Chapter 7 Self-test questions

. Which of the following statements are correct? Please select all that apply.

Umwelt is that part of the environment which is perceived after sensory and central filtering.

The Umwelt concept was formulated by Jakob von Uexküll.

Releasing mechanisms can be conceptualized as filters that reduce the information from the physical environment to the animal's Umwelt.

Umwelt, as defined in ethology, encompasses the totality of the information present in the physical environment of an animal.

. Which of the following statements does not adequately describe supernormal stimuli?

Supernormal stimuli produce greater responses from an animal than do the natural sign stimuli.

When offered eggs of different sizes, oystercatchers prefer supernormal eggs.

The preference of oystercatchers for clutches with five eggs over normal clutches (which consist of three eggs) can be explained by the attractiveness of supernormal stimuli, as compared to the natural sign stimuli.

In humans, supernormal stimuli do not have any behavioral relevance.

. Which of the following statements characterizes best the relationship between releasers and motivation?

The effect of a releaser depends only on the stimulus properties but not on the motivation of the recipient.

Releasers have only immediate, releasing effects, but not tonic, motivational effects on the recipient.

The effect of a releaser depends on both the stimulus properties and the motivation of the recipient, and may include changes in both behavior and motivation of the recipient.

Absence of a behavioral change in an animal upon presentation of a releaser indicates the absence of any effect of this releaser on the recipient.

. Feature detection involves filtering of behaviorally irrelevant features of a complex sensory stimulus in order to extract behaviorally relevant features.

True

False

. Which of the following stimulus configurations defines unambiguously a 'worm' in the sensory world of toads?

An elongated object that moves in horizontal direction.

An elongated object that moves diagonally along its major axis.

An elongated object that moves vertically along its minor axis.

An elongated object that moves in vertical direction.

. Which of the following statements about the optic tectum and thalamic-prectal area is not correct?

Electrical stimulation of the optic tectum elicits various behavioral patterns characteristic of feeding behavior.

Electrical stimulation of the thalamic-pretectal area elicits escape responses.

Lesions of the thalamic-pretectal area result in decreased selectivity of the T5(2) neurons of the optic tectum.

The thalamic-pretectal area and the optic tectum operate independently of each other.

. Which of the following statements about the auditory system of barn owls is not correct?

Barn owls locate sound in the azimuth by analyzing interaural time differences.

Barn owls locate sound in the elevation by analyzing interaural intensity differences.

If barn owls directly face a source of sound, the sound intensities perceived by the left and right ears are identical.

If barn owls directly face a source of sound, they can localize this source equally well in the horizontal plane and in the vertical plane.

. Which of the following statements concerning the Lloyd Jeffress model are correct? Please select all that apply.

The computational model developed by Lloyd Jeffress provides an explanation for how the auditory system analyzes differences in the arrival times of sound at the two ears to estimate the direction of a source of sound in the azimuth plane.

According to the Jeffress model, asynchronous arrival of nerve impulses at coincidence detectors results in stronger firing of a given detector than synchronous arrival of such impulses.

In the Jeffress model, different coincidence detectors encode different interaural time differences.

Evidence for neural implementation of the Jeffress model has been obtained in the brain of barn owls, where neurons of the laminar nucleus serve as coincidence detectors, and axons arising from neuronal cells in the magnocellular nucleus function as delay lines.

. Which of the following statements about space-specific neurons in the acoustic system of barn owls is not correct?

In barn owls, space-specific neurons are found in the external nucleus.

Space-specific neurons respond to acoustic stimuli originating from the receptive field of these neurons.

Space-specific neurons respond selectively to specific combinations of interaural time and intensity differences.

The neural map formed by space-specific neurons is a linear representation of the auditory space in both azimuth and elevation.

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