Hand Preferences in Olive Baboons (Papio anubis) During Cognitive Performance on Match-to-Sample Tasks and Natural Behaviors.

An individual shows handedness when they consistently prefer one hand over the other for tasks that can be performed with either hand. Humans have a population-level right-hand preference, and past research shows that a variety of nonhuman primate species also show hand preferences. More complex manual tasks elicit stronger hand preferences than less complex manual tasks, but not much is known about hand preferences during a cognitive task in nonhuman primates.

Visual Perception of Photographs of Rotated 3D Objects in Goldfish ().

This study examined goldfishes' ability to recognize photographs of rotated 3D objects. Six goldfish were presented with color photographs of a plastic model turtle and frog at 0° in a two-alternative forced-choice task. Fish were tested with stimuli at 0°, 90°, 180°, and 270° rotated in the picture plane and two depth planes.

How humans discriminate acoustically among bottlenose dolphin signature whistles with and without masking by boat noise.

Anthropogenic noise in the world's oceans is known to impede many species' ability to perceive acoustic signals, but little research has addressed how this noise affects the perception of bioacoustic signals used for communication in marine mammals. Bottlenose dolphins (Tursiops truncatus) use signature whistles containing identification information. Past studies have used human participants to gain insight into dolphin perception, but most previous research investigated echolocation.

Visual perception in a bottlenose dolphin (Tursiops truncatus): Successful recognition of 2-D objects rotated in the picture and depth planes.

Aquatic species such as bottlenose dolphins can move in 3 dimensions and frequently view objects from different orientations. This study examined their ability to identify 2-D objects visually despite changes in orientation across 2 rotation planes. A dolphin performed a matching-to-sample task in which a sample was presented at a different orientation from its match in a 3-alternative choice array.

North American river otters (Lontra canadensis) discriminate between 2D objects varying in shape and color.

We investigated the ability of North American river otters (Lontra canadensis) to visually discriminate between 2D objects. The otters learned to discriminate between stimuli using multiple visual features and then were tested with stimuli in which one of the features was eliminated (color or shape). Two adult otters were trained in a two-alternative forced choice task to discriminate between a red circle and a blue triangle.

Small and large number discrimination in goldfish (Carassius auratus) with extensive training.

Previous studies on relative quantity discrimination in birds and mammals with training procedures have employed hundreds or thousands of trials whereas studies with fish typically use dozens of trials. The goal of this study was to examine whether more extensive training improves the performance of fish tested on stimuli in the small (<4) and large (>4) number range. Goldfish were trained with dot array stimuli using the ratio 0.

Recognition of Frequency Modulated Whistle-Like Sounds by a Bottlenose Dolphin (Tursiops truncatus) and Humans with Transformations in Amplitude, Duration and Frequency.

Bottlenose dolphins (Tursiops truncatus) use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin's (Tursiops truncatus) ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A) in response to a specific sound (sound A) for a total of three object-sound associations.

The ability to recognize objects from bottlenose dolphin (Tursiops truncatus) echoes generalizes across multiple orientations in humans and neural networks.

Object constancy, the ability to recognize objects despite changes in orientation, has not been well studied in the auditory modality. Dolphins use echolocation for object recognition, and objects ensonified by dolphins produce echoes that can vary significantly as a function of orientation. In this experiment, human listeners had to classify echoes from objects varying in material, shape, and size that were ensonified with dolphin signals.

Changes in consistency patterns of click frequency content over time of an echolocating Atlantic bottlenose dolphin.

Echolocation clicks were recorded from an Atlantic bottlenose dolphin Tursiops truncatus trained to discriminate frequency filtered phantom targets in 1998 and in 2004. These clicks showed consistency within their spectra intensity profiles but only in a certain band of frequencies. In 2004 almost all the clicks were consistent within the 0-42 kHz band regardless of the presented target or the click source level.

Interpulse interval modulation by echolocating big brown bats (Eptesicus fuscus) in different densities of obstacle clutter.

Big brown bats (Eptesicus fuscus) use biosonar to find insect prey in open areas, but they also find prey near vegetation and even fly through vegetation when in transit from roosts to feeding sites. To evaluate their reactions to dense, distributed clutter, bats were tested in an obstacle array consisting of rows of vertically hanging chains. Chains were removed from the array to create a curved corridor of three clutter densities (high, medium, low).

Detection of targets colocalized in clutter by big brown bats (Eptesicus fuscus).

Echolocating big brown bats (Eptesicus fuscus) frequently catch insects during aerial pursuits in open spaces, but they also capture prey swarming on vegetation, and from substrates. To evaluate perception of targets on cluttered surfaces, big brown bats were trained in a two-alternative forced-choice task to locate a target, varying in height, that was embedded partway in holes (clutter) cut in a foam surface. The holes were colocalized with the possible positions of the target at distances ranging from 25 to 35 cm.

Evidence for spatial representation of object shape by echolocating bats (Eptesicus fuscus).

Big brown bats were trained in a two-choice task to locate a two-cylinder dipole object with a constant 5 cm spacing in the presence of either a one-cylinder monopole or another two-cylinder dipole with a shorter spacing. For the dipole versus monopole task, the objects were either stationary or in motion during each trial. The dipole and monopole objects varied from trial to trial in the left-right position while also roving in range (10-40 cm), cross range separation (15-40 cm), and dipole aspect angle (0 degrees -90 degrees ).

Changes in signal parameters over time for an echolocating Atlantic bottlenose dolphin performing the same target discrimination task.

This study documents the changes in peak frequency, source level, and spectrum shape of echolocation clicks made by the same dolphin performing the same discrimination task in 1998 and in 2003/2004 with spherical solid stainless steel and brass targets. The total average peak frequency used in 1998 was 138 kHz but in 2003/2004 it had shifted down nearly 3.5 octaves to 40 kHz.

Human listeners provide insights into echo features used by dolphins (Tursiops truncatus) to discriminate among objects.

Echolocating bottlenose dolphins (Tursiops truncatus) discriminate between objects on the basis of the echoes reflected by the objects. However, it is not clear which echo features are important for object discrimination. To gain insight into the salient features, the authors had a dolphin perform a match-to-sample task and then presented human listeners with echoes from the same objects used in the dolphin's task.

Echo features used by human listeners to discriminate among objects that vary in material or wall thickness: implications for echolocating dolphins.

Echolocating dolphins extract object feature information from the acoustic parameters of echoes. To gain insight into which acoustic parameters are important for object discrimination, human listeners were presented with echoes from objects used in two discrimination tasks performed by dolphins: Hollow cylinders with varying wall thicknesses (+/-0.2, 0.

Acoustic features of objects matched by an echolocating bottlenose dolphin.

The focus of this study was to investigate how dolphins use acoustic features in returning echolocation signals to discriminate among objects. An echolocating dolphin performed a match-to-sample task with objects that varied in size, shape, material, and texture. After the task was completed, the features of the object echoes were measured (e.