: 1.5× minimal dimensions. Non-littered areas were covered with hard rubber mats. Lying behavior was observed during the last 72 h of each treatment. The total number of lying bouts per 24 h was similar in treatments providing litter, whereas in treatment T0, recumbency occurred only rarely (
= 14.74,
= 0.0002) with the majority of horses lying down for less than 30 min per 24 h (Formula: see text,
= 0.0006). Overall, the total duration of recumbency per 24 h increased with increasing dimensions of the littered area, whereby the effect attenuated between treatment T1 and T1.5 in high-ranking horses but continued in low-ranking horses (
= 3.22,
= 0.076). Furthermore, low-ranking horses showed considerably more forcedly terminated lying bouts in treatments T0.5 and T1, but were similar to high-ranking horses in T1.5 (
= 8.43,
= 0.005). Nonetheless, a number of individuals showed durations of recumbency of less than 30 min per 24 h even in treatment T1.5. The lying behavior was dependent on the availability of a soft and deformable surface for recumbency. A beneficial effect of enlarged dimensions of the littered area was shown by increased durations of recumbency and decreased proportion of forcedly terminated lying bouts in low-ranking horses. Taking this into account, it became evident that the minimal dimensions for the littered area as implemented in the Swiss animal welfare legislation do not ensure undisturbed lying behavior for all members of a given group.
•Time estimation ability of dry sows were investigated.•Intervals of minutes and days were considered.•At the end of an interval lasting few minutes slight changes in heart rate occurred.•Sows learnt ...to correctly choose a high food reward every fifth day.•Time estimation in the range of minutes was weaker than in the range of days.
Time estimation helps allocating time to different tasks and to plan behavioural sequences. It may also be relevant to animal welfare if it enables animals assessing the duration of a negative situation. Here, we investigated the ability of dry sows to estimate short and long time periods. We used a variant of the peak-interval procedure and the choice between 2 resources of different quality and replenishment rates to assess time periods in the order of minutes and days, respectively. In the minute-experiment, the sows were trained to expect an interruption while feeding at the end of an interval. Heart rate and heart rate variability slightly and continuously increased and decreased, respectively, towards the end of that interval. In the day-experiment, lasting about 60days, the sows were increasingly more likely to open the door to a high food reward on the correct day when this food reward was presented every fifth day. We conclude that the sows learnt to estimate time intervals of 5days after lengthy training but did not accurately learn intervals in the range of minutes. Therefore, they might re-visit replenishing resources after several days, but may not base short-term decisions solely on the passing of time.
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