Category: Uncategorized

How do apes and humans differ? There are a lot of answers, but one way is communication! Esther Hermann and Michael Tomasello conducted research to test an ape’s ability to understand a human’s communicative motive. To do this they took a look at how an ape interprets pointing. Additionally, the researchers did the same tests to children (18 and 24 months old) and compared the results of the apes to the children!

Hermann and Tomasello used two conditions in their study: informing and prohibiting. The informing condition determined whether the subjects understood a cooperative relationship, while the prohibiting condition determined whether the subject understood a competitive relationship.

Apes

Each subject first went through a warm-up to make sure they understood what to do. After the warm-up, two experimenters established a relationship with the ape. One was a cooperative relationship for the informing condition, while the other was a competitive relationship for the prohibiting condition, then the trials began.

In the informing condition the experimenter,

• pointed to the container with food
• said in a positive tone, ‘Look here‘
• alternated looking at the cup and the ape

In the prohibiting condition the experimenter,

• gestured toward the container with food and in a negative tone said, ‘No, don’t take this one!‘
• avoided eye contact with the ape by staring at the container
• would bang on the glass and pretend to be angry if the ape retrieved the food!

The graph below shows the apes’ combined group scores. Looking at the graph, we see that the apes significantly found more food in the prohibiting condition than in the informing condition. The study concluded that these results suggest apes do not understand a cooperative or friendly cue in the context studied.

Children

The children also went through a warm-up, where the experimenters played with the children so they could be familiar with one another, as well as learn what to do before the trials started. During the trials, experimenter 1 hid the toy, gave an informing or prohibiting cue, and left the room. The child was then able to choose a box by approaching and opening it.

In the informing condition the experimenter,

• would hide the toy,
• with a positive tone say, ‘Look here‘,
• then would alternate looking at the child and the box with the toy

In the prohibiting condition the experimenter,

• would talk to herself about a toy she was holding, then place it under a box
• would then give a gesture and in a negative tone say, ‘No, don’t take this one!‘
• looked at the box to avoid eye contact with the child

The graph below shows the average percent correct (choosing the box with the hidden toy) for the informing and prohibiting conditions of the children. Looking at the graph, we can see that the 24-month-old children significantly found the toy more in the informing condition than the prohibiting condition, while the 18-month-old children significantly found the toy more in the prohibiting condition!

The study concluded that these results suggest younger children more closely resemble the apes (better comprehension for the prohibiting or competitive condition), while older children are able to comprehend the informing or helpful cue.

What does this research mean?

This research supports the idea that apes possess more skills in competitive than cooperative contexts. It also supports the idea that humans are able to interact and understand each other in ways apes cannot. That being said, we must remember not every study can account for every single factor that may influence a decision. Therefore, there are limitations in this study.

For example, when conducting the trials, the child is held in their mother’s arms while the ape is secluded. This creates 2 different environments, where the child may get to feel more comfortable with its mother, while the ape is aware of its solitude. Additionally, this study combined results of 2 different ape species (chimpanzees and bonobos), both of which have different characteristics, personalities, and cognitive abilities.

This study provides great information on how apes and children may think and make decisions. But there is still more research to be done and science continues to ask, “What can these creatures do?”

To read the study in full follow the link below.

Apes’ and children’s understanding of cooperative and competitive motives in a communicative situation

Author: Courtney Lewis

Editor: Joclyn Villegas

A Review of “Cultural Confusion: Parsimony, Social Learning, and Humpback Whales” By Heidi Lyn

Humpback whales are well known for their elaborate vocal songs, but how do they learn these? Dr. Heidi Lyn – a comparative psychologist studying cognition and communication in non-human animals – has taken a look at how scientists have analyzed this type of communication. She has recently discussed a notable issue with Dr. Mercado’s (2022) parsimonious view on humpback whale song analyses.

Parsimony is the idea that the simplest explanation is often the best, and Mecado’s heavy reliance on two components of parsimony:

• Parsimony of explanation
• Parsimony of mechanism

But, these ideas don’t quite fit the ideas of how language can evolve and shift over time. Parsimony of explanation is when the simplest explanation is often the one preferred. Parsimony of mechanism is when the simplest of mechanism is preferred. Occam’s razor is a great place to start, when trying to understand the premise of parsimony and how it is applied to research. 

In contrast to Mecado’s idea surrounding whale song, Lyn provides evidence that social learning and culture may be factors that influence the formation and spread of whale songs. 

Social learning provides an evolutionary upper hand when animals such as the humpback whale can learn from conspecifics rather than having to learn from ground zero (evidence against Mercado’s idea). An example of social learning is imitation, where animals copy behaviors or sounds of another.

Dr. Lyn notes that culture is more difficult to be said as a certain factor, since the definition of culture is debated itself. A popular definition by Whitten et al. (1999) states “A cultural behavior “is one that is transmitted repeatedly through social or observational learning to become a population-level characteristic”. However, not all scientists use this definition. While research continues to clarify “What is culture?“, Dr. Lyn argues that we cannot eliminate this as something humpback whales experience.

Additionally, parsimony of mechanism may not always be the answer. The idea that one mechanism is better than two, does not cover what is expressed by vocal systems that commonly use more than one mechanism of change. These changes in vocal systems are consistent across language and stand in contrast to explanations based on parsimony. In other words, the simplest explanation is arbitrary when understanding vocal communication — it is complex.

Dr. Lyn shows that while parsimony can back explanation on many things, humpback whale song is complex and should remain so. In her publication, Lyn has provided strong evidence that explanations based on parsimony alone are often based on “rhetoric and strong man arguments” and should be taken with a grain of salt.

so what does this mean?

Whale songs are an incredible form of communication! Sometimes, simplifying a system that has many knobs and whistles, maybe simplifying it too much. When we reduce a process down to the bare bones, we can miss out on some really interesting information. If we want to learn more about how intelligent and complex these marine mammals are, then we must allow the idea that they are capable of building a complex system.

To read more, link below.

Click to access 4-lyn_abc_92.pdf

Reviewed by: Katie West with insight from Dr. Lindsey Johnson

With human activity increasing both in coastal and deep ocean, the world’s ocean has become quite a noisy environment. Concerned researchers have investigated how this may be impacting marine life, including marine mammals.

One study has investigated the potential effects of pile driving on the dynamics of bottlenose dolphin populations.

Importance of Sound to Bottlenose Dolphins

Bottlenose dolphins use sound to:

• investigate and understand their environment
• find and capture prey
• transmit information to other members or conspecifics

Depending on the surrounding contexts, dolphins will utilize different sound types and project the soundwave at varying frequencies and sound levels (Table 1). Approximately, unmodulated whistles within 3.5-10 kHz have an effective range of 14-25 km. However, when the whistle frequency increases to 12 kHz, the effective range decrease to 1.5-4 km. Pulsed sounds, such as clicks, rarely travel further than a few kilometers.

Table 1.

Sound Type	Frequency Range (kHz)	Dominant Frequencies (kHz)	Source Level (dB re μPa at 1m)
Whistles	0.80-30	3.5-14.5	125-173
Clicks	0.10-300	15.0-130	218-228

Sound Generated by Pile Driving

On average, an individual pile driving pulse generates a sound source level of 151 dB re 1 μPa. Dr. Mciwem (2006) summarized potential masking of dolphin call types (i.e., whistles, clicks) in the figure below.

The figure depicts how 3 different frequencies (9, 50, 115 kHz), commonly used by dolphins, dissipates as the sound travels further from the source. Sounds that lie under the lines of the pile driving hammers (i.e., diesel, drop) potentially mask dolphins sounds.

At 9kHz (top panel), the drop hammer could mask vocalizations at a radius of 1.3 km; while the diesel hammer potentially masks vocals over 40 km away.

At 50 kHz, the diesel hammer could mask echolocation clicks up to 6 km away, and the drop hammer up to 0.2 km.

At 115 kHz, the diesel hammer could mask echolocation clicks up to 1.2 km away, and the drop hammer 0 km.

What does this mean?

Here, we see that depending on the loudness of a sound received by and call type – dolphin vocalizations have the potential to be masked or go unheard by a conspecific. Masking may cause dolphins to change the frequency range, loudness or even how often they emit signals. This can cause additional excursion of energy, or possibly change vocal composition of specific social groups. Masking could also influence missed opportunities to mate or receiving vital information from another individual because signals were not heard.

It is important to keep in mind that this information comes a single review study and only goes over potential sound interference from pile driving. However, there are multiple sounds, both natural and human-made, occurring all at once. Therefore, the influence of masking may be underestimated. Scientists continue to do work on understanding the full spectra of masking.

We are working hard to get the new website up and running and full of links where you can find our work and our information. Hope there will be more soon!

Due to the Ongoing COVID-19 restrictions, we currently have no research ongoing in the lab rooms. We continue to analyze and write up our data and we plan big things for the year ahead – stay tuned!