Duration Of Looks Research Articles

Eye preferences in capuchin monkeys (Sapajus apella).

This study explored whether capuchin monkey eye preferences differ systematically in response to stimuli of positive and negative valence. The 'valence hypothesis' proposes that the right hemisphere is more dominant for negative emotional processing and the left hemisphere is more dominant for positive emotional processing. Visual information from each eye is thought to be transferred faster to and primarily processed by the contralateral cerebral hemisphere. Therefore, it was predicted capuchin monkeys would show greater left eye use for looking at negative stimuli and greater right eye use for looking at positive stimuli. Eleven captive capuchin monkeys were presented with four images of different emotional valence (an egg and capuchin monkey raised eyebrow face were categorised as positive, and a harpy eagle face and capuchin monkey threat face were categorised as negative) and social relevance (consisting of capuchin monkey faces or not), and eye preferences for viewing the stimuli through a monocular viewing hole were recorded. While strong preferences for using either the left or right eye were found for most individuals, there was no consensus at the population level. Furthermore, the direction of looking, number of looks and duration of looks did not differ significantly with the emotional valence of the stimuli. These results are inconsistent with the main hypotheses about the relationship between eye preferences and processing of emotional stimuli. However, the monkeys did show significantly more arousal behaviours (vocalisation, door-touching, self-scratching and hand-rubbing) when viewing the negatively valenced stimuli than the positively valenced stimuli, indicating that the stimuli were emotionally salient. These findings do not provide evidence for a relationship between eye preferences and functional hemispheric specialisations, as often proposed in humans. Additional comparative studies are required to better understand the phylogeny of lateral biases, particularly in relation to emotional valence.

Physiological and Behavioral Responses Reveal 9-Month-Old Infants’ Sensitivity to Pleasant Touch

Caregiving touch has been shown to be essential for the growth and development of human infants. However, the physiological and behavioral mechanisms that underpin infants’ sensitivity to pleasant touch are still poorly understood. In human adults, a subclass of unmyelinated peripheral nerve fibers has been shown to respond preferentially to medium-velocity soft brushing. It has been theorized that this privileged pathway for pleasant touch is used for close affiliative interactions with conspecific individuals, especially between caregivers and infants. To test whether human infants are sensitive to pleasant touch, we examined arousal (heart rate) and attentional engagement (gaze shifts and duration of looks) to varying velocities of brushing (slow, medium, and fast) in 9-month-old infants. Our results provide physiological and behavioral evidence that sensitivity to pleasant touch emerges early in development and therefore plays an important role in regulating human social interactions.

Peep to pilfer: what scrub-jays like to watch when observing others

Food caching is accompanied by a risk of theft, especially when observers remember cache locations and pilfer them later. This is the case in some corvids, in which cachers have been shown to change their behaviour flexibly to prevent and reduce the quality of information available to observers who might steal their caches, and invalidate information those observers have already obtained. In this ‘war of information’, strategies that observers use to increase the amount and validity of information about caches have been studied much less. A first step in exploring pilferer strategies is to determine what individuals prefer to watch when observing others. To that end, we allowed western scrub-jays, Aphelocoma californica, to observe either of two cages through peepholes, varying the information available in them in four experimental conditions. We later extracted the number and duration of looks into each peephole and the behaviour of the individuals that were observed through them. Jays spent much more time looking at caching individuals than either at noncaching individuals or at a cage with only a food bowl and caching trays, suggesting the birds prefer to watch caching and cache-related behaviours. Moreover, when we analysed the attention-getting and attention-holding aspects separately, our results suggested that jays are specifically tuned to looking at locations where there is high potential for caching. Improved pilfering success associated with such active information seeking by observers may have forced cachers to evolve better strategies for concealing or invalidating caching information, in a coevolutionary process resulting in the sophisticated strategies some corvids use.

