Preference for biological motion in domestic chicks: sex-dependent effect of early visual experience

To examine the effects of early visual experience on preference for biological motion (BM), newly hatched chicks were exposed to a point-light animation (a visual stimulus composed of identical light points) depicting the following features of a hen: a walking hen (a BM stimulus), a rotating hen (a non-BM stimulus), a pendulum stimulus, a random motion stimulus and a stationary pattern. Chicks were then tested in a binary choice task, choosing between walking-hen and rotating-hen stimuli. Males exhibited a preference for BM if they had been trained with any animation except the stationary pattern stimulus, suggesting that the BM preference was not learned, but induced by motion stimuli. We found a significant positive correlation between the number of approaches in training and the preference in the test, but locomotion alone did not cause preference for BM. In contrast, females exhibited a particularly strong preference for walking-hen stimuli, but only when they had been trained with it. Furthermore, females (but not males) trained with random motion showed a preference for walking hen over walking cat (a biological motion animation depicting a cat), possibly suggesting that females are choosier than males. Chicks trained with a stationary pattern and untrained controls did not show a significant preference. The induction of BM preference is discussed in terms of possible ecological background of the sex differences.     

Auditory versus visual processing of three sets of simultaneous digit pairs.

Two experiments were conducted to determine whether the auditory and visual systems process simultaneously presented pairs of alphanumeric information differently. In Experiment 1, different groups of subjects were given extensive practice recalling pairs of superimposed visual or auditory digits in simultaneous order (the order of arrival) or successive order (one member of each digit pair in turn, followed by the other pair member). For auditory input, successive order of recall was more accurate, particularly for the last two of three pairs presented, whereas for visual input, simultaneous order of recall was more accurate. In Experiment 2, subjects were cued to recall in one or the other order either immediately before or after stimulus input. Recall order results were the same as for Experiment 1, and precuing did not facilitate recall in either order for both modalities. These results suggest that processing in the auditory system can only occur successively across time, whereas as in the visual system processing can only occur simultaneously in space.     

Two channels for flicker in the human visual system

The human visual system contains a large number of narrowly-tuned spatial-frequency-specific channels. Does it contain an analogous set of channels tuned to a narrow range of temporal frequency? On the basis of data gathered with the use of a threshold elevation technique it is argued that human sensitivity to flicker can be accounted for by assuming the existence of just two filters, one a low-pass filter peaking gently at around 6 Hz and one a band-pass filter peaking at around 9 Hz. Similar data gathered from studies of interocular transfer suggest that at least some of the mechanisms involved are binocular, rather than being purely monocular as has previously been suggested.     

Origins of the proprioceptive function of vision: visual control of posture in one day old domestic chicks.

Recently hatched domestic chicks control their upright bipedal posture, at least in part, with respect to the flow of visual information at the retina, as do human infants when they first acquire control of the head, of sitting, and of standing. Some implications of the similarity of the proprioceptive function of vision in chicks and in humans for the origins and development of postural control are discussed.     

Effects of fasting on visual flicker fusion

Two experiments are reported which investigated the effects of fasting on visual flicker fusion (VFF). In Exp. 1 the VFF of 40 undergraduate students, 20 men and 20 women, whose mean age was 22.5 yr., was measured in nonfasting conditions 1 to 2 weeks before and in fasting conditions during the Muslim fasting month of Ramadan. In Exp. 2 the VFF of a comparable group of 15 men and 15 women, whose mean age was 23.2 yr., was measured in a different month in both fasting and nonfasting conditions. Subjects were assigned randomly to these two conditions. Analysis shows that fasting reduced VFF significantly in both experiments. This finding indicates that fasting is likely to reduce perceptual sensitivity. The results were explained in terms of fatigue and physical exhaustion effects produced by fasting.     

Task-irrelevant visual motion and flicker attenuate the attentional blink

Our reduced ability to correctly report two sequentially presented targets is seen in the robust effect known as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992). One recent report (Olivers & Nieuwenhuis, 2005) strikingly reveals the AB to be virtually abolished when non-task-demanding music occurs in the background. The authors suggest that a diffuse attentional state is the mediating factor. Here, we seek to broaden the finding’s generality by determining if task-irrelevant visual motion and flicker also attenuate the AB. In our experiments, the AB task was presented together with a background field of moving dots that could moveaway from ortoward the central AB task, or flicker. In the control condition, the dots remained static. The AB was attenuated—though to different degrees—in all experimental conditions, but not in the static condition. Our findings add to the generality of the previous conclusions, and we emphasize an account based on the overallocation of attention.     

Changes in critical flicker frequency during prolonged visual deprivation

Subjects were tested on the critical flicker frequency during a 1-week period of visual deprivation (either homogeneous illumination or darkness). Deprived subjects showed no significant differences from a confined control group. Results were discussed in relation to previous research, Schultz’s theory of “sensoristasis” and Sharpless’ revision of the “law of denervation.”     

Auditory and visual factors of intelligence

In a sample of 241 convicts, most of whom were between 20 and 35 years of age, a sample of 18 primary mental abilities was factored to explore the idea that in performances that are believed to indicate human intelligence there are organizations among visual and auditory functions that operate independently from the relation-perceiving and correlate-educing functions of fluid and crystallized intelligence. Objectively rotated results suggest that, indeed, reliable overlapping (common-factor) functions of Auditory Acuity (Ac), Auditory Organization (Ga), Visual Organization (Gv), Acculturational Eduction (Gc) and Fluid Eduction (Gf) represent separate components of individual differences in performances on intellectual tasks broadly conceived.     

Auditory coding of visual patterns for the blind

Recognition tasks of simple visual patterns have been used to assess an early visual--auditory sensory-substitution system, consisting of the coupling of a rough model of the human retina with an inverse model of the cochlea, by means of a pixel-frequency relationship. The potential advantage of the device, compared with previous ones, is to give the blind the ability to both localise and recognise visual patterns. Four evaluation sessions assessed the performance of twenty-four blindfolded sighted subjects using the device. Subjects had to recognise twenty-five visual patterns, one at a time, using a head-mounted small camera and interpreting the corresponding sounds given by the device. Half the subjects were trained by means of a correction feedback procedure during ten one-hour training sessions embedded in between the evaluation sessions. Results revealed extremely successful training effects. Performance of trained subjects significantly increased with practice compared with the untrained control group. The improvement was also observed for new patterns, demonstrating a learning-process generalisation. The negative correlation observed between scores and processing time showed that the subjects' response accuracy was related to their speed. In conclusion, simple pattern recognition is possible with a fairly natural vision-to-audition coding scheme, given the possibility for the subjects to have sensory--motor interactions while using the device.     

Auditory and visual differences in time perception

The present experiment assessed intersensory differences in temporal judgments, that is, auditory stimuli are perceived as longer than physically equivalent visual stimuli. The results confirmed the intersensory difference. Auditorially defined intervals were experienced as longer than visually defined intervals. Auditory boundaries were perceived as longer than visual ones. An interaction of boundary modality and interval modality was obtained which suggested that auditorially defined intervals provided more temporal information about events occurring in close temporal proximity than visually defined intervals. It was hypothesized that cognitive factors, specifically stimulus complexity, would affect the auditory and visual systems differentially. This hypothesis was not substantiated, although highly complex stimuli were experienced as longer than those of low complexity.     

Spontaneous generalization of abstract multimodal patterns in young domestic chicks

From the early stages of life, learning the regularities associated with specific objects is crucial for making sense of experiences. Through filial imprinting, young precocial birds quickly learn the features of their social partners by mere exposure. It is not clear though to what extent chicks can extract abstract patterns of the visual and acoustic stimuli present in the imprinting object, and how they combine them. To investigate this issue, we exposed chicks (Gallus gallus) to three days of visual and acoustic imprinting, using either patterns with two identical items or patterns with two different items, presented visually, acoustically or in both modalities. Next, chicks were given a choice between the familiar and the unfamiliar pattern, present in either the multimodal, visual or acoustic modality. The responses to the novel stimuli were affected by their imprinting experience, and the effect was stronger for chicks imprinted with multimodal patterns than for the other groups. Interestingly, males and females adopted a different strategy, with males more attracted by unfamiliar patterns and females more attracted by familiar patterns. Our data show that chicks can generalize abstract patterns by mere exposure through filial imprinting and that multimodal stimulation is more effective than unimodal stimulation for pattern learning.     

Similarity of approach and pecking preferences for spectral stimuli in domestic chicks: absence of a mirror-image relation.

The results of Schaefer and Hess showing that White Rock chicks described mirror-image response functions to spectral stimuli in approach and pecking behavior could not be replicated using Cornish-Cross chicks under more controlled conditions. Our results showed similar blue-orange bimodal functions for both behavioral responses, resembling the approach data of Schaefer and Hess and the earlier pecking data of Hess and others, but not the pecking data reported by Schaefer and Hess.