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At least 667 records · Page 37Linked to original sources
PubMed2001

Cuttlefish camouflage: visual perception of size, contrast and number of white squares on artificial checkerboard substrata initiates disruptive coloration.

We investigated some visual background features that influence young cuttlefish, Sepia pharaonis, to change their skin patterning from 'general resemblance' of the substratum to disruptive coloration that breaks up their body form. Using computer-generated black/white checkerboard patterns as substrata, we first found that the size of the white squares had to be within a certain narrow range (relative to the size of the cuttlefish 'white square') for the animal to exhibit disruptive skin patterning. Second, given the appropriate size of checker, cuttlefish regulated their disruptive skin patterns according to the contrast between white and black squares. Third, by manipulating the number of white squares on a black background, we found that as few as four white squares among 316 black squares (or 1.25%) produced disruptive patterning, yet increasing the number of white squares to 20, 40 or 80 did not increase the frequency of appearance of the cuttlefish 'white square', but only its clarity of expression. These results demonstrate that the size, contrast and number of white objects in the surrounding substratum influence the production and expression of disruptive skin patterns in young cuttlefish.

Animals↗
PubMed1999

Visual perception: mind and brain see eye to eye.

Recent functional imaging studies have identified neural activity that is closely associated with the perception of illusory motion. The mapping of the mind onto the bin appears to be one-to-one: activity in visual 'motion area' MT is highly correlated with perceptual experience.

Brain↗
PubMed1981

Visual perception of lifted weight.

The weight of a box can be seen by observing another person lifting and carrying it. Evidence is provided in two experiments, the first of which employed videotaped events with the actor and box visible only as 21 bright patches. Observers judged the weight of the box rather linearly with an average slope of .87 and with a pooled standard deviation of 3.8 kg. The second experiment compared visual and haptic perception of box weight in similar events under conditions of live action. Average slopes of 1.00 in the visual mode and 1.20 in the haptic mode were obtained with standard deviations of 3.1 kg and 2.0 kg, respectively. It is concluded that the weight of the box, as a dynamic variable of the event, is well specified in the kinematic pattern and hence in the optic array. Furthermore, the visual system is efficient in picking up such information.

Cues↗
PubMed1982

An effective paradigm for conditioning visual perception in human subjects.

Repeated pairing of an auditory conditioned stimulus with a weak visual unconditioned stimulus produced extended image sequences and visual responses conditioned to the tone alone. The experiment is set into the context of Pavlov's view of Helmholtz's "unconscious inference" thus providing experimental evidence linking the higher mental process of perception with classical conditioning.

Adolescent↗