Monitoring with Head-Mounted Displays in General Anesthesia

Patient monitors in the operating room are often positioned where it is difficult for the anesthesiologist to see them when performing procedures. Head-mounted displays (HMDs) can help anesthesiologists by superimposing a display of the patient's vital signs over the anesthesiologist's field of view. Simulator studies indicate that by using an HMD, anesthesiologists can spend more time looking at the patient and less at the monitors. We performed a clinical evaluation testing whether this finding would apply in practice. Six attending anesthesiologists provided anesthesia to patients undergoing rigid cystoscopy. Each anesthesiologist performed 6 cases alternating between standard monitoring using a Philips IntelliVue MP70 and standard monitoring plus a Microvision Nomad ND2000 HMD. The HMD interfaced wirelessly with the MP70 monitor and displayed waveform and numerical vital signs data. Video was recorded during all cases and analyzed to determine the percentage of time, frequency, and duration of looks at the anesthesia workstation and at the patient and surgical field during various anesthetic phases. Differences between the display conditions were tested for significance using repeated-measures analysis of variance. Video data were collected from 36 cases that ranged from 17 to 75 minutes in duration (median 31 minutes). When participants were using the HMD, compared with standard monitoring, they spent less time looking toward the anesthesia workstation (21.0% vs 25.3%, P = 0.003) and more time looking toward the patient and surgical field (55.9% vs 51.5%, P = 0.014). The HMD had no effect on either the frequency of looks or the average duration of looks toward the patient and surgical field or toward the anesthesia workstation. An HMD of patient vital signs reduces anesthesiologists' surveillance of the anesthesia workstation and allows them to spend more time monitoring their patient and surgical field during normal anesthesia. More research is needed to determine whether the behavioral changes can lead to improved anesthesiologist performance in the operating room.

Speed vs. thoroughness in infant visual information processing

The relation between speed and cognition is assuming an increasingly prominent position in infant research. The current study examined the potential trade-off between speed of processing, as measured by learning rate and the duration of individual looks, and thoroughness of processing, as measured by the extraction of stimulus detail. Six and one-half month old infants learned to distinguish a familiar face from a series of faces with novel features and were then shown faces which probed their knowledge of the familiar features, in particular their ability to discern subtle changes in these features. Learning rate showed a clear relation to performance on the probe task, but duration of looks showed none. Infants who took longer to learn discriminated between faces with the familiar features and variants with only one or two novel features, whereas those who learned quickly did not. The findings suggest that, at least in some situations, infants who process information slowly may actually extract more detail.

Visual attention in infant monkeys: Effects of dietary fatty acids and age.

Effects of dietary essential fatty acids on visual attention were explored longitudinally in infant rhesus monkeys with a visual paired-comparison paradigm. Sets of primate faces and of patterns were presented at Weeks 2, 5, 9, and 13 to 9 infants deficient in omega-3 fatty acids and 8 fed a standard nursery diet. Familiarization to 1 member of each pair preceded simultaneous presentation of both stimuli. Infants fed the deficient diet showed longer individual looks in both immediate and 24-hr tests. Duration of looks decreased with age to familiar but not to novel stimuli. The proportion of time looking at the novel stimulus (% novel) increased with age but was not affected by diet. Look duration and % novel were differentially affected and may reflect different underlying processes.

Visual attention in infant monkeys: Effects of dietary fatty acids and age.

Effects of dietary essential fatty acids on visual attention were explored longitudinally in infant rhesus monkeys with a visual paired-comparison paradigm. Sets of primate faces and of patterns were presented at Weeks 2, 5, 9, and 13 to 9 infants deficient in omega-3 fatty acids and 8 fed a standard nursery diet. Familiarization to 1 member of each pair preceded simultaneous presentation of both stimuli. Infants fed the deficient diet showed longer individual looks in both immediate and 24-hr tests. Duration of looks decreased with age to familiar but not to novel stimuli. The proportion of time looking at the novel stimulus (% novel) increased with age but was not affected by diet. Look duration and % novel were differentially affected and may reflect different underlying processes.

Tactual habituation and discrimination of form in infancy: a comparison with vision.

Tactual discriminative abilities out of the control of vision are studied in 5-month-old infants, and compared with their visual discriminative abilities. The relevance of a habituation/reaction to novelty procedure in the tactual modality is tested. An infant control procedure is used in both modalities on 2 independent samples of 32 infants each. Habituation and discrimination occur tactually as well as visually, the duration of holds decreasing more than the duration of looks. Accumulated holding time is 3 times longer than accumulated looking time. Analogies and discrepancies between tactual and visual habituations are discussed, and the problem of sensory dominance is raised. Such results are basic to studies on cross-modal transfer, from vision to touch as well as from touch to vision.

Tactual Habituation and Discrimination of Form in Infancy: A Comparison with Vision

Tactual discriminative abilities out of the control of vision are studied in 5-month-old infants, and compared with their visual discriminative abilities. The relevance of a habituation/reaction to novelty procedure in the tactual modality is tested. An infant control procedure is used in both modalities on 2 independent samples of 32 infants each. Habituation and discrimination occur tactually as well as visually, the duration of holds decreasing more than the duration of looks. Accumulated holding time is 3 times longer than accumulated looking time. Analogies and discrepancies between tactual and visual habituations are discussed, and the problem of sensory dominance is raised. Such results are basic to studies on cross-modal transfer, from vision to touch as well as from touch to vision